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Purpose Mitigation strategies to balance the risk of coronavirus disease 2019 (COVID-19) infection against oncologic risk in patients with breast cancer undergoing radiation therapy have been deployed. To this end, shorter hypofractionated regimens have been recommended where appropriate, with prioritization of radiation therapy by oncologic risk and omission or deferral of radiation therapy for lower risk cases. Timely adoption of these measures reduces COVID-19 risk to both patients and health care workers and preserves resources. Herein, we present our early response and adaptation of breast radiation therapy utilization during the COVID-19 pandemic at a large academic cancer center in Canada. Methods and Materials A state of emergency was announced in Ontario on March 17, 2020, owing to the COVID-19 pandemic. Emergency guidelines were instituted. To examine our response, the number of weekly breast radiation therapy starts, type of breast radiation therapy, and patient age were compared from March 1 to April 30, 2020 to the same period in 2019. Results After the declaration of emergency in Ontario, there was a decrease of 39% in radiation therapy starts in 2020 compared with 2019 (79 vs 129, P < .001). There was a relative increase in the proportion of patients receiving regional nodal irradiation (RNI) in 2020 compared with 2019 (46% vs 29%, respectively), with the introduction of hypofractionated RNI in 2020 (27 of 54 cases, 50%). A smaller proportion of patients starting radiation therapy were aged >50 years in 2020, 66% (78 of 118) versus 83% (132 of 160) in 2019, P = .0027. Conclusions A significant reduction in breast radiation therapy starts was noted during the early response to the COVID-19 pandemic, with prioritization of radiation therapy to patients associated with higher oncologic risk requiring RNI. A quick response to a health care crisis is critical and is of particular importance for higher volume cancer sites where the potential effect on resources is greater.

Highlights • Treatment of cervical cancer with definitive chemo-radiation can be associated with distress. • Cervical cancer patients distress at diagnosis is predictive of distress in follow-up. • These symptoms significantly improve over time to an extent that is meaningful for patients. • This information can be used to inform survivorship planning., Background and purpose To evaluate longitudinal patient-reported distress in cervical cancer patients treated with definitive chemoradiation (CRT). Materials and methods Between 2011 and 2016, consenting cervical cancer patients treated with definitive CRT who completed ≥ 2 revised Edmonton Symptom Assessment System (ESAS-r) questionnaires at clinical visits, including baseline, were included. A linear mixed model was used to assess the longitudinal trend in ESAS-r. A minimal clinically important difference (MCID) for total ESAS-r score was defined as a change of 3-points for improvement and 4-points for deterioration. The proportion of patients with an MCID over time was described using moving averages. To test for changes, mixed effects logistic models were fitted, each of which included patient-specific random intercepts and random slopes. Results 67 patients were eligible for analysis (736 ESAS-r assessments). Median (range) follow-up was 24 months (range: 15–45) and compliance at 12 months was 60% (40/67). There was a significant decrease in ESAS-r scores over time. Baseline ESAS-r was strongly predictive of ESAS-r at follow-up (p

Purpose: Partial Breast Irradiation (PBI) treats the tumor bed plus a margin in low risk early stage breast cancers, reducing exposure to organs at risk. Randomized trials have shown that PBI with external beam radiotherapy is non-inferior to whole breast irradiation in terms of local control with fewer late normal tissue adverse events. We aimed to determine the proportion of women with early stage breast cancer suitable for external beam PBI at our institution using adapted ASTRO guidelines for accelerated PBI whereby both clinical-pathological factors and visualization of the tumor bed/cavity on planning scans were determined to quantify PBI eligibility. Methods: Patients were identified retrospectively from January 1, 2013 to November 1, 2018 based on age (≥55), tumor size (≤2cm invasive, ≤2.5cm DCIS), nodal negativity and grade (1 or 2). Cases identified were unifocal, lymphovascular invasion negative, ER positive, HER2 negative, with margins ≥2mm (invasive) and ≥3mm (DCIS), no chemotherapy, non-lobular, no extensive intraductal component, no previous/ bilateral cancers and endocrine therapy optional. Planning scans were reviewed to assess for presence of surgical clips and assigned cavity visualization scores (CVS); CVS 1=cavity not visualized, CVS 2=cavity visualized with indistinct margins, CVS 3=cavity visualised with some distinct margins and heterogeneous appearance, CVS 4= cavity visualised with mostly distinct margins and mildly heterogeneous appearance, CVS 5= all cavity margins clearly defined and homogeneous appearance. These features were used to determine if cases were considered radiologically suitable for PBI. Results: Thirty-seven percent (1051/2824) of cases identified were deemed eligible based on age, grade and T1N0/Tis. Of the 1051, 306 (29%) met all the pathologic criteria; the main reasons for exclusion were previous breast cancer, lobular histology, or multifocality. Median age of eligible cases was 65 years (range 55-88 years). The majority (254) had invasive disease (T1mi: 6, T1a: 17, T1b: 98, T1c: 133); 52 had DCIS. There were 169 right-sided and 137 left-sided cases. Endocrine therapy was documented in 55% of cases. CVS (1-5) were: 11%, 22%, 30%, 29%, 8%. Overall, 66% (201/306) of cases were considered radiologically suitable for PBI (of the 201 cases, 97% had CVS ≥3). Seventy-two cases (72/306; 24%) had tumor bed clips, of which, 34 were considered suitable for PBI (91% CVS ≥3; 9% CVS 2). Conclusions: Overall, a low proportion of all patients were eligible for PBI based on clinical features, but two-thirds of eligible cases were suitable for PBI based on CVS score alone. In contrast, the suitability for PBI within the cohort with surgical clip placement was low. Visualization of the tumor bed is essential to safely deliver PBI and is guided by identification of the cavity seroma and/or surgical clips. Development of standard practice guidelines for surgical clip positioning to identify the tumor bed will potentially assist in increasing the proportion of early stage breast cancer patients suitable to receive PBI, even if the CVS is less favorable. Citation Format: Christine Anne Koch, Gemma Corey, Kathy Han, Grace Lee, Tom Purdie, Chris McIntosh, Patricia Lindsay, Fei-Fei Liu, Anthony Fyles, Wilf Levin, Jennifer Croke, Aisling Barry, Danielle Rodin, Nhu Tram Nguyen, Tatiana Conrad. Evaluation of partial breast irradiation suitability in early stage breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-12-24.

Purpose: The aims of this study are to evaluate the stability of radiomic features from Apparent Diffusion Coefficient (ADC) maps of cervical cancer with respect to: (1) reproducibility in inter-observer delineation, and (2) image pre-processing (normalization/quantization) prior to feature extraction.Materials and methods: Two observers manually delineated the tumor on ADC maps derived from pretreatment diffusion-weighted Magnetic Resonance imaging of 81 patients with FIGO stage IB-IVA cervical cancer. First-order, shape, and texture features were extracted from the original and filtered images considering 5 different normalizations (four taken from the available literature, and one based on urine ADC) and two different quantization techniques (fixed-bin widths from 0.05 to 25, and fixed-bin count). Stability of radiomic features was assessed using intraclass correlation coefficient (ICC): poor (ICC Results: The approach using urine-normalized values together with a smaller bin width (0.05) was the most reproducible (428/552, 78% features with ICC >= 0.75); the fixed-bin count approach was the least (215/552, 39% with ICC >= 0.75). Without normalization, using a fixed bin width of 25, 348/552 (63%) of features had an ICC >= 0.75. Overall, 26% (range 25-30%) of the features were volume-dependent (rho >= 0.6). None of the volume-independent shape features were found to be reproducible.Conclusion: Applying normalization prior to features extraction increases the reproducibility of ADC-based radiomics features. When normalization is applied, a fixed-bin width approach with smaller widths is suggested. (C) 2019 The Author(s). Published by Elsevier B.V.

Summary Background Whole breast irradiation delivered once per day over 3–5 weeks after breast conserving surgery reduces local recurrence with good cosmetic results. Accelerated partial breast irradiation (APBI) delivered over 1 week to the tumour bed was developed to provide a more convenient treatment. In this trial, we investigated if external beam APBI was non-inferior to whole breast irradiation. Methods We did this multicentre, randomised, non-inferiority trial in 33 cancer centres in Canada, Australia and New Zealand. Women aged 40 years or older with ductal carcinoma in situ or node-negative breast cancer treated by breast conserving surgery were randomly assigned (1:1) to receive either external beam APBI (38·5 Gy in ten fractions delivered twice per day over 5–8 days) or whole breast irradiation (42·5 Gy in 16 fractions once per day over 21 days, or 50 Gy in 25 fractions once per day over 35 days). Patients and clinicans were not masked to treatment assignment. The primary outcome was ipsilateral breast tumour recurrence (IBTR), analysed by intention to treat. The trial was designed on the basis of an expected 5 year IBTR rate of 1·5% in the whole breast irradiation group with 85% power to exclude a 1·5% increase in the APBI group; non-inferiority was shown if the upper limit of the two-sided 90% CI for the IBTR hazard ratio (HR) was less than 2·02. This trial is registered with ClinicalTrials.gov , NCT00282035 . Findings Between Feb 7, 2006, and July 15, 2011, we enrolled 2135 women. 1070 were randomly assigned to receive APBI and 1065 were assigned to receive whole breast irradiation. Six patients in the APBI group withdrew before treatment, four more did not receive radiotherapy, and 16 patients received whole breast irradiation. In the whole breast irradiation group, 16 patients withdrew, and two more did not receive radiotherapy. In the APBI group, a further 14 patients were lost to follow-up and nine patients withdrew during the follow-up period. In the whole breast irradiation group, 20 patients were lost to follow-up and 35 withdrew during follow-up. Median follow-up was 8·6 years (IQR 7·3–9·9). The 8-year cumulative rates of IBTR were 3·0% (95% CI 1·9–4·0) in the APBI group and 2·8% (1·8–3·9) in the whole breast irradiation group. The HR for APBI versus whole breast radiation was 1·27 (90% CI 0·84–1·91). Acute radiation toxicity (grade ≥2, within 3 months of radiotherapy start) occurred less frequently in patients treated with APBI (300 [28%] of 1070 patients) than whole breast irradiation (484 [45%] of 1065 patients, p Interpretation External beam APBI was non-inferior to whole breast irradiation in preventing IBTR. Although less acute toxicity was observed, the regimen used was associated with an increase in moderate late toxicity and adverse cosmesis, which might be related to the twice per day treatment. Other approaches, such as treatment once per day, might not adversely affect cosmesis and should be studied. Funding Canadian Institutes for Health Research and Canadian Breast Cancer Research Alliance.

Highlights • A single biopsy may not accurately reflect the global hypoxia status of a tumor due to intratumoral heterogeneity. • Compared with individual genes, hypoxia gene expression signatures are generally more consistent across multiple biopsies from different regions of a tumor and may give a more reliable estimate of global hypoxia status. • Wherever possible, the use of multiple biopsies provides greater assurance in correctly classifying a tumor as more or less hypoxic., Background and Purpose Gene expression signatures are often used to identify hypoxic tumors. However, intratumoral heterogeneity raises concern that multiple biopsies may be necessary to assess global hypoxia status. The objective of this study was to compare the impact of heterogeneity on the discriminative capacity of several previously described hypoxia gene signatures and determine if a single biopsy is sufficient to obtain a reliable estimate of hypoxia in cervical cancer. Materials and Methods Multiple biopsies (33) were obtained from 11 locally advanced (FIGO IB to IVB) cervical cancers prior to treatment. Ten hypoxia gene signatures were analyzed. Variance component analysis was used to determine the ratio of within-tumor variability to total-tumor variability when one to five biopsies are available for analysis (W/T1–5). The mean standardized error in the signature scores was estimated by comparing the score using one biopsy randomly selected from each tumor to the ‘global’ score using all available biopsies. Results The ten hypoxia signatures were comprised of 6–99 genes each. The W/T1 ratios for individual genes commonly found in the signatures ranged from 0.17 to 0.73. W/T1 ratios for the signatures were generally lower (0.21–0.45), implying greater capacity to discriminate among tumors. With additional biopsies, the signature W/T ratios (ie W/T2-5) decreased further. The mean error in the signature scores varied from 0.27 to 0.40 of one standard deviation, suggesting high capacity to discriminate among tumors with different global hypoxia scores. Conclusions Compared with individual probes, hypoxia gene expression signatures are generally more consistent across multiple biopsies from different regions of a tumor and more tolerant of intratumoral heterogeneity.

Purpose Interstitial brachytherapy (ISBT) can be effective for vaginal tumors due to its ability to deliver conformal treatment with 3D planning. As there is no consensus for 3D vaginal brachytherapy (BT) contouring, the goals of this study are to evaluate the variability in practices and contouring, and to develop consensus concepts on target definitions. Methods A survey/contouring study was conducted with 16 radiation oncologists from 10 Canadian academic centers. The study included three vaginal ISBT cases. Participants were provided staging, prebrachytherapy (pre-BT), and BT MRIs. Participants responded to a questionnaire and contoured on the provided images. Agreement between contours was analyzed. A meeting was held to develop consensus definitions of targets. Results Median ISBT experience was 3.5 years. All 16 participants regularly contour with MRI, whereas three also plan on MRI. For the three cases, there was variation into how CTV HR and CTV IR was defined. Kappa statistics showed higher agreement with bulky tumors (mean 0.59) as compared with small residual tumors (mean 0.29). For all cases, kappa was highest in pre-BT GTV res as compared with BT GTV res (mean 0.58, 0.46). Consensus concepts to define targets were developed. Conclusions Variations exist in how ISBT targets are defined for vaginal tumors. Highest contouring variability was seen with small residual at BT. Contouring is more consistent on pre-BT MRI as compared with BT MRI suggesting a needle distortion effect. Consensus CTV HR and CTV IR definitions have been developed and further work is warranted to establish international standards.

Background The CXCL12/CXCR4 chemokine pathway is involved in cervical cancer pathogenesis and radiation treatment (RT) response. We previously reported that radiochemotherapy (RTCT) and concurrent administration of the CXCR4 inhibitor plerixafor improved primary tumour response. The aims of this study were to determine optimal sequencing of RTCT and plerixafor, the mechanisms responsible for improved response and the effect of plerixafor on late intestinal toxicity. Methods Orthotopic cervical cancer xenografts were treated with RTCT (30 Gy in 2 Gy fractions and cisplatin) with or without concurrent, adjuvant or continuous plerixafor. The endpoints were growth delay and molecular and immune cell changes at the end of treatment. Late intestinal toxicity was assessed by histologic examination of the rectum 90 days after a single 20 Gy fraction. Results RTCT increased CXCL12/CXCR4 signalling and the intratumoral accumulation of myeloid cells; the addition of plerixafor mitigated these effects. All of the RTCT and plerixafor arms showed prolonged tumour growth delay compared to RTCT alone, with the adjuvant arm showing the greatest improvement. Plerixafor also reduced late intestinal toxicity. Conclusion Adding Plerixafor to RTCT blunts treatment-induced increases in CXCL12/CXCR4 signalling, improves primary tumour response and reduces intestinal side effects. This combination warrants testing in future clinical trials.

Purpose: The aims of this study are to evaluate the stability of radiomic features from T2-weighted MRI of cervical cancer in three ways: (1) repeatability via test-retest; (2) reproducibility between diagnostic MRI and simulation MRI; (3) reproducibility in inter-observer setting.Materials and methods: This retrospective cohort study included FIGO stage IB-IVA cervical cancer patients treated with chemoradiation between 2005 and 2014. There were three cohorts of women corresponding to each aim of the study: (1) 8 women who underwent test-retest MRI; (2) 20 women who underwent MRI on different scanners (diagnostic and simulation MRI); (3) 34 women whose diagnostic MRIs were contoured by three observers. Radiomic features based on first-order statistics, shape features and texture features were extracted from the original, Laplacian of Gaussian (LoG)-filtered and wavelet-filtered images, for a total of 1761 features. Stability of radiomic features was assessed using intraclass correlation coefficient (ICC).Results: The inter-observer cohort had the most reproducible features (95.2% with ICC >= 0.75) whereas the diagnostic-simulation cohort had the fewest (14.1% with ICC >= 0.75). Overall, 229 features had ICC >= 0.75 in all three tests. Shape features emerged as the most stable features in all cohorts.Conclusion: The diagnostic-simulation test resulted in the fewest reproducible features. Further research in MRI-based radiomics is required to validate the use of reproducible features in prognostic models. (C) 2019 Elsevier B.V. All rights reserved.

Purpose The treatment of locally advanced cervical cancer with definitive chemoradiation (CRT) is associated with vaginal toxicity and altered sexual satisfaction. This prospective study assessed patient-reported sexual adjustment, vaginal dosimetry, and physician-reported vaginal toxicity in patients with cervical cancer treated with CRT and MR-guided brachytherapy (BT). Materials and Methods Between 2008 and 2010, International Federation of Gynecologists and Obstetricians stage IB-IVA patients with cervical cancer receiving definitive CRT were enrolled in a feasibility study assessing MR-guided BT. Patients completed the validated sexual adjustment questionnaire (SAQ) before BT (baseline) and during followup. Physician-reported vaginal toxicity was recorded. The International Commission on Radiation Units and Measurements rectovaginal point, mean vaginal dose, and D2cm3 were calculated. Mean SAQ scores at baseline and followup assessments were calculated. Mean time effects were estimated using a linear mixed-effects model. A multivariable linear mixed-effects model was used to examine the association between total and individual scores (repeated measures) and covariates. Results Sixty patients were approached to participate: 29 consented and 27 completed the SAQ at baseline and followup. The diagnosis of cervical cancer and treatment negatively impacted sexual relationships in 61% and 39%, respectively. There were no significant changes in sexual adjustment over time (p = 0.599). There were no associations between sexual adjustment and the International Commission on Radiation Units and Measurements rectovaginal point dose or clinical vaginal involvement. Patients with higher International Federation of Gynecologists and Obstetricians stages (≥IIB) had significantly worse sexual adjustment (p = 0.005). Conclusion CRT and MR-guided BT negatively impacted sexual relationships in patients with cervix cancer; however, there were no significant longitudinal changes in patient-reported sexual adjustment. Worse sexual adjustment may be associated with more advanced disease presentations.

Purpose: Our purpose was to investigate the interobserver variability in breast tumor bed delineation using magnetic resonance (MR) compared with computed tomography (CT) at baseline and to quantify the change in tumor bed volume between pretreatment and end-of-treatment MR for patients undergoing whole breast radiation therapy. Methods and Materials: Forty-eight patients with breast cancer planned for whole breast radiation therapy underwent CT and MR (T1, T1 fat-suppression [T1fs], and T2) simulation in the supine treatment position before radiation therapy and MR (T1, T1fs, and T2) at the end of treatment in the same position. Two observers delineated 50 tumor beds on the CT and all MR sequences and assigned cavity visualization scores to the images. The primary endpoint was interobserver variability, measured using the conformity index (CI). Results: The mean cavity visualization scores at baseline were 3.14 (CT), 3.26 (T1), 3.41 (T1fs), and 3.58 (T2). The mean CIs were 0.65, 0.65, 0.72, and 0.68, respectively. T1fs significantly improved interobserver variability compared with CT, T1, or T2 (P < .001, P < .001, and P = .011, respectively). The CI for T1fs was significantly higher than T1 and T2 at the end of treatment (mean 0.72, 0.64, and 0.66, respectively; P < .001). The mean tumor bed volume on the T1fs sequence decreased from 18 cm3 at baseline to 13 cm3 at the end of treatment (P < .01). Conclusions: T1fs reduced interobserver variability on both pre- and end-of-treatment scans and measured a reduction in tumor bed volume during whole breast radiation therapy. This rapid sequence could be easily used for adaptive boost or partial breast irradiation, especially on MR linear accelerators.

Purpose/Objective(s) Adjuvant radiation plays a significant role in reducing locoregional recurrences in uterine cancers. Standard treatment consists of daily radiation for 5 weeks which can be challenging for patients and the healthcare system, especially during the COVID pandemic. Hypofractionated radiotherapy has been evaluated and established in other pelvic malignancies. This study aims to evaluate the acute urinary and bowel toxicities, and patient reported outcomes following stereotactic hypofractionated adjuvant radiation for endometrial cancer. Materials/Methods This is a prospective phase I/II trial in which patients with endometrial cancer planned for adjuvant radiation received 30 Gy in 5 fractions, every other day or once weekly. Treatment was delivered at two centers with volumetric arc radiation therapy with a body-vacuum immobilization, bowel enema and 3D image-guidance. Toxicity assessment, outcomes and patient reported quality of life (QOL, EORTC core QLQ-C30 and endometrial EN24) were collected at baseline, fractions (F) 3 and 5, and at regular follow-up intervals. Higher scores represent better global QOL/health status or worse symptoms (scale 0 – 100). Changes in QOL over time were investigated with linear mixed-effects models. A P-value threshold of 0.05 was used for statistical significance. A change in QOL score of ≥ 10 points was considered clinically significant. Results The median age of the 41 enrolled patients is 66 (range: 51 – 88). Histologies included 29 endometrioid adenocarcinoma, 8 serous/clear cell, 1 carcinosarcoma, and 3 dedifferentiated. Thirty patients had stage 1 disease while 3 had stage 2 and 8 stage 3. Seven patients received sequential chemotherapy and 3 had additional vault brachytherapy. Median follow-up is 9 months, with worst toxicity (GI or GU) of grade 1 and 2 in 63% and 24% respectively. No patients have experienced a grade 3 or higher toxicity. Patient-reported diarrhea and gastrointestinal domain scores were statistically significantly worse than baseline at F5 (mean paired difference = 27.2; 8.7, P Conclusion Stereotactic hypofractionated radiation for uterine cancers is feasible and well-tolerated with short-term follow-up. Longer follow-up and future randomized studies are needed to further evaluate this treatment.

Purpose/Objective(s) Tumor hypoxia is associated with poor response to radiation (RT) and chemotherapy, and worse treatment outcome. We previously discovered a novel mechanism of metformin in a xenograft model: enhancing tumor RT response by inhibiting tumor cell oxygen consumption. Our population-based study showed that cumulative dose of metformin after cervical cancer diagnosis was independently associated with a decreased risk of cervical cancer-specific mortality in diabetic women. Based on the pre-clinical and retrospective data, we hypothesized that metformin would decrease tumor hypoxia and improve tumor response to RT in locally advanced cervical cancer. Materials/Methods A window-of-opportunity, phase II randomized trial was performed in women with stage IB-IVA cervical adenocarcinoma, squamous cell or adenosquamous carcinoma. Patients underwent screening positron emission tomography (PET) imaging with hypoxia tracer fluoroazomycin arabinoside (FAZA). Those with non-hypoxic tumor (no FAZA uptake) were excluded. Patients with FAZA uptake were randomized centrally in a 2:1 ratio (in favor of metformin) to receive either metformin in combination with standard chemoRT or standard chemoRT alone. Metformin was started at 850mg once daily x 3 days, followed by 850mg twice daily throughout the entire duration of external radiotherapy. A second FAZA-PET/CT scan was performed after 1 week of metformin or no intervention in control group, just before start of chemoRT. The hypoxic volume was defined as all voxels within a tumor with standardized uptake values (SUVs) greater than 3 standard deviations (SD) from the mean gluteus maximus muscle SUV value. The hypoxic fraction (HF) was defined as the ratio of the number of hypoxic voxels to the total number of tumor voxels. The primary endpoint was absolute mean change in HF between the two FAZA-PET scans, compared using the Wilcoxon sign rank test. Disease-free survival (DFS) was defined as the duration of time from randomization to the time of relapse or death and compared using the log-rank test. Target accrual was 48 patients; the study was closed early to accrual due to FAZA availability and the COVID-19 pandemic. Results Of the twenty patients who consented, 6 were excluded due to no FAZA uptake and 1 withdrew. The median age of the 13 enrolled patients was 52; 8 (62%) had squamous cell carcinoma and 8 had stage IIB disease. HF of the 10 patients in the metformin arm decreased by an average of 10.2% (from 44.4% to 34.2%) ± SD 16.9% after 1 week of metformin, compared to an average increase of 4.7% (from 29.1% to 33.8%) ± 11.5% for the 3 patients in the control arm (P = 0.027). With a median follow-up of 2.8 years, the 2-year DFS was 67% for the metformin arm vs 33% for control (P = 0.09). Conclusion Metformin decreases cervical tumor hypoxia with a trend towards improved DFS in this trial. A larger confirmatory trial is warranted.

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Background Fatigue and insomnia are common symptoms experienced by breast cancer patients undergoing adjuvant radiation therapy (RT), yet the underlying mechanisms of these symptoms are unclear. In particular, the roles of hematopoietic stem cells (HSCs) and inflammatory cytokines remain to be elucidated. Methods Breast cancer patients (n = 147) completed questionnaires to longitudinally assess symptoms before, during, and after adjuvant RT. Phlebotomies were performed prior to RT, at the second and fifth treatment fractions, end of treatment (EOT), and 1 month after completing RT, assessing for CD34+, CD45+, full hematology, and 17 inflammatory cytokines. The associations between symptoms and all biomarkers were evaluated. All statistical tests were 2-sided. Results General fatigue and insomnia worsened with RT, with peak levels observed at EOT, which remained statistically significant even after controlling for anxiety and depression (P Conclusions This is the first longitudinal study to examine linkages between symptoms, HSCs, and cytokines, demonstrating that fatigue and insomnia shared associations with increasing serum levels of IP-10 and TNF-RII, and mental fatigue was associated with increasing serum levels of MMP-2. Our findings highlight opportunities for further research into mechanisms and potential interventions for these symptoms.

Neoadjuvant chemotherapy (NAC) is standard of care for locally advanced breast cancer. There is wide variation in radiation therapy (RT) practice and limited data describing locoregional relapse (LRR) after NAC. We hypothesized a low LRR risk with modern NAC, surgery, and RT and aimed to elucidate patterns of LRR and predictors of disease-free survival (DFS) and overall survival (OS) in these patients.Data from 416 patients with stage II/III breast cancer treated between 2008 and 2015 with NAC, surgery, and adjuvant RT were reviewed retrospectively. DFS and OS rates were calculated using the Kaplan-Meier method. The LRR rate was estimated using the cumulative incidence function, treating death as a competing risk. Multivariable survival analysis was performed using Cox regression.Median follow-up was 4.7 years. Most patients had cT2/3 (74%) cN1 (61%) disease and underwent mastectomy (75%) and axillary dissection (84%). Pathologic complete response (pCR) was achieved in 22% of patients. There were 27 LRRs (including 4 isolated LRRs) and 89 distant failures. Two patients developed LRR 2 months after surgery, before adjuvant RT. LRR could be mapped in 23 patients: most (20) recurred within the RT field; 1 in- and out-of-field; and 2 out-of-field. Five-year LRR, DFS, and OS were 6.4%, 77%, and 90%, respectively. On multivariable analysis, triple-negative subtype (hazard ratio [HR] 2.82; 95% confidence interval [CI], 1.78-4.47; P.001), stage III disease (HR 1.72; 95% CI, 1.11-2.69; P = .016), and non-pCR (HR 4.76; 95% CI 2.13-10.0; P.001) were associated with poor DFS and OS (HR 4.13 [95% CI, 2.21-7.72; P.001]; HR 1.94 [95% CI, 1.001-3.75; P = .049]; and HR 2.38 [95% CI, 0.98-5.88; P = .055], respectively).Patients with breast cancer treated with modern NAC, surgery, and RT have a low 5-year LRR risk, with the majority occurring in-field. Triple-negative subtype, stage III disease, and non-pCR were associated with inferior DFS and OS.

Purpose To assess cervical tumor hypoxia using the hypoxia tracer 18F-fluoroazomycin arabinoside (18F-FAZA) and compare different reference tissues and thresholds for quantifying tumor hypoxia. Methods and Materials Twenty-seven patients with cervical cancer were studied prospectively by positron emission tomography (PET) imaging with 18F-FAZA before starting standard chemoradiation. The hypoxic volume was defined as all voxels within a tumor (T) with standardized uptake values (SUVs) greater than 3 standard deviations from the mean gluteus maximus muscle SUV value (M) or SUVs greater than 1 to 1.4 times the mean SUV value of the left ventricle, a blood (B) surrogate. The hypoxic fraction was defined as the ratio of the number of hypoxic voxels to the total number of tumor voxels. Results A 18F-FAZA-PET hypoxic volume could be identified in the majority of cervical tumors (89% when using T/M or T/B > 1.2 as threshold) on the 2-hour static scan. The hypoxic fraction ranged from 0% to 99% (median 31%) when defined using the T/M threshold and from 0% to 78% (median 32%) with the T/B > 1.2 threshold. Hypoxic volumes derived from the different thresholds were highly correlated (Spearman's correlation coefficient ρ between T/M and T/B > 1-1.4 were 0.82-0.91), as were hypoxic fractions (0.75-0.85). Compartmental analysis of the dynamic scans showed k3, the FAZA accumulation constant, to be strongly correlated with hypoxic fraction defined using the T/M (Spearman's ρ=0.72) and T/B > 1.2 thresholds (0.76). Conclusions Hypoxia was detected in the majority of cervical tumors on 18F-FAZA-PET imaging. The extent of hypoxia varied markedly between tumors but not significantly with different reference tissues/thresholds.

Purpose To determine whether plasma human papillomavirus (HPV) DNA predates clinical recurrence and compare its accuracy with 3-month fluorodeoxyglucose positron emission tomography (FDG-PET) in locally advanced cervical cancer. Methods This prospective multicenter study accrued 23 women with stage IB to IVA cervical cancer planned for definitive chemoradiation therapy (CRT). Plasma HPV DNA was measured serially by digital polymerase chain reaction, and FDG-PET was performed at 3 months post-CRT. Results Of the 19 women with HPV+ cervical cancer included in this analysis, 32% were stage IB, 58% IIB, and 10% IIIB/IVA. Median follow-up was 24 months (range, 18 to 30 months). All patients had detectable plasma HPV DNA before treatment. Six patients had detectable plasma HPV DNA at the end of CRT, and three of them developed metastases at 3 months. Of the 13 patients with undetectable plasma HPV DNA at end of CRT, to date, only one has developed recurrence. Six of those 13 patients had a positive 3-month FDG-PET with no definite residual disease on subsequent imaging or clinical examination to date, and four of these six had undetectable plasma HPV DNA at 3 months. Patients with undetectable plasma HPV DNA at end of CRT had significantly higher 18-month progression-free survival than those with detectable plasma HPV DNA (92% v 50%; P = .02). The area under the receiver operating characteristic curve (accuracy) of 3-month plasma HPV DNA and 3-month FDG-PET imaging for predicting recurrence at 18 months were 77% and 60%, respectively ( P = .008). Conclusion Detectable plasma HPV DNA at end of CRT predates the clinical diagnosis of metastases and is associated with inferior progression-free survival. Moreover, 3-month plasma HPV DNA level is more accurate than 3-month FDG-PET imaging in detecting residual disease. The clinical utility of plasma HPV DNA detection for guiding adjuvant/salvage therapy should be evaluated in future studies.

// Ali Hosni 1 , Kathy Han 1 , Lisa W. Le 2 , Jolie Ringash 1 , James Brierley 1 , Rebecca Wong 1 , Robert Dinniwell 1 , Anthony Brade 1 , Laura A. Dawson 1 , Bernard J. Cummings 1 , Monika K. Krzyzanowska 3 , Eric X. Chen 3 , David Hedley 3 , Jennifer Knox 3 , Alexandra M. Easson 4 , Patricia Lindsay 1 , Tim Craig 1 and John Kim 1 1 Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON, Canada 2 Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada 3 Department of Medical Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON, Canada 4 Department of Surgical Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON, Canada Correspondence to: John Kim, email: john.kim@rmp.uhn.ca Keywords: anal cancer; chemoradiotherapy; IMRT; pattern of failure; outcomes Received: November 11, 2017 Accepted: February 27, 2018 Published: April 17, 2018 ABSTRACT Purpose: Patterns of failure and long term outcomes were prospectively evaluated following tumor factors-stratified radiation dose for anal/perianal cancer. Methods: Between 2008–2013, patients with anal/perianal squamous cell carcinoma were accrued to an institutional REB-approved prospective study. All patients were treated with image-guided intensity-modulated radiation therapy (IG-IMRT). Radiation dose selection (27–36 Gy for elective target, and 45–63 Gy for gross target) was based on tumor clinico-pathologic features. Chemotherapy regimen was 5-fluorouracil/mitomycin-C (weeks 1&5). Local [LF], regional failure [RF], distant metastasis [DM], overall- [OS], disease-free [DFS], colostomy-free survival [CFS] and late toxicity were analyzed. Results: Overall, 101 patients were evaluated; median follow-up: 56.5 months; 49.5% male; 34.7% T3/4-category, and 35.6% N+. Median radiation dose was 63 Gy. The most common acute grade ≥3 toxicities were skin (41.6%) and hematological (30.7%). Five-year OS, DFS, CFS, LF, RF, DM rates were 83.4%, 75.7%, 74.7, 13.9%, 4.6% and 5% respectively. Five-year LF for patients with T1-2 and T3-4 disease were 0% and 39.2% respectively. All LF ( n = 14, after 63 Gy, in tumors ≥5 cm) were in the high dose volume except one marginal to the high dose volume. All RF ( n = 4) were within elective dose volume except one within the high dose volume. On multivariable analysis, T3/4-category predicted for poor DFS, CFS and OS. The overall late grade ≥3 toxicity was 36.2% (mainly anal [20%]). Conclusions: Individualized radiation dose selection using IG-IMRT resulted in good long term outcomes. However, central failures remain a problem for locally advanced tumors even with high dose radiation (63 Gy/7weeks).

Cervical cancer is the fourth most commonly diagnosed cancer and the fourth leading cause of cancer death in women worldwide. Approximately half of cervical cancer patients present with locally advanced disease, for which surgery is not an option. These cases are nonetheless potentially curable with radiotherapy and cisplatin chemotherapy. Unfortunately, some tumours are resistant to treatment, and lymph node and distant recurrences are major problems in patients with advanced disease at diagnosis. New targeted treatments that can overcome treatment resistance and reduce metastases are urgently needed. The CXCL12/CXCR4 chemokine pathway is ubiquitously expressed in many normal tissues and cancers, including cervical cancer. Emerging evidence indicates that it plays a central role in cervical cancer pathogenesis, malignant progression, the development of metastases and radiation treatment response. Pre-clinical studies of standard-of-care fractionated radiotherapy and concurrent weekly cisplatin plus the CXCR4 inhibitor Plerixafor (AMD3100) in patient-derived orthotopic cervical cancer xenografts have shown improved primary tumour response and reduced lymph node metastases with no increase in early or late side effects. These studies have pointed the way forward to future clinical trials of radiotherapy/cisplatin plus Plerixafor or other newly emerging CXCL12 or CXCR4 inhibitors in women with cervical cancer.

PURPOSE/OBJECTIVE(S) In response to the COVID-19 pandemic, radiotherapy (RT) departments around the world created new policies as a means of reducing risk of exposure for patients and staff, while attempting to maintain high-quality RT. We aim to describe the impact of the pandemic on changes in breast cancer RT patterns of practice for new patient referrals at a tertiary cancer center. MATERIALS/METHODS Newly diagnosed breast cancer patients referred to our department from March 17-June 30, 2020 were included. Referrals for palliative RT were excluded. Demographic characteristics, COVID-19 status (if available) and RT treatment information, including deviations from usual practice because of the pandemic, were extracted from medical records by independent reviewers, and validated by the treating radiation oncologist. Descriptive statistics were used to summarize the data. The results were compared to breast cancer patients treated from March 17-June 30, 2019. RESULTS A total of 271 and 306 patients met selection criteria for the 2020 and 2019 cohorts, respectively. The majority of consultations in 2020 were virtual (96%), conducted via telephone or videoconference, whereas in 2019 all were conducted in-person. Median age of the cohorts was similar: 58 years (range: 24-86) in 2020 and 59 years (range: 26-88) in 2019. Of those treated with adjuvant RT (n = 209), 56% of patients received whole breast (WB), 36% regional nodal irradiation (RNI) and 8% partial breast (PB) RT in 2020, whereas in 2019 (n = 284), 60% received WB, 31% RNI and 9% PB (Chi-squared test P = 0.43). As a result of the pandemic, 78% of cases (n = 211) received one or more deviations in RT practice compared to pre-pandemic institutional policies. The most common was an "altered dose/fractionation protocol" (n = 197; 93%), such as use of hypofractionated RNI (2020: 97%, 74/76 cases vs. 2019: 3%, 3/87 cases) or the FAST Forward regimen (2020: 43%, 57/134 WB/PB cases vs. 2019: 0/197 cases). Other deviations included a delay in RT start (defined as > 12 weeks post-op) noted in 11% (n = 29) and omission of RT in only 8% (n = 17), both were recommended when the risks associated with COVID-19 were felt to outweigh the benefit of RT. One patient had a deviation in RT as a result of testing positive for COVID-19. CONCLUSION In order to minimize hospital visits in response to the COVID-19 pandemic, a substantial proportion of breast cancer patients were seen virtually and treated with newer hypofractionated dose schedules, while total omission of adjuvant RT was infrequently observed. Continuously tracking patterns of practice provides an opportunity to evaluate the impact of the pandemic on clinical outcomes and help inform post-pandemic value-enhancing practices.

Background and purpose Hypoxia, high interstitial fluid pressure (IFP) and immune effects have individually been shown to modulate radiotherapy (RT) response in cervical cancer. The aim of this study was to investigate the interplay between hypoxia or IFP and circulating neutrophil levels, and their combined effect on survival following RT. Material and methods A total of 287 FIGO stage IB to IIIB cervical cancer patients treated with RT or RT and cisplatin (RTCT) were included. Tumor hypoxia and IFP were measured at baseline prior to treatment. Absolute neutrophil count (ANC) was measured at baseline and weekly during treatment. Median follow up was 7.1 years. Results High nadir ANC at the point of maximal myelosuppression was a stronger predictor of inferior survival than high baseline ANC after adjusting for clinical prognostic factors and treatment (RT vs. RTCT). The predictive effect of nadir ANC was most evident in patients with well-oxygenated tumors or tumors with high IFP at diagnosis. Conclusions This study provides new information about the combined influence of the tumor microenvironment and myeloid cells on the survival of cervical cancer patients treated with RT/RTCT to motivate the development of new treatments based on molecular targeting of immune–based radioresistance pathways.

Cervical cancer is the most common gynecologic malignancy worldwide.[1][1] The recommendation of adjuvant treatment following radical hysterectomy in early stage cervical cancer is usually tailored according to International Federation of Gynecology andObstetrics (FIGO) stage and risk factors.[1][1

Background: We developed and validated a prognostic gene expression signature which identifies women with cervical cancer with a higher risk for recurrence. Methods: Tumor biopsies were obtained from 81 women (PM cohort) with locally advanced cervical cancer prior to curative-intent chemoradiotherapy (RTCT; median follow-up 6·8 years). Whole genome RNA sequencing was performed. Using a five-fold cross validation, 69 genes were selected. Principal component (PC) analysis was applied and 4 PCs were associated with disease-free survival (DFS) using a Cox proportional hazards model. The risk score was calculated as the product of the coefficients from the Cox model, the PC rotation coefficients, and the gene expression levels. The risk score was externally validated using a cohort of 206 cervical cancer patients from TCGA who received curative intent treatment with RTCT or surgery +/- RTCT (median follow-up 2·2 years). Findings: The 69-gene risk score was strongly associated with DFS in the PM cohort (HR 2·72, 95%CI 2·06-3·59, p

Purpose Our purpose was to present and evaluate expert consensus on contouring primary breast tumors on magnetic resonance imaging (MRI) in the setting of neoadjuvant partial breast irradiation in trials. Methods and Materials Expert consensus on contouring guidelines for target definition of primary breast tumors on contrast-enhanced MRI in trials was developed by an international team of experienced breast radiation oncologists and a dedicated breast radiologist during 3 meetings. At the first meeting, draft guidelines were developed through discussing and contouring 2 cases. At the second meeting 6 breast radiation oncologists delineated gross tumor volume (GTV) in 10 patients with early-stage breast cancer (cT1N0) according to draft guidelines. GTV was expanded isotropically (20 mm) to generate clinical target volume (CTV), excluding skin and chest wall. Delineations were reviewed for disagreement and guidelines were clarified accordingly. At the third meeting 5 radiation oncologists redelineated 6 cases using consensus-based guidelines. Interobserver variation of GTV and CTV was assessed using generalized conformity index (CI). CI was calculated as the sum of volumes each pair of observers agreed upon, divided by the sum of encompassing volumes for each pair of observers. Results For the 2 delineation sessions combined, mean GTV ranged between 0.19 and 2.44 cm3, CI for GTV ranged between 0.28 and 0.77, and CI for CTV between 0.77 and 0.94. The largest interobserver variation in GTV delineations was observed in cases with extended tumor spiculae, blood vessels near or markers within the tumor, or with increased enhancement of glandular breast tissue. Consensus-based guidelines stated to delineate all visible tumors on contrast enhanced–MRI scan 1 to 2 minutes after contrast injection and if a marker was inserted in the tumor to include this. Conclusions Expert-based consensus on contouring primary breast tumors on MRI in trials has been reached. This resulted in low interobserver variation for CTV in the context of a uniform 20 mm GTV to CTV expansion margin.

Introduction/Background There is limited data regarding the optimal management of premenopausal women with cervical lesions measuring ≥2 to Methodology Study hypothesis: Neoadjuvant chemotherapy (NACT) will be effective in reducing the size of the tumor and will enable fertility-sparing surgery (FSS) without compromising oncologic outcome. Primary objective: To evaluate the feasibility of preserving fertility. Secondary objectives: To evaluate response rate to NACT, surgical complications and rate of FSS, overall survival up to 3 years for patients who completed NACT and FSS. Trial design: Premenopausal women diagnosed with stage IB2, ≥2 to Major eligibility criteria: Patients must have histologically confirmed invasive cervical cancer, ≥2 to Results Primary endpoints: Assess the rate of functional uterus defined as successful FSS and no adjuvant therapy. Exploratory objectives: Evaluate patients reported outcome and quality of life, ovarian function and rate of pregnancy during follow-up period (3 years). Translational research part is included. Conclusion This is a Phase II, prospective international trial. 90 evaluable patients will be needed to complete the study. A stopping rule will be activated if the recurrence rate at 2 years exceeds 10%. Activation is planned for the summer 2019. Disclosure Nothing to disclose.

OBJECTIVE The objective of this study was to determine the outcomes of patients with unresectable endometrial cancer managed with definitive or neoadjuvant radiation (RT) and/or chemotherapy. MATERIALS AND METHODS Patients with unresectable stages II to IVA endometrial cancer who were treated with curative intent between January 2000 and March 2018 were identified. Overall survival (OS) and disease-free survival (DFS) were analyzed using the Kaplan-Meier method and compared using the log-rank test. Multivariate logistic regression analysis was performed to identify factors associated with receipt of surgery. Multivariate Cox regression analysis was performed to identify factors associated with OS and DFS. RESULTS Of the 59 patients identified, the median age was 63 years (range: 37 to 88 y) and histology was endometrioid in 59%. Median follow-up was 2.2 years (range: 0.3 to 9.8 y). Seventeen patients (29%) received neoadjuvant chemotherapy, 28 (47%) neoadjuvant radiation, and 14 (24%) definitive RT; 39 (66%) underwent surgery. Patients who received surgery had higher 3-year OS and DFS than those who did not (84% vs. 41%; P

BackgroundThere are limited data regarding the optimal management of pre-menopausal women with cervical lesions measuring 2–4 cm who desire to preserve fertility.Primary objectivesTo evaluate the feasibility of preserving fertility.Study hypothesisNeo-adjuvant chemotherapy will be effective in reducing the size of the tumor and will enable fertility-sparing surgery without compromising oncologic outcome.Trial designPre-menopausal women diagnosed with stage International Federation of Gynecology and Obstetrics (FIGO) IB2, 2–4 cm cervical cancer who wish to preserve fertility will receive three cycles of platinum/paclitaxel chemotherapy. Patients with complete/partial response will undergo fertility-sparing surgery. Patients will be followed for 3 years to monitor outcome. Patients with suboptimal response (residual lesion ≥2 cm) will receive definitive radical hysterectomy and/or chemoradiation.Major eligibility criteriaPatients must have histologically confirmed invasive cervical cancer, 2–4 cm lesion, by clinical examination and magnetic resonance imaging (MRI), negative node, and pre-menopausal (≤40 years old). Following three cycles of neo-adjuvant chemotherapy, patients must achieve a complete/partial response (residual lesion Primary endpointsAssess the rate of functional uterus defined as successful fertility-sparing surgery and no adjuvant therapy.Sample sizeA total of 90 evaluable patients will be needed to complete the study.Estimated dates for completing accrual and presenting resultsExpected complete accrual in 2022 with presentation of results by 2025.Trial registration numberPending ethics submission.

Purpose Recurrences of previously irradiated gynecological malignancies are uncommon. Standardized management of these cases is not well established. We aim to provide an in-depth literature review and present current practice patterns among an international group of experienced practitioners in the reirradiation setting of gynecologic cancers. Methods and Materials An extensive literature search was performed and 35 articles were selected based on preset criteria. A 20-question online survey of 10 experts regarding their retreatment practices was also conducted. Results The reviewed publications include a diverse group of patients, multiple treatment techniques, a range of total doses, local control, overall survival, and toxicity outcomes. Overall, local control ranged from 44% to 88% over 1–5 years with OS in the range of 39.5–82% at 2–5 years. Late G3–4 toxicity varied very broadly from 0% to 42.9%, with most papers reporting serious toxicities greater than 15%. The most common reirradiation technique utilized was brachytherapy. Some low-dose-rate data suggest improved outcomes with doses >50 Gy. The high-dose-rate data are more varied with some studies suggesting improved local control with doses >40 Gy. In general, a longer time interval between the first and second course of radiation as well as recurrences Conclusions Reirradiation with brachytherapy results in relatively reasonable local control and toxicities for women with recurrent gynecologic cancers. The appropriate dose for each case needs to be individualized given the heterogeneity of cases. Multidisciplinary management is critical to develop individualized plans and to clearly communicate potential side effects and expected treatment outcomes. Take Home Message Reirradiation with brachytherapy is an acceptable effective organ preserving approach for recurrent gynecologic cancers with a reasonable local control and toxicity profile. Each case requires multidisciplinary management to develop an individualized approach. Monitoring for potential long-term toxicities is essential.

Purpose Our purpose was to evaluate the usage and perceived benefit of surgical clips for breast radiation therapy planning in Canada, focusing on partial breast irradiation (PBI) after breast-conserving surgery. Methods and Materials A retrospective institutional review identified patients eligible for PBI based on clinicopathologic criteria, and tumor bed visualization was determined from computed tomography-planning scans. An online survey was subsequently distributed to Canadian radiation oncologists addressing the usage and added value of surgical clips for breast radiation therapy planning purposes. The survey also evaluated PBI usage and regimens. Responses were collected over a 4-week period. PBI regimen usage at our institution was also reviewed from May 1 to December 18, 2020. Results Based on clinicopathologic criteria, 306 patients were identified between 2013 and 2018 who were eligible for PBI. However, only 24% (72/306) of cases were noted to have surgical clips, of which over 50% did not assist in tumor bed localization due to inconsistent clip positioning. Similarly, nearly two-thirds (28/43) of survey respondents indicated that surgical clips are placed in the tumor bed in less than 50% of cases. Almost all respondents (42/43) indicated that surgical clips facilitate breast radiation therapy planning and favor the development of guidelines to increase the consistent placement of surgical clips in the tumor bed after breast-conserving surgery. Approximately two-thirds of respondents (28/43) offer PBI to eligible patients as routine treatment, with moderate hypofractionated regimens most commonly recommended. However, the 1-week daily regimen of 26 Gy in 5 fractions is now offered to the majority (77%) of patients at our institution. Conclusions There was strong agreement among Canadian radiation oncologists that surgical clip placement facilitates breast radiation therapy planning, and most favor the development of surgical guidelines for the consistent placement of surgical clips in this setting. With the growing use of PBI, accurate localization of the tumor bed is extremely important.

Background: Human papillomavirus (HPV)-associated cancers often present with locoregionally confined disease and are treated with curative intent. An emerging treatment paradigm includes radical therapy (i.e., chemoradiotherapy or surgery) followed by adjuvant treatment. Accurate detection of minimal residual disease (MRD) following radical therapy could enable personalized use of adjuvant treatment. The HPV genome offers a convenient circulating tumor (ct)DNA marker for HPV-associated cancers, but current methods such as digital (d)PCR provide insufficient accuracy for accurate MRD detection and for other clinical applications in patients with low disease burden. We asked whether a next-generation sequencing approach (HPV-seq) could provide quantitative and qualitative assessment of HPV ctDNA in low-disease-burden settings. Methods: We conducted preclinical technical validation studies on HPV-seq using cervix cancer cell lines. We then applied HPV-seq retrospectively to a prospective multicenter cohort study of locally advanced cervix cancer patients accrued from 2015 to 2016 (NCT02388698). Patients were treated with radical chemoradiotherapy with blood obtained at baseline, end of treatment, and 3 months post-treatment. Median follow-up was 27.5 months. In 38 plasma samples from 17 patients, HPV-seq results were compared with dPCR. The primary outcome was progression-free survival according to end-of-treatment HPV ctDNA detectability. Results: HPV-seq achieved reproducible detection of HPV DNA at levels Conclusions: HPV-seq is a quantitative method for ctDNA detection that outperforms dPCR. HPV-seq also reveals qualitative information about ctDNA fragments such as HPV genotype and ctDNA fragment length distribution. Our findings will have implications for MRD detection in HPV-related cancers. Future prospective studies are needed to confirm that patients with undetectable HPV ctDNA following chemoradiotherapy have exceptionally high cure rates. Citation Format: Eric Leung, Kathy Han, Jinfeng Zou, Zhen Zhao, Yangqiao Zheng, Ting Ting Wang, Lillian L. Siu, Trevor J. Pugh, Scott V. Bratman. HPV sequencing facilitates ultrasensitive detection of HPV circulating tumor DNA [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A45.

The standard treatment for endometrial cancer is upfront surgery. However, surgical resection is challenging in locally advanced cases extending to the vagina, bladder, bowel, rectum, or parametria. Historically, these cases were managed palliatively due to the inability to escalate radiation dose safely and accurately, and there is a paucity of literature supporting definitive radiation for these patients. Technological advances in brachytherapy, including magnetic resonance guidance (MR-guidance) and interstitial techniques, have improved target precision and dose escalation without additional toxicity to permit curative management. We report two cases of unresectable, locally advanced endometrial cancers treated with MR-guided radiation.

For volumes up to 2 cm3 of the bladder and possibly up to 5 cm3 of the rectum, doses computed from the whole organ were good estimates of the doses in the wall in cervix brachytherapy, and there were no significant differences between patients treated with or without interstitial needles.

PURPOSE: MR-guided brachytherapy (MRgBT) with interstitial needles is associated with improved outcomes in cervical cancer patients. However, there are implementation barriers, including magnetic resonance (MR) access, practitioner familiarity/comfort, and efficiency. This study explores a graded MRgBT implementation strategy that included the adaptive use of needles, strategic use of MR imaging/planning, and team learning.METHODS AND MATERIALS: Twenty patients with cervical cancer were treated with high-dose-rate MRgBT (28 Gy in four fractions, two insertions, daily MR imaging/planning). A tandem/ring applicator alone was used for the first insertion in most patients. Needles were added for the second insertion based on evaluation of the initial dosimetry. An interdisciplinary expert team reviewed and discussed the MR images and treatment plans.RESULTS: Dosimetry-trigger technique adaptation with the addition of needles for the second insertion improved target coverage in all patients with suboptimal dosimetry initially without compromising organ-at-risk (OAR) sparing. Target and OAR planning objectives were achieved in most patients. There were small or no systematic differences in tumor or OAR dosimetry between imaging/planning once per insertion vs. daily and only small random variations. Peer review and discussion of images, contours, and plans promoted learning and process development.CONCLUSIONS: Technique adaptation based on the initial dosimetry is an efficient approach to implementing MRgBT while gaining comfort with the use of needles. MR imaging and planning once per insertion is safe in most patients as long as applicator shifts, and large anatomical changes are excluded. Team learning is essential to building individual and programmatic competencies.