Search

The Anatomy and Radiology Contouring (ARC) Bootcamp was a face-to-face (F2F) intervention providing integrated education for radiation oncology (RO) residents and medical physicists. To increase access, we launched an online offering in 2019. We evaluated the effect of the online course on participants' knowledge acquisition, contouring skills, and self-confidence by comparing it with the F2F course.Using modules, the online course offers content similar to that of the F2F comparator. Participants from the 2019 F2F and the 2019-2020 online course completed pre- and postevaluations assessing anatomy and radiology knowledge, contouring skills, self-confidence, and course satisfaction.There were 180 individuals enrolled (F2F: n = 40; online: n = 140); 57 participants (F2F: n = 30; online: n = 27) completed both evaluations. The online course had a wider geographic participation (19 countries) than F2F (4 countries). F2F had primarily RO resident participation (80%), compared with online (41%). Both cohorts demonstrated similar improvements in self-confidence pertaining to anatomy and radiology knowledge, contouring skills, and interpreting radiology images (all P.001). Both the online (mean ± SD improvement: 6.6 ± 6.7 on a 40-point scale; P.001) and F2F (3.7 ± 5.7; P = .002) groups showed anatomy and radiology knowledge improvement. Only the F2F group demonstrated improvement with the contouring assessment (F2F: 0.10 ± 0.17 on a 1-point Dice scale; P = .004; online: 0.07 ± 0.16; P = .076). Both cohorts perceived the course as a positive experience (F2F: 4.8 ± 0.4 on a 5-point scale; online: 4.5 ± 0.6), stated it would improve their professional practice (F2F: 4.6 ± 0.5; online: 4.2 ± 0.8), and said they would recommend it to others (F2F: 4.8 ± 0.4; online: 4.4 ± 0.6).The online ARC Bootcamp demonstrated improved self-confidence, knowledge scores, and high satisfaction levels among participants. The offering had lower completion rates but was more accessible to geographic regions, provided a flexible learning experience, and allowed for ongoing education during the COVID-19 pandemic.

Purpose/objectives High dose rate (HDR) interstitial brachytherapy (ISBT) boost is integral for definitive radiation treatment of primary vaginal cancer. Technological advances with CT or MRI guidance provide improved precision and ability to treat more extensively invasive tumors over historical techniques, but reported experience is limited. We sought to provide updated outcome and toxicity data for women with primary vaginal cancer undergoing treatment with a modern ISBT technique. Material/methods Databases of primary vaginal carcinoma patients treated at two Canadian academic cancer institutions were combined including patient, tumor and treatment characteristics, and survival outcomes and toxicity data. Descriptive statistics, survival estimates based on the Kaplan-Meier method, and univariable/multivariable Cox proportional hazards regression analyses are reported. Results Between 2002 and 2017, 67 women with primary vaginal cancer were treated with 3D HDR ISBT. FIGO stage distribution was I (22.4%), II (50.8%), III (17.9%), IVa (9.0%). All patients received external beam radiotherapy and HDR ISBT of 500–750 cGy per fraction over 2–4 fractions. Median follow-up was 2.68 years (95% confidence interval: 2.04–6.04). Cumulative rate of grade 3–4 genitourinary/gastrointestinal toxicity was 10.4%. Four patients developed vaginal fistula. Progression-free survival at 2 and 3 years was 73.5% and 66.4% for all patients, 78.3% and 75.0% for stage I-II and 61.6% and 46.2% for stage III-IVa, respectively (log-rank p = 0.252). Conclusions Use of 3D image-guided HDR ISBT boost was safe and resulted in improved survival outcomes compared to historical rates in this series of primary vaginal cancer patients. Prospective study is warranted to better define clinical and dosimetric predictors of local control.

The purpose of this study was to evaluate the use of a semiautomatic algorithm to simultaneously segment multiple high-dose-rate (HDR) gynecologic interstitial brachytherapy (ISBT) needles in three-dimensional (3D) transvaginal ultrasound (TVUS) images, with the aim of providing a clinically useful tool for intraoperative implant assessment.A needle segmentation algorithm previously developed for HDR prostate brachytherapy was adapted and extended to 3D TVUS images from gynecologic ISBT patients with vaginal tumors. Two patients were used for refining/validating the modified algorithm and five patients (8-12 needles/patient) were reserved as an unseen test data set. The images were filtered to enhance needle edges, using intensity peaks to generate feature points, and leveraged the randomized 3D Hough transform to identify candidate needle trajectories. Algorithmic segmentations were compared against manual segmentations and calculated dwell positions were evaluated.All 50 test data set needles were successfully segmented with 96% of algorithmically segmented needles having angular differences3° compared with manually segmented needles and the maximum Euclidean distance was2.1 mm. The median distance between corresponding dwell positions was 0.77 mm with 86% of needles having maximum differences3 mm. The mean segmentation time using the algorithm was30 s/patient.We successfully segmented multiple needles simultaneously in intraoperative 3D TVUS images from gynecologic HDR-ISBT patients with vaginal tumors and demonstrated the robustness of the algorithmic approach to image artifacts. This method provided accurate segmentations within a clinically efficient timeframe, providing the potential to be translated into intraoperative clinical use for implant assessment.

Cervical cancer is a deadly disease and the COVID-19 pandemic has the potential to further impact its lethality. Hypofractionated radiotherapy could mitigate this impact, however robust data in cervical cancer setting still is lacking. Information provided here could help institutions in reducing radiotherapy fractions for cervical cancer patients.

Background As new treatments and technologies have been introduced in radiation oncology, the clinical roles of radiation therapists (RTs) have expanded. However, there are few formal learning opportunities for RTs. An online, anatomy, radiology and contouring bootcamp (ARC Bootcamp) originally designed for medical residents was identified as a prospective educational tool for RTs. The purpose of this study was to evaluate an RT edition of the ARC Bootcamp on knowledge, contouring, and confidence, as well as to identify areas for future modification. Methods Fifty licensed RTs were enrolled in an eight-week, multidisciplinary, online RT ARC Bootcamp. Contouring practice was available throughout the course using an online contouring platform. Outcomes were evaluated using a pre-course and post-course multiple-choice quiz (MCQ), contouring evaluation and qualitative self-efficacy and satisfaction survey. Results Of the fifty enrolled RTs, 30 completed the course, and 26 completed at least one of the post-tests. Nineteen contouring dice similarity coefficient (DSC) scores were available for paired pre- and post-course analysis. RTs demonstrated a statistically significant increase in mean DSC scoring pooled across all contouring structures (mean ± SD improvement: 0.09 ± 0.18 on a scale from 0 to 1, p=0.020). For individual contouring structures, 3/15 reached significance in contouring improvement. MCQ scores were available for 26 participants and increased after RT ARC Bootcamp participation with a mean ± SD pre-test score of 18.6 ± 4.2 (46.5%); on a 40-point scale vs. post-test score of 24.5 ± 4.3 (61.4%) (p < 0.001). RT confidence in contouring, anatomy knowledge and radiographic identification improved after course completion (p < 0.001). Feedback from RTs recommended more contouring instruction, less in-depth anatomy review and more time to complete the course. Conclusions The RT ARC Bootcamp was an effective tool for improving anatomy and radiographic knowledge among RTs. The course demonstrated improvements in contouring and overall confidence. However, only approximately half of the enrolled RTs completed the course, limiting statistical power. Future modifications will aim to increase relevance to RTs and improve completion rates.

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.

Key Points Question What is the hemoglobin transfusion threshold and target recommended for patients with cervical cancer undergoing curative-intent radiotherapy (RT)? Findings In this international Delphi consensus study, 39 experts in gynecologic radiation oncology did not agree on a hemoglobin transfusion threshold, highlighting significant variability in clinical practice. For both external beam RT and brachytherapy, a hemoglobin transfusion target of 9 or more g/dL and less than 12 g/dL, respectively, was agreed on by an 89% consensus. Meaning A liberal packed red blood cell transfusion strategy was recommended by consensus to overcome hypoxia-induced radioresistance in patients with cervical cancer receiving curative RT., Importance Packed red blood cell (PRBC) transfusions are used to treat anemia in patients with cervical cancer undergoing radiotherapy (RT) owing to concerns of hypoxia-induced radioresistance. In the absence of high-quality evidence informing transfusion practices for patients receiving external beam RT (EBRT) and brachytherapy, various arbitrary hemoglobin target levels are used worldwide. Objective To develop consensus statements to guide PRBC transfusion practices in patients with cervical cancer receiving curative-intent RT with EBRT and brachytherapy. Design, Setting, and Participants This international Delphi consensus study was completed between November 1, 2019, and July 31, 2020. A total of 63 international clinical experts in gynecologic radiation oncology were invited; 39 (62%) accepted and consented to participate. Consensus building was achieved using a 3-round anonymous Delphi consensus method. Participants rated their agreement or disagreement with statements using a 5-point Likert scale. An a priori threshold of 75% or more was required for consensus. Main Outcomes and Measures The preplanned primary outcome of this study was to assess hemoglobin transfusion thresholds and targets for both EBRT and brachytherapy by expert consensus. Results Response rates of 100% (39 of 39), 92% (36 of 39), and 97% (35 of 36) were achieved for the first, second, and third rounds of surveys, respectively. Twenty-three experts (59%) practiced in Canada, 11 (28%) in the United States, 3 (8%) in South America, 1 (3%) in Europe, and 1 (3%) in Asia. Consensus was reached for 44 of 103 statements (43%), which were combined to form the final 27-statement consensus guideline. No specific hemoglobin transfusion threshold was agreed on by consensus for EBRT or brachytherapy. By consensus (89% [31 of 35]), a hemoglobin transfusion target for patients who receive a PRBC transfusion should be 9 g/dL or more and less than 12 g/dL. Conclusions and Relevance This study presents the first international expert consensus guideline informing PRBC transfusion practices for patients with cervical cancer undergoing EBRT and brachytherapy. A minimum hemoglobin transfusion target of 9 g/dL was endorsed to balance tumor radiosensitivity with appropriate use of a scarce resource. Randomized clinical trials are required to evaluate the optimal transfusion threshold and target that maximize clinical benefit in this patient population., This international Delphi consensus study developed consensus statements to guide packed red blood cell transfusion practices for patients with cervical cancer receiving curative-intent radiotherapy with external beam radiotherapy and brachytherapy.

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.

Brachytherapy is often used in gynecologic cancer treatment to provide high radiation doses to tumors and spare nearby healthy tissues. Intracavitary applicators, including tandem-and-ovoid and tandem-and-ring, are commonly used to position the radioactive sources appropriately. Three-dimensional (3D) transrectal ultrasound (TRUS) imaging has been demonstrated to allow for consistent delineation of the clinical target volume; however, the ability to visualize applicators and relevant structures following applicator insertion has not been investigated. We propose the use of a 3D TRUS system to visualize applicators at the time of placement. In two patient images, the key components of the tandem-and-ovoid applicators were clearly visualized, as well as the uterus, cervix, and vagina, with the potential to identify the tumor and organs-at-risk in these images. Although the tandem-and-ring applicator (one patient) obscured the cervix and anterior anatomy, the posterior applicator edges were visualized and we propose combining the 3D TRUS image with a 3D transabdominal ultrasound (TAUS) image for more complete visualization of the necessary structures. We designed a multimodality application-specific pelvic phantom to assess the feasibility of the image fusion and performed preliminary feasibility assessment on a tandem-and-ovoids applicator and a tandem-and-ring applicator with an interstitial ring cap. The resulting phantom images showed promising features for future image fusion. Intraoperative assessment of applicator placement has the potential to improve the treatment quality and reduce the risk of complications from overexposure of nearby normal tissues, as well as provides a promising approach for accessible image-guided brachytherapy, facilitating broader adoption to healthcare cost-constrained settings.

Background Patients with high-risk prostate cancer are at increased risk of lymph node metastasis and are thought to benefit from whole pelvis radiotherapy (WPRT). There has been recent interest in the use of hypofractionated radiotherapy in treating prostate cancer. However, toxicity and cancer outcomes associated with hypofractionated WPRT are unclear at this time. This phase II study aims to investigate the impact in quality of life associated with hypofractionated WPRT compared to conventionally fractionated WPRT. Methods Fifty-eight patients with unfavourable intermediate-, high- or very high-risk prostate cancer will be randomized in a 1:1 ratio between high-dose-rate brachytherapy (HDR-BT) + conventionally fractionated (45 Gy in 25 fractions) WPRT vs. HDR-BT + hypofractionated (25 Gy in 5 fractions) WPRT. Randomization will be performed with a permuted block design without stratification. The primary endpoint is late bowel toxicity and the secondary endpoints include acute and late urinary and sexual toxicity, acute bowel toxicity, biochemical failure-, androgen deprivation therapy-, metastasis- and prostate cancer-free survival of the hypofractionated arm compared to the conventionally fractionated arm. Discussion To our knowledge, this is the first study to compare hypofractionated WPRT to conventionally fractionated WPRT with HDR-BT boost. Hypofractionated WPRT is a more attractive and convenient treatment approach, and may become the new standard of care if demonstrated to be well-tolerated and effective. Trial registration This trial was prospectively registered in ClinicalTrials.gov as NCT04197141 on December 12, 2019.

We present the case of a woman diagnosed with coronavirus disease 2019 (COVID-19) while undergoing chemoradiation for locally advanced cervix cancer. This diagnosis had implications for the treatment of her cancer, and a number of important decisions had to be made. We present the issues that arose and how her oncologic care was managed.

Recent phase II clinical trials suggest that stereotactic ablative radiation therapy (SABR) can potentially improve survival for patients with oligometastatic cancer. However, these studies have mostly enrolled primaries other than gynecologic malignancies. While level I evidence is limited, recent publications exploring the use of SABR for oligometastatic gynecologic cancers have indicated a potential role for this treatment in para-aortic lymph node recurrences, and in visceral and brain metastases. The use of SABR for recurrences in the pelvis presents a number of challenges as these patients have often received previous radiation treatment. In these settings, care must be taken to avoid trespassing normal tissue tolerance with SABR leading to toxicity, especially as the potential benefit of SABR in this setting is not based on high-level evidence. Although SABR is feasible and in general safe for oligometastatic gynecologic malignancies, insufficient data are available to indicate whether it is associated with improved survival. Clinical judgment that incorporates patient and tumor factors is needed to determine if SABR is appropriate for selecting patients. Future directions include combining SABR with novel systemic therapies, determining optimal sequencing of treatments, and generating more robust randomized data pertaining to the use of SABR for oligometastatic gynecologic cancers.

Background and purpose: Declining prostate brachytherapy utilization has been reported in several studies, despite strong evidence for efficacy and safety compared to alternatives. We sought to evaluate contemporary trends in brachytherapy, external beam radiotherapy (EBRT) and prostatectomy utilization in a publicly funded healthcare system. Materials and methods: Men with localized prostate cancer diagnosed and treated between 2006 and 2017 in Ontario, Canada were identified using administrative data. Men received EBRT, brachytherapy (monotherapy or boost) or prostatectomy as initial definitive management. Multivariable logistic regression evaluated patient-, tumour-, and provider-factors on treatment utilization. Results: 61,288 men were included. On multivariable regression, the odds of receiving brachytherapy boost increased 24% per year (odds ratio [OR]:1.24, 95% CI 1.22–1.26, p < 0.01), brachytherapy monotherapy increased 3% per year (OR:1.03, 95% CI:1.02–1.04, p < 0.01), and prostatectomy declined by 6% per year (OR:0.94, 95% CI 0.93–0.95, p < 0.01). Treatment year was not significant on multivariable modelling of EBRT. In a separate multivariable model limited to those who received radiotherapy, if the first radiation oncologist seen performed brachytherapy, the OR of receiving brachytherapy monotherapy over EBRT was 5.66 (95% CI: 5.11–6.26, p < 0.01) and 2.88 (95% CI: 2.60–3.19, p < 0.01) for brachytherapy boost over EBRT alone. Substantial geographic, provider and patient variation in treatment receipt was observed. Conclusion: We found increasing brachytherapy utilization, largely driven by increasing utilization of brachytherapy boost. To our knowledge, this is the first report of increasing brachytherapy use in the era of dose escalated EBRT.

Background: Intensity modulated radiotherapy (IMRT) is increasingly being used to treat gynaecological malignancies in the postoperative setting. The purpose of this study was to evaluate the use of image-guided radiotherapy (IGRT) using cone-beam computed tomography (CBCT) with fiducial markers for daily localization. Material and methods: A single institution study was performed of consecutive cervical or endometrial cancer patients receiving adjuvant external beam radiotherapy (n = 15). Patients were set up at treatment using daily CBCT and alignment of implanted fiducial markers. Image registration was retrospectively completed based on soft tissue matching and the resulting couch shifts from each IGRT method were compared (n = 122). Results: The median shift between IGRT methods was 2 mm, 1 mm and 1 mm in the anterior-posterior (A-P), superior-inferior (S-I), and lateral directions, respectively. The largest deviations were observed in the A-P direction; however, more than 90% were within 5 mm and 63.9% were within 2.5 mm. Conclusions: IGRT based on soft tissue match provides a noninvasive convenient method for daily localization and is accurate within treatment uncertainty for the majority of cases.

PURPOSE/OBJECTIVE(S) To report the PROs of a phase III randomized trial evaluating TAS combined with dose-escalated RT for patients with intermediate risk prostate cancer. MATERIALS/METHODS Eligible patients had intermediate risk prostate cancer defined as harboring ≥ 1 of these risk factors: clinical stage T2b-T2c, Gleason score 7, or PSA > 10 to ≤ 20 ng/mL. Patients were randomized to dose-escalated RT alone (Arm 1) or RT plus TAS (Arm 2) consisting of LHRH agonist/antagonist with oral antiandrogen for 6 months. Validated PROs included the Expanded Prostate Cancer Index Composite (EPIC-50) and Patient-Reported Outcome Measurement Information System (PROMIS) Fatigue short form. PRO change scores, calculated for each patient as the follow-up score minus baseline score (at end of RT, 6, 12, and 60 months from start of RT) were compared between treatment arms using a two-sample t test. An effect size (ES) of 0.50 SD (standard deviation) of the baseline measure was considered clinically meaningful. For the PRO sample size, 200 patients per arm would provide 90% statistical power to detect an ES < 0.50 if the completion rate was only 60%. Mixed effect regression models were also utilized. Clinical outcomes are reported in a separate abstract. RESULTS Of the 402 initial planned subset of trial patients who completed baseline PROs, PRO compliance was approximately 96%, 89%, 86% and 87% at end of RT, 6, 12 and 60 months, respectively. There were no significant differences between these 402 patients and the remaining patients on this trial with respect to age, race, performance status, # risk factors, or comorbidity score. While EPIC urinary and bowel scores decreased significantly by the end of RT in both arms, no clinically meaningful differences between arms were detected over time. For the EPIC hormonal and sexual domains, however, there were clinically meaningful differences between the two arms with greater (P < 0.0001) deficits in the RT + TAS arm. These differences improved over time, with ∼50% resolution by one year after treatment and no clinically meaningful differences by 5 years between arms. PROMIS-fatigue scores increased from baseline in both arms and were significantly higher in arm 2 at the end of RT (P = 0.016), though slightly lower at 12 and 60 months. CONCLUSION The addition of TAS to dose-escalated RT demonstrated significant clinically meaningful declines in the EPIC hormonal and sexual domains, and increases in the PROMIS-fatigue scores, compared to RT alone. These scores gradually improved over time, with no clinically meaningful differences between arms in fatigue by one year, or in hormonal and sexual domains by 5 years. Beyond the clinical outcomes, these PRO results directly from patients provide added value to help patients make informed decisions among treatment options.

During high-dose-rate (HDR) interstitial brachytherapy of gynecologic malignancies, precise placement of multiple needles is necessary to provide optimal dose to the tumor while avoiding overexposing nearby healthy organs, such as the bladder and rectum. Needles are currently placed based on preoperative imaging and clinical examination but there is currently no standard for intraoperative image guidance. We propose the use of a three-dimensional (3D) ultrasound (US) system incorporating three scanning geometries: 3D transrectal US (TRUS), 360° 3D sidefire transvaginal US (TVUS), and 3D endfire TVUS, to provide an accessible and versatile tool for intraoperative image guidance during interstitial gynecologic brachytherapy. Images are generated in 12 - 20 s by rotating a conventional two-dimensional US probe, providing a reconstructed 3D image immediately following acquisition. Studies of needles in patient images show mean differences in needle positions of 3.82 ± 1.86 mm and 2.36 ± 0.97 mm in TRUS and sidefire TVUS, respectively, when compared to the clinical x-ray computed tomography (CT) images. A proof-of-concept phantom study of the endfire TVUS mode demonstrated a mean positional difference of 1.91 ± 0.24 mm. Additionally, an automatic needle segmentation tool was tested on a 360° 3D TVUS patient image resulting in a mean angular difference of 0.44 ± 0.19 ° and mean positional difference of 0.78 ± 0.17 mm when compared to manually segmented needles. The implementation of 3D US image guidance during HDR interstitial gynecologic brachytherapy provides a versatile intraoperative system with the potential for improved implant quality and reduced risk to nearby organs.

e17608 Background: A worldwide decline in prostate brachytherapy (BT) utilization has been reported in multiple health care settings/jurisdictions, despite strong evidence for efficacy and safety compared to other alternatives. We sought to evaluate contemporary trends in BT, EBRT and prostatectomy utilization in a publicly funded healthcare system. Methods: Men with localized prostate cancer diagnosed and treated between 2007 and 2017 in Ontario, Canada were identified using administrative data from the Institute for Clinical Evaluative Sciences. Men were coded to have received EBRT, BT (monotherapy or boost) or prostatectomy as initial definitive management. Trends were evaluated using the Cochran-Armitage test. Multivariate logistic regression was used to evaluate patient-, tumour-, and provider-factors on treatment utilization over time. Results: 57,655 men were included in our study. Prostate BT use increased from 7.5% of all treatments in 2007 to 15.4% in 2017 ( p< 0.01), primarily due to increased use of BT boost (1.7% in 2007 to 10.4% in 2017, p < 0.01). Relative to EBRT, BT use increased from 17.9% in 2007 to 28.1% in 2017 ( p< 0.01). On multivariate analysis (MVA), BT boost use increased by 28% per year (OR 1.28, 95% CI 1.26–1.31, p< 0.01) and BT monotherapy use increased by 12% per year (OR 1.12, 95% CI 1.10–1.14, p< 0.01), offset by decreasing prostatectomy use (12% per year, OR 0.88, 95% CI 0.87–0.89, p< 0.01). Comparing BT to EBRT, the strongest predictors of receiving BT were geographic residence (OR 27.6, 95% CI: 20.3–37.6, p< 0.01 between highest/lowest Local Health Integration Networks) and whether the first consulting radiation oncologist performed BT (OR 3.46, 95% CI: 3.15–3.80, p< 0.01). Other significant factors predicting BT use vs. EBRT included lower age, lower PSA, lower Charlson comorbidity score and increasing neighborhood income quintile. Low-intermediate, high-intermediate and high-risk groups were predictive of receiving BT boost, whereas BT monotherapy was predominantly used in low-risk disease. Conclusions: Contrary to trends observed in other jurisdictions, utilization of prostate BT is increasing over time in Ontario. However, substantial variation in BT utilization was found, strongly driven by both geographic region and radiation oncologist BT practice patterns. To our knowledge, this is the first study to report increasing BT utilization in the era of dose-escalated EBRT, with Ontario potentially serving as a model to promote BT utilization elsewhere.

Brachytherapy, a type of radiotherapy, may be used to place radioactive sources into or in close proximity to tumors, providing a method for conformally escalating dose in the tumor and the local area surrounding the malignancy. High-dose-rate interstitial brachytherapy of vaginal tumors requires precise placement of multiple needles through holes in a plastic perineal template to deliver treatment while optimizing dose and avoiding overexposure of nearby organs at risk (OARs). Despite the importance of needle placement, image guidance for adaptive, intraoperative needle visualization, allowing misdirected needles to be identified and corrected during insertion, is not standard practice. We have developed a 360-deg three-dimensional (3-D) transvaginal ultrasound (TVUS) system using a conventional probe with a template-compatible custom sonolucent vaginal cylinder and propose its use for intraoperative needle guidance during interstitial gynecologic brachytherapy. We describe the 3-D TVUS mechanism and geometric validation, present mock phantom procedure results, and report on needle localization accuracy in patients. For the six patients imaged, landmark anatomical features and all needles were clearly visible. The implementation of 360-deg 3-D TVUS through a sonolucent vaginal cylinder provides a technique for visualizing needles and OARs intraoperatively during interstitial gynecologic brachytherapy, enabling implants to be assessed and providing the potential for image guidance.

Aims Recurrent gynaecological tumours can cause significant morbidity with limited salvage options. This study investigates the strategy of salvage single-modality interstitial brachytherapy (SM-ISBT) for recurrent gynaecological pelvic cancer at two specialised ISBT centres. Materials and methods Patients who had received salvage SM-ISBT for pelvic recurrence of gynaecological cancers from September 2008 to January 2017 were included. None had distant metastasis at the time of recurrence. Local control, progression-free and overall survival and long-term toxicities were evaluated. Results Twenty-six patients with a median follow-up of 24 months (range 2.5–106.3 months) after SM-ISBT were included. Primary cancer sites were endometrium (20), cervix (4), vulva (1) and vagina (1). All patients had prior whole-pelvic external beam irradiation and 16 had prior brachytherapy. The median disease-free survival prior to SM-ISBT was 20.3 months (interquartile range 9.9–30.5). SM-ISBT was delivered with high dose rate technique over three to six fractions. The median high-risk clinical target volume was 34.6 cm3, with a median D90 of 29.1 Gy (range 16.1–64.6). The median bladder, rectum and sigmoid D2cm3 were 15.5, 18.7 and 3.7 Gy, respectively. After SM-ISBT, complete and partial responses were achieved in 17 (64%) and 5 (19%) patients, respectively. Two (7.4%) patients had grade 3 toxicities (both vaginal stenosis), with no grade 4 complications. Eighteen patients (69%) recurred, including local, regional and metastatic in 14 (54%), 8 (30%) and 5 (19%) patients, respectively. Two-year local control, progression-free survival and overall survival were 50, 38 and 78%, respectively. In follow-up, 12 patients (46%) remained in local control. Conclusions Salvage SM-ISBT re-irradiation for pelvic recurrence of gynaecological malignancies was feasible and safe. With limited salvage options, the local control obtained in more than a quarter of patients seems reasonable. Further efforts are needed to establish a consensus about the optimal patient selection, dose fractionation, implant technique and combination with systemic therapies.

In high-dose-rate (HDR) interstitial gynecologic brachytherapy, needles are positioned into the tumor and surrounding area through a template to deliver radiotherapy. Optimal dose and avoidance of nearby organs requires precise needle placement; however, there is currently no standard method for intra-operative needle visualization or guidance. We have developed and validated a 360° three-dimensional (3D) transvaginal ultrasound (TVUS) system and created a sonolucent vaginal cylinder that is compatible with the current template to accommodate a conventional side-fire ultrasound probe. This probe is rotated inside the hollow sonolucent cylinder to generate a 3D image. We propose the use of this device for intra-operative verification of brachytherapy needle locations. In a feasibility study, the first ever 360° 3D TVUS image of a gynecologic brachytherapy patient was acquired and the image allowed key features, including bladder, rectum, vaginal wall, and bowel, to be visualized with needles clearly identifiable. Three patients were then imaged following needle insertion (28 needles total) and positions of the needles in the 3D TVUS image were compared to the clinical x-ray computed tomography (CT) image, yielding a mean trajectory difference of 1.67 ± 0.75°. The first and last visible points on each needle were selected in each modality and compared; the point pair with the larger distance was selected as the maximum difference in needle position with a mean maximum difference of 2.33 ± 0.78 mm. This study demonstrates that 360° 3D TVUS may be a feasible approach for intra-operative needle localization during HDR interstitial brachytherapy of gynecologic malignancies.

Objective As the optimal adjuvant management of stage IA serous or clear cell endometrial cancer is controversial, a multi-institutional review was conducted with the objective of evaluating the appropriateness of various strategies including observation. Methods Retrospective chart reviews for 414 consecutive patients who underwent hysterectomy for FIGO stage IA endometrial cancer with serous, clear cell or mixed histology between 2004 and 2015 were conducted in 6 North American centers. Time-to-event outcomes were analyzed by Kaplan-Meier estimates, log-rank test, univariable and multivariable cox proportional hazard regression models. Results Post-operative management included observation (50%), chemotherapy and radiotherapy (RT) (27%), RT only (16%) and chemotherapy only (7%). The 178 RT patients received external beam (EBRT, 16%), vaginal vault brachytherapy (VVB, 56%) or both (28%). Among patients without any adjuvant treatment, 5-year local control (LC), disease free survival (DFS) and cancer-specific survival (CSS) were 82% (95% confidence interval: 74–88), 70% (62–78) and 90% (82–94), respectively. CSS in patients without adjuvant treatment was improved with adequate surgical staging (100% vs. 87% (77–92), log-rank p=0.022). Adjuvant VVB was associated with improved LC (5-year 96% (91–99) vs. 84% (76–89), log-rank p=0.007) and DFS (5-year 79% (66–88) vs. 71% (63–77), log-rank p=0.033). Adjuvant chemotherapy was associated with better LC (5-year 96% (90–98) vs. 84% (77–89), log-rank p=0.014) and DFS (5-year 84% (74–91) vs. 69% (61–76), log-rank p=0.009). On multivariable analysis, adjuvant chemotherapy and VVB were associated with improved LC while adjuvant chemotherapy and age were significant for DFS. Conclusions In stage IA serous or clear cell uterine cancer, adjuvant RT and chemotherapy were associated with better LC and DFS. Observation may be appropriate in patients who have had adequate surgical staging.

Purpose To measure the accuracy and variability of manual high-dose-rate (HDR) prostate brachytherapy (BT) needle tip localization using sagittally reconstructed three-dimensional (3D) transrectal ultrasound (TRUS) augmented with live two-dimensional (2D) sagittal TRUS. Methods and Materials Ten prostate cancer patients underwent HDR-BT during which the sagittally assisted sagittally reconstructed (SASR) segmentation technique was completed in parallel with commercially available sagittally assisted axially reconstructed (SAAR) TRUS for comparison. The SASR technique makes use of live 2D ultrasound intraoperatively and allows needle tip updates using the final 3D image in the absence of image artifacts. These updates were repeated offline twice by two separate users. Needle end-length measurements were used to calculate insertion depth errors (IDEs) for each technique. Results Images of 147 needles were analyzed. For the SASR technique, both users were confident in tip positions on the final 3D image within 3 mm for 52% of needles, so these tip positions were updated. For the remaining 48% of needles, the tip positions from the live 2D images were used. This SASR technique enabled the localization of all needles with IDEs within ±3 mm for 84% of needles and IDE range of [−6.2 mm, 5.9 mm], compared with 57% and [−8.1 mm, 7.7 mm] when using the commercially available SAAR technique. Conclusions The SASR technique mitigates the impact of 3D TRUS image artifacts on HDR-BT needle tip localization by incorporating live 2D sagittal TRUS intraoperatively and provides a statistically significant reduction in IDE variance compared with the routine SAAR technique.

Purpose Limited therapeutic options are available for the treatment of locally recurrent endometrial carcinoma. Our objective was to report an institutional experience using interstitial brachytherapy (IBT) to treat significant recurrent endometrial carcinoma, including previously irradiated disease. Methods and materials Between December 2004 and September 2012, 40 patients with high-volume locally recurrent endometrial cancer were treated by high-dose-rate IBT (± external beam radiation therapy EBRT). Sixteen patients had prior radiotherapy: EBRT alone (n = 5), intracavitary brachytherapy alone (n = 3), or EBRT with intracavitary brachytherapy boost (n = 8). Actuarial outcome rates were calculated using the Kaplan–Meier method and compared using the log-rank test. Results Median followup interval was 18 months. Median disease-free interval was 61 months. Actuarial local control, progression-free survival (PFS), and overall survival were 74% and 60%, 70% and 51%, and 83% and 72% at 12 and 24 months, respectively. p-Values for local control, progression-free survival, and overall survival between patient who had prior RT (n = 16) to no prior RT (n = 24) were p = 0.38, 0.32, and 0.90, respectively. Acute toxicities include Grade 1–2 pain (5%), genitourinary (7%), gastrointestinal (12%), soft tissue (5%), and dermatologic (12%). Four patients observed late Grade 3–4 toxicities, including rectal bleeding/fistula and soft tissue necrosis. Conclusions High-dose-rate IBT is an effective treatment for locally recurrent endometrial carcinoma with an acceptable toxicity profile. Outcomes are similar between previously irradiated and nonirradiated patients. In women who have received prior radiotherapy and are often considered for palliative treatment, interstitial brachytherapy is a potentially curative option.

Objectives The adjuvant treatment of early stage IA serous and clear cell carcinomas of the uterus is controversial. The aims of the study were to report on a single institution experience treating these high-risk early uterine cancers and to identify women who may be suitable for observation alone. Methods and Materials A retrospective review of patients presenting from 2003 to 2013 with pathologic stage IA (International Federation of Gynecology and Obstetrics 2009) serous or clear cell uterine carcinoma was performed. Patient and disease characteristics, surgical staging, treatment details, and recurrence data were collected. Recurrence rates and 5-year actuarial estimates of recurrence free survival (RFS) were the primary outcomes of interest. Results A total of 77 patients with stage IA were identified. Median (range) follow-up was 34 (1–108) months. Staging lymphadenectomy was performed in 83%. Adjuvant treatment was given to 27 patients, whereas 50 underwent observation. There were 12 recurrences total, with the 5-year RFS 79% for the cohort, with no statistically significant difference between observation and adjuvant treatment. Only 4 patients received adjuvant chemotherapy and none recurred. In the observation cohort, the presence versus absence of myometrial invasion showed a trend to poorer 5-year RFS (75% vs 93%, P = 0.06). Conclusions Observation seems to be a valid strategy in those patients with stage IA serous and clear cell carcinoma without myometrial invasion. The presence of any myometrial invasion may confer a higher risk of recurrence, although further studies are needed to determine the optimal adjuvant treatment regimen.

Introduction: The Consolidated Standards for Reporting Trials (CONSORT) checklist has been formulated to improve the reporting of randomized controlled trials (RCTs). This investigation aims to determine predictors of CONSORT checklist compliance in the oncology literature. Methods: Eight-hundred and fifty articles assessing interventions in adult breast, prostate, colorectal, and lung cancer between 1992-2010 were identified by a systematic search. Exclusion criteria included investigations reporting interim/secondary/long-term update analyses, pilot/phase 2/non-parallel design studies. After full article review, 408 RCTs were eligible for inclusion. RCT descriptive variables including number of authors/study patients, 2009 journal impact factor/journal classification, type of cancer and therapeutic intervention, publication year, primary study country, and cooperative group involvement were captured for all trials. Two qualified auditors assessed all manuscripts in order to generate average and difference CONSORT checklist scores related to the observers. Results: Mean average CONSORT score was 16.6 (SD 3, max 25) and median difference score was two (interquartile range one to three). Kappa agreement for each checklist item ranged from (0.02-0.92) with an overall two-way intra-class correlation coefficient of 0.71 (95% Cl: 0.61-0.78) for comparison of overall CONSORT score between raters. Recent year of publication, increasing author number, and higher impact factor were associated with higher average CONSORT scores (p

6126 Background: The Consolidated Standards for Reporting Trials (CONSORT) checklist has been formulated to improve the reporting of randomized controlled trials (RCTs). The purpose of this investigation is to determine predictors of CONSORT checklist compliance in the oncology literature over the past two decades. Methods: Eight-hundred and fifty parallel two-arm RCTs assessing oncological interventions in adult breast, prostate, colorectal, and lung cancer between 1992-2010 were identified by a systematic search of the medical literature. Exclusion criteria included investigations reporting interim/secondary/long-term update analyses, pilot/phase 2 studies and studies not employing a parallel design. After full article review, 408 articles were eligible for inclusion into the CONSORT audit database. RCT descriptive variables including number of authors/study patients, 2009 journal impact factor/journal classification, type of cancer and therapeutic intervention, publication year, primary study country, ...

Background Increasing use of IMRT to treat breast and prostate cancers at high risk of regional nodal spread relies on accurate contouring of targets and organs at risk, which is subject to significant inter- and intra-observer variability. This study sought to evaluate the performance of an atlas based deformable registration algorithm to create multi-patient CT based atlases for automated contouring. Methods Breast and prostate multi-patient CT atlases (n = 50 and 14 respectively) were constructed to be consistent with RTOG consensus contouring guidelines. A commercially available software algorithm was evaluated by comparison of atlas-predicted contours against manual contours using Dice Similarity coefficients. Results High levels of agreement were demonstrated for prediction of OAR contours of lungs, heart, femurs, and minor editing required for the CTV breast/chest wall. CTVs generated for axillary nodes, supraclavicular nodes, prostate, and pelvic nodes demonstrated modest agreement. Small and highly variable structures, such as internal mammary nodes, lumpectomy cavity, rectum, penile bulb, and seminal vesicles had poor agreement. Conclusions A method to construct and validate performance of CT-based multi-patient atlases for automated atlas based auto-contouring has been demonstrated, and can be adopted for clinical use in planning of local regional breast and high-risk prostate radiotherapy.