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The aim of this study was to evaluate the rate of axillary node–positive disease in patients with early breast cancer who had a suspicious axillary lymph node on radiation planning computed tomography (CT). A retrospective review was conducted of the medical records of all patients with breast cancer who were referred for axillary ultrasound from the radiation unit to the breast imaging unit at the Meirav Breast Center, Sheba Medical Center, from 2012 to 2022. Ethics approval was obtained. Only the records of patients who were referred due to an abnormal axillary lymph node seen on radiation planning CT were further evaluated. During the study period, a total of 21 patients were referred to the breast imaging unit for evaluation of suspicious nodes seen on radiation planning CT. Of these, 3 cases were excluded. A total of 15 out of the 18 (83%) patients included had an abnormal lymph node in the ultrasound, and an ultrasound-guided biopsy was recommended (BI-RADS 4). Of these, 3 (out of 15, 20%) had a positive biopsy for tumor cells from the axillary lymph node. Two were cases after primary systemic therapy without complete pathologic response. Thickening of the lymph node cortex and complete loss of the central fatty hilum were associated with pathologic lymph node. Sonar had limited ability to differentiate reactive nodes from involved nodes. The presence of lymph nodes with loss of cortical-hilum differentiation on ultrasound together with clinical features are parameters that can help guide the need of further biopsy. Histopathology evaluation is important to make the diagnosis of residual axillary disease. Future studies and guidelines are needed to improve the diagnostic abilities and reduce the number of patients who are undergoing biopsy for noninvolved nodes. [ABSTRACT FROM AUTHOR]

The number of Canadians diagnosed with cancer, and subsequent demand for radiation therapy, are expected to increase over time. This study aimed to update our needs-based workforce planning model to ensure appropriate staffing levels in the future. The supply of radiation oncologists, by age group, sex, and full-time equivalent status, was projected from 2020 to 2040 using a recursive-aging, input-output model developed with seeding parameters derived from national sources. The demand for radiation oncologists until 2040 was estimated using referral patterns for radiation therapy and consultation workload metrics applied to projected annual cancer incident cases to calculate required full-time equivalent positions. Baseline model parameters were also applied to the 2005-2019 workforce and incident case data to evaluate preprojection supply and demand trends. Preprojection trends for 2005 to 2019 revealed accelerated staffing growth that transitioned from a workforce shortage to a surplus state in 2014 followed by substantial growth slowdown in 2016. The model predicts a transient surplus of radiation oncologists until 2026 followed by a projected deficit in subsequent years. Sensitivity analyses using the plausible range for each parameter continued to favor an undersupply, suggesting a trainee shortage unable to meet workforce expansion needs. Considering possible future declining trends in radiotherapy utilization and workload, calculations to inform corrective efforts in resident numbers resulted in 25 entry positions per year, up from 21 per year currently. Geographic distribution of trainees, relative to workforce and cancer incidence distributions, could be improved with more residency positions in Canadian regions outside Ontario. Demand for radiation therapy and radiation oncologists in Canada are expected to grow more quickly than future expansion in staffing levels. Our workforce planning model provides evidence for more trainee requirements to inform stakeholders of possible corrective actions to training programs and recruitment. Further research is needed to explore additional strategies to expand capacity and high-quality delivery of radiation therapy to meet the foreseeable increase in Canadian patients with cancer. [ABSTRACT FROM AUTHOR]

The Pediatric Normal Tissue Effects in the Clinic (PENTEC) consortium has made significant contributions to understanding and mitigating the adverse effects of childhood cancer therapy. This review addresses the role of diagnostic imaging in detecting, screening, and comprehending radiation therapy–related late effects in children, drawing insights from individual organ-specific PENTEC reports. We further explore how the development of imaging biomarkers for key organ systems, alongside technical advancements and translational imaging approaches, may enhance the systematic application of imaging evaluations in childhood cancer survivors. Moreover, the review critically examines knowledge gaps and identifies technical and practical limitations of existing imaging modalities in the pediatric population. Addressing these challenges may expand access to, minimize the risk of, and optimize the real-world application of, new imaging techniques. The PENTEC team envisions this document as a roadmap for the future development of imaging strategies in childhood cancer survivors, with the overarching goal of improving long-term health outcomes and quality of life for this vulnerable population. [ABSTRACT FROM AUTHOR]

The development of normal tissue radiation dose-response models for children with cancer has been challenged by many factors, including small sample sizes; the long length of follow-up needed to observe some toxicities; the continuing occurrence of events beyond the time of assessment; the often complex relationship between age at treatment, normal tissue developmental dynamics, and age at assessment; and the need to use retrospective dosimetry. Meta-analyses of published pediatric outcome studies face additional obstacles of incomplete reporting of critical dosimetric, clinical, and statistical information. This report describes general methods used to address some of the pediatric modeling issues. It highlights previous single- and multi-institutional pediatric dose-response studies and summarizes how each PENTEC taskforce addressed the challenges and limitations of the reviewed publications in constructing, when possible, organ-specific dose-effect models. [ABSTRACT FROM AUTHOR]

Pediatric Normal Tissue Effects in the Clinic (PENTEC) is an international multidisciplinary effort that aims to summarize normal-tissue toxicity risks based on published dose-volume data from studies of children and adolescents treated with radiation therapy (RT) for cancer. With recognition that children are uniquely vulnerable to treatment-related toxic effects, our mission and challenge was to assemble our group of physicians (radiation and pediatric oncologists, subspecialists), physicists with clinical and modeling expertise, epidemiologists, and other scientists to develop evidence-based radiation dosimetric guidelines, as affected by developmental status and other factors (eg, other cancer therapies and host factors). These quantitative toxicity risk estimates could serve to inform RT planning and thereby improve outcomes. Tandem goals included the description of relevant medical physics issues specific to pediatric RT and the proposal of dose-volume outcome reporting standards to inform future studies. We created 19 organ-specific task forces and methodology to unravel the wealth of data from heterogeneous published studies. This report provides a high-level summary of PENTEC's genesis, methods, key findings, and associated concepts that affected our work and an explanation of how our findings may be interpreted and applied in the clinic. We acknowledge our predecessors in these efforts, and we pay homage to the children whose lives informed us and to future generations who we hope will benefit from this additional step in our path forward. [ABSTRACT FROM AUTHOR]

Clinical trial participation continues to be low, slowing new cancer therapy development. Few strategies have been prospectively tested to address barriers to enrollment. We investigated the effectiveness of a physician audit and feedback report to improve clinical trial enrollment. We conducted a randomized quality improvement study among radiation oncologists at a multisite tertiary cancer network. Physicians in the intervention group received quarterly audit and feedback reports comparing the physician's trial enrollments with those of their peers. The primary outcome was trial enrollments. Among physicians randomized to receive the feedback report (n = 30), the median proportion of patients enrolled during the study period increased to 6.1% (IQR, 2.6%-9.3%) from 3.2% (IQR, 1.1%-10%) at baseline. Among those not receiving the feedback report (n = 29), the median proportion of patients enrolled increased to 4.1% (IQR, 1.3%-7.6%) from 1.6% (IQR, 0%-4.1%) at baseline. There was a nonsignificant change in the proportion of enrollments associated with receiving the feedback report (−0.6%; 95% CI, −3.0% to 1.8%; P =.6). Notably, there was an interaction between baseline trial accrual and receipt of feedback reports (P =.005), with enrollment declining among high accruers. There was an increase in enrollment throughout the study, regardless of study group (P =.001). In this study, a positive effect of physician audit and feedback on clinical trial enrollment was not observed. Future efforts should avoid disincentivizing high accruers and might consider pairing feedback with other patient- or physician-level strategies. The increase in trial enrollment in both groups over time highlights the importance of including a comparison group in quality improvement studies to reduce confounding from secular trends. [ABSTRACT FROM AUTHOR]

Fatigue is among the most common but most poorly understood radiation therapy–associated toxicities. This prospective study sought to investigate whether cardiorespiratory fitness, an integrative measure of whole-body cardiopulmonary function, is associated with patient-reported fatigue in women with early-stage breast cancer undergoing radiation therapy. Patients with stage Tis-T2N0M0 breast cancer and an Eastern Cooperative Oncology Group performance status of 0 to 1 undergoing breast radiation therapy performed a symptom-limited cardiopulmonary exercise test (CPET) on a motorized treadmill to assess cardiorespiratory fitness as measured by peak oxygen uptake (VO 2 peak). Fatigue was assessed using the Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue Scale. Both assessments were performed during or immediately after radiation therapy completion. All patients were treated with an opposed tangent technique to a dose of 4240 cGy in 16 fractions with or without a lumpectomy bed boost. Patients receiving cytotoxic chemotherapy were excluded. Pearson correlation coefficients and univariate linear regression were used to assess associations amongVO 2 peak, fatigue, and patient characteristics. Twenty-eight patients (median age, 52 years; range, 31-71) completed a CPET and FACIT-Fatigue assessment. Median VO 2 peak was 25.1 mL O 2 .kg–1.min–1 (range, 16.7-41.7). The majority of patients (78.6%) displayed a VO 2 peak lower than their age-predicted VO 2 peak. Both age and body mass index were significantly associated with VO 2 peak levels. The median FACIT-Fatigue score was 41.5 (range, 10-52), with lower values indicating more fatigue. VO 2 peak was not significantly associated with FACIT-Fatigue score (P =.20). VO 2 peak was not a significant predictor of radiation therapy–related fatigue. Most patients with breast cancer had marked impairments in cardiorespiratory fitness as determined by VO 2 peak. Larger prospective studies are needed to further investigate this novel finding and evaluate the effects of interventions aimed at improving cardiorespiratory fitness and their ability to potentially prevent fatigue. [ABSTRACT FROM AUTHOR]

There is currently no gold standard for the management of acute radiation enteritis. We compared the efficacy and safety of Racecadotril, an anti-hypersecretory drug, versus Loperamide, an anti-motility agent, in acute radiation enteritis. We conducted a randomized, double-masked, non-inferiority trial at a single research institute. Patients receiving curative radiation for pelvic malignancies, who developed grade 2 or 3 diarrhea (as per Common Terminology Criteria for Adverse Events, v 4.0) were included in the study. Patients in the intervention arm received Racecadotril and placebo. Patients in the control arm received Loperamide and placebo. The primary outcome was the resolution of diarrhea, 48 hours after the start of treatment. 162 patients were randomized between 2019 and 2022. On intention-to-treat analysis, 68/81 patients, 84%, (95% CI, 74.1%-91.2%) in the Racecadotril arm and 70/81, 86.4%, (95% CI, 77.0%-93.0%) in the Loperamide arm improved from grade 2 or 3 diarrhea to grade 1 or 0, (P =.66, χ2 test). The difference in proportion was 2.4% (95% CI: –8.5% to 13.4%). Since the upper boundary of the 95% CI crossed our non-inferiority margin of 10% (13.4%) we could not prove the non-inferiority of Racecadotril over Loperamide. Rebound constipation was more in the Loperamide arm compared to Racecadotril (17.3% vs 6.2%; P =.028) The non-inferiority of Racecadotril to Loperamide in acute radiation enteritis could not be demonstrated. However, Racecadotril can be the preferred drug of choice in acute radiation enteritis because Racecadotril does not affect bowel motility, achieved a high clinical success rate similar to that of Loperamide, and was associated with lesser side effects. [ABSTRACT FROM AUTHOR]

The statistical technique of multiple regression, commonly referred to as "multivariable regression," is often used in clinical research to quantify the relationships between multiple predictor variables and a single outcome variable of interest. The foundational theory underpinning multivariable regression assumes that all predictor variables are independent of one another. In other words, the effect of each independent variable is measured by its contribution to the regression equation while all other variables remain unchanged. In the presence of correlations between two or more variables, however, it is impossible to change one variable without a consequent change in the variable(s) it is linked to. This condition, known as "multicollinearity," can introduce errors into multivariable regression models by affecting estimates of the regression coefficients that quantify the relationship between individual predictor variables and the outcome variable. Errors that arise due to violations of the multicollinearity assumption are of special interest to radiation oncology researchers. Because of high levels of correlation among variables derived from points along individual organ dose-volume histogram (DVH) curves, as well as strong intercorrelations among dose-volume parameters in neighboring organs, dosimetric analyses are particularly subject to multicollinearity errors. For example, dose-volume parameters for the heart are strongly correlated not only with other points along the heart DVH curve but are likely also correlated with dose-volume parameters in neighboring organs such as the lung. In this paper, we describe the problem of multicollinearity in accessible terms and discuss examples of violations of the multicollinearity assumption within the radiation oncology literature. Finally, we provide recommendations regarding best practices for identifying and managing multicollinearity in complex data sets. [ABSTRACT FROM AUTHOR]

PurposeNumerous publications during the COVID-19 pandemic recommended the use of hypofractionated radiation therapy. This project assessed aggregate changes in the quality of the evidence supporting these schedules to establish a comprehensive evidence base for future reference and highlight aspects for future study.Methods and materialsBased on a systematic review of published recommendations related to dose fractionation during the COVID-19 pandemic, 20 expert panelists assigned to 14 disease groups named and graded the highest quality of evidence schedule(s) used routinely for each condition and also graded all COVID-era recommended schedules. The American Society for Radiation Oncology quality of evidence criteria were used to rank the schedules. Process-related statistics and changes in distributions of quality ratings of the highest-rated versus recommended COVID-19 era schedules were described by disease groups and for specific clinical scenarios.ResultsFrom January to May 2020 there were 54 relevant publications, including 233 recommended COVID-19-adapted dose fractionations. For site-specific curative and site-specific palliative schedules, there was a significant shift from established higher-quality evidence to lower-quality evidence and expert opinions for the recommended schedules (P = .022 and P < .001, respectively). For curative-intent schedules, the distribution of quality scores was essentially reversed (highest levels of evidence "pre-COVID" vs "in-COVID": high quality, 51.4% vs 4.8%; expert opinion, 5.6% vs 49.3%), although there was variation in the magnitude of shifts between disease sites and among specific indications.ConclusionsA large number of publications recommended hypofractionated radiation therapy schedules across numerous major disease sites during the COVID-19 pandemic, which were supported by a lower quality of evidence than the highest-quality routinely used dose fractionation schedules. This work provides an evidence-based assessment of these potentially practice-changing recommendations and informs individualized decision-making and counseling of patients. These data could also be used to support radiation therapy practices in the event of second waves or surges of the pandemic in new regions of the world.

Many medical schools in the United States have affiliated pathway, preparatory, and/or prematriculation programs that enroll a high percentage of students historically underrepresented in medicine (URiM). The purpose of this pilot study was to better characterize exposures to radiation oncology (RO) among students in these programs and determine the feasibility of incorporating a radiation oncologist within their pre-existing format if nonexistent. During the summers of 2021 and 2022, a radiation oncologist gave a presentation about basic principles of cancer care to 18 unique student groups in 12 premedical programs affiliated with 8 medical schools. Participating students were asked to complete an anonymous postpresentation questionnaire. Descriptive statistics are reported. A total of 467 students attended the presentations, and 241 completed the questionnaire (response rate 52.0%). The majority of participants reported being female (63.5%), URiM (66.4%), and low income (57.3%). Students were less likely to report previous teaching from a radiation oncologist (11.2%) than a surgical (17.0%) or medical oncologist (18.3%). Prior clinical shadowing with a radiation oncologist (2.9%) was also less likely than shadowing a surgical oncologist (5.0%), medical oncologist (6.6%), or any other physician (53.1%). Students were also less likely to previously believe that radiation could cure cancer (65.8%) compared with surgery (74.9%) or chemotherapy (89.3%). After the presentation, 168 students (69.7%) were more interested in a career in RO, and 211 students (87.6%) responded that the presentation was either quite or extremely valuable (median Likert-type score, 5; interquartile range, 4-5). Many of the students in premedical programs lack prior exposure to RO or knowledge of multidisciplinary cancer care, which was ameliorated by a simple yet effective presentation across a variety of different types of programs in this study. Longitudinal assessment of different types of educational initiatives and students' ultimate career trajectory will help optimize future RO initiatives among premedical URiM students. [ABSTRACT FROM AUTHOR]

Over the past decade, concerns have arisen in radiation oncology regarding potential workforce supply and demand imbalance. The American Society for Radiation Oncology commissioned an independent analysis in 2022, looking at supply and demand in the United States radiation oncology workforce and projecting future trends for 2025 and 2030. The final report, titled Projected Supply and Demand for Radiation Oncologists in the U.S. in 2025 and 2030, is now available. The analysis included evaluating radiation oncologist (RO) supply (new graduates, exits from the specialty), potential changes in demand (growth of Medicare beneficiaries, hypofractionation, loss of indications, new indications) as well as RO productivity (growth of work relative value units [wRVUs] produced), and demand per beneficiary. The results demonstrated a relative balance between radiation oncology supply and demand for radiation services; the growth in ROs was balanced by the rapid growth of Medicare beneficiaries over the same period. The primary factors driving the model were found to be growth of Medicare beneficiaries and change in wRVU productivity, with hypofractionation and loss of indication having only a moderate effect; although the most likely scenario was a balance of workforce supply and demand, scenarios did demonstrate the possibility of over- and undersupply. Oversupply may become a concern if RO wRVU productivity reaches the highest region; beyond 2030, this is also possible if growth in RO supply does not parallel Medicare beneficiary growth, which is projected to decline and will require corresponding supply adjustment. Limitations of the analysis included uncertainty regarding the true number of ROs, the lack of inclusion of most technical reimbursement and its effect as well as failing to account for stereotactic body radiation therapy. A modeling tool is available to allow individuals to evaluate different scenarios. Moving forward, continued study will be needed to evaluate trends (particularly wRVU productivity and Medicare beneficiary growth) to allow for continued assessment of workforce supply and demand in radiation oncology. [ABSTRACT FROM AUTHOR]

Disproportionate sex, racial, and ethnic diversity remains in the radiation oncology physician workforce despite widespread awareness and longitudinal efforts to improve representation. In this collaborative review, we define the rationale and components of holistic review and how it can be best used to provide a comprehensive evaluation of applicants to residency programs in radiation oncology. We initially discuss the current state of diversity in the field of radiation oncology and highlight the components of the residency selection process that may serve to perpetuate existing biases. Subsequently, the Accreditation Council for Graduate Medical Education and Association of American Medical Colleges holistic review framework is reviewed in detail to demonstrate the balanced assessment of potential applicants. The implementation of holistic review in medical school and residency selection to date is examined to underscore the potential value of holistic review in the radiation oncology residency selection process. Finally, recommendations for the practical implementation of holistic review in radiation oncology trainee selection are outlined. [ABSTRACT FROM AUTHOR]

Peer review (PR) is a critical component of radiation oncology practice, but the methods by which this is carried out are highly variable. There has been a substantial change in the format and structure of inter- and intra-disciplinary meetings with the recent rise in virtual/hybrid teleconferencing. We surveyed NCI National Community Oncology Research Program (NCORP) sites to better understand the format, structure, and content of radiation oncology PR. A one-time survey was distributed to ROs across 42 NCORP community sites through the Wake Forest NCORP Research Base (UG1CA189824) between January and February 2024. The survey explored the routine PR practices of radiation oncologists. Twenty-eight radiation oncologists from 13 NCORP sites, all indicated that they participate in routine PR. Years of practice were 0-5 in 25%, 6-10 years in 36%, and >10 years in 39%. The frequency of PR meetings was weekly in 22 of 26, daily in 2, and every other week in 2. The participants were limited to radiation oncologists at all responding practices; no practices included interdisciplinary collaboration with radiologists in their PR. The format of PR was a hybrid of in-person/virtual at 13 practices, virtual only (no in-person/hybrid option) at 10, in-person only (no virtual/hybrid option) at 4, with 1 not reported. Six practices reported using some form of asynchronous PR (PR performed independently without the treating physician). The timing of PR was reported by 27 and included after treatment planning is complete (n = 19), after contouring but before plan creation/dose calculation (n = 2), and a mix of both (n = 6). For those reporting a mix of PR timing, the median percent of cases that underwent PR before dose calculation was 15% (range = 5-60) with the remaining 85% (range = 40-95) reviewed after plan completion. Components of the plans subject to PR (reported as the number reviewing each component, out of the 28 respondents) included contours (23), targets/organs at risk (25), dose distributions (26), dose-volume histograms (26), prescription dose/fractionation (27), diagnostic imaging (12), pathology data (13), and treatment intent (23). Other components reviewed included informed consent (1) and morbidity and mortality conference (1). Peer review in radiation oncology is a universal practice with more heterogeneity in the meeting format than is in the content reviewed. Most practices are performing PR after treatment planning is complete. Additional focus on the timing and format of radiotherapy plan PR is necessary to develop best practices to optimize safety and ensure comprehensive PR. [ABSTRACT FROM AUTHOR]

Ovarian transposition (OT) was first proposed in the 1950s in order to avoid the hormonal and reproductive consequences of pelvic radiation therapy (RT). OT more than 1.5 cm superior to the iliac crest and radiation exposure limited between 120-315 cGy has been associated with preserved function. However, the dose at which immediate ovarian dysfunction is induced in 97.5% of patients decreases with increasing age and a recent meta-analysis discovered the rate of ovarian dysfunction could be as high as 33.1% in patients receiving OT in preparation for lower GI RT. No study has evaluated radiation doses that are typically seen in pelvic anatomic locations in patients being treated for lower GI cancers. Our study measured the distance from isodose lines to the sacral promontory (SP) in patients being treated for lower GI malignancies in order to determine a safe distance for OT. The radiation plans of female patients with lower GI malignancies from one academic institution were reviewed. Isodose lines of 200, 300, 600, 1200, and 1400 cGy were labeled. The distance from the isodose line to the SP was measured to the nearest 100th of a centimeter and the spinal level to which the isodose line corresponded was recorded. Measures of central tendency were calculated. 43 plans were analyzed. The average distance from the SP to the 200 cGy isodose line was 6.28 cm. This corresponded to the superior (n = 13) and middle (n = 14) aspects of L4. The 300 cGy isodose on average fell 5.40 cm from the SP while 600 cGy averaged around 3.76 cm away. 300 cGy corresponded with inferior L4 (n = 18) and L4/L5 (n = 11) or superior L5 (n = 12) for 600 cGy. 1200 and 1400 cGy averaged closest to the SP at only 2.86 and 2.72 cm away respectively, both falling around mid-L5 (n = 14). Based on our data, most OT procedures would need to place the ovaries more than 5-6 cm superior to the SP in order to minimize ovarian dysfunction in female patients undergoing RT for lower GI cancers. In comparison, the average ovary lies around 0.8 cm from the SP. Given that the average female L4 vertebral structure is 2.9 cm in length, this could indicate that the current standard of placing the ovaries at least 1.5 cm from the iliac crest underestimates the minimum safe distance for OT. As the general age of those with GI cancers decreases and the incidence increases, OT could become even more important in order to decrease the incidence of ovarian dysfunction in our female patients. [ABSTRACT FROM AUTHOR]

Multi-contrast MRI plays a vital role in accurate target delineation and treatment response evaluation during radiotherapy. This work aims to optimize multi-contrast MRI by integrating features across different contrasts and utilizing an easily obtained modality to guide high-quality reconstruction of target modalities from noisy and sparse samples. We propose a novel multi-contrast MRI reconstruction framework, which cascades a k-space learning network and an image space aggregation network to exploit features in both sensor and image domains. To deal with the imbalanced magnitudes of different frequency components in k-space, we propose a Low-to-High Frequency Progressive (LHFP) learning strategy. The network first recovers the low-frequency component and then emphasizes the high-frequency learning by reducing the loss weight of the low-frequency component. The low-high frequency boundary is adaptively estimated by a mask predictor module, which is optimized together with the k-space learning network. The network-learned k-space data are reconstructed to images and fed into the image domain network for further enhancement. To capture global dependencies in the image domain, we propose a transformer-based Self-to-Peer Aggregation (SPA) method to integrate features from multi-contrast MRI and improve the joint reconstruction accuracy. We evaluate our method on a multi-contrast MRI dataset, which contains both T1-weighted (T1WI) and T2-weighted (T2WI) MRI of brain tumor patients. We conduct experiments on two settings: 1) T1WI-guided 4-fold acceleration of the T2WI MRI, with only the reconstruction accuracy of T2WI evaluated; 2) T1WI-guided 4-fold acceleration of the T2WI MRI with low-field noise, where both reconstruction accuracies of T1WI and T2WI are evaluated. Our method leads to a peak-signal-to-noise (PSNR) improvement of 9.69 dB, 16.94 dB, and 11.16 dB for the T2WI 4X acceleration, T1WI low-field denoising, and low-field T2WI 4X acceleration, respectively. Moreover, our method significantly outperforms existing multi-contrast MRI reconstruction methods (K-DCNN, MINet, MTrans, MCCA). Through dual domain learning of k-space and image features, high-quality multi-contrast MRI can be obtained from noisy and sparse samples to support radiation treatment planning and follow-up. By exploiting global feature dependencies across different contrasts, improved robustness to noise and under-sampling artifacts can be achieved. [ABSTRACT FROM AUTHOR]

Purpose: Using microdosimetry, we investigated the relative biological effectiveness (RBE) and quality factor (Q¯) variations in- and out-of-field as a function of radiation quality for clinical protons.Methods and Materials: we irradiated a water phantom with a Spread-Out-Bragg-Peak (SOBP) and acquired microdosimetric spectra at several distal and lateral depths with a Tissue Equivalent Proportional Counter. The measurements were used as inputs to the Microdosimetric Kinetic and Loncol models to determine the RBE spatial distribution and compared it to predictions from the LETd-based McNamara model. Q¯ values, as well as biological and dose equivalent values were also calculated.Results: The data demonstrate that radiation quality changes more rapidly with depth than lateral distance from the SOBP. In-beam, yD ranges from ≈4 keV/μm at the entrance to 8 keV/μm at the SOBP far-end, reaching approximately 15 keV/μm at the penumbra. Out-of-field, the overall highest value of 23±2 keV/μm is observed at the beam-edge penumbra. Radiation quality changes cause RBE deviations from the clinical value of 1.1, whose extent depends on the approach used for assessing radiation quality as well as on the radiobiological model. For RBE10, microdosimetry-based models appear to reproduce better the radiobiological data than the LETd-model. Out-of-field, both the RBE and Q¯ values appear to have limitations in describing the radiation biological effectiveness. We also present a first comprehensive benchmark of TOPAS code against in- and out-of-field microdosimetric spectra of therapeutic protons.Conclusions: Further investigation will be necessary to evaluate the quantitative impact of RBE variations on the treatment planning and assess the clinical consequences both in terms of tumor control and normal tissue toxicity. The achievement of this goal calls for accurate radiobiological data to validate the RBE models. [ABSTRACT FROM AUTHOR]

131I-metaiodobenzylguanidine (131I-MIBG) has demonstrated efficacy as a single agent in neuroblastoma. Recent trials have focused on 131I-MIBG combination strategies, though little is known about the effect of putative radiosensitizers on biological markers of radiation exposure. NANT2011-01 evaluated 131I-MIBG therapy alone (arm A) or in combination with vincristine/irinotecan (arm B) or vorinostat (arm C) for patients with relapsed or refractory neuroblastoma. Blood samples were collected before and after 131I-MIBG infusion to determine levels of radiation-associated biomarkers (transcript and protein). The association of biomarker with treatment arm, clinical response, and treatment toxicity was analyzed. The cohort included 99 patients who had at least 1 biomarker available for analysis. Significant modulation in most biomarkers between baseline, 72, and 96 hours following 131I-MIBG was observed. Patients in arm C had the lowest degree of modulation in FLT3 ligand protein. Lower baseline BCL2 transcript levels were associated with higher overall response. Patients with greater increases in FLT3 ligand at 96 hours after 131I-MIBG therapy were significantly more likely to have grade 4 thrombocytopenia. Peripheral blood gene expression of the BCL2 family of apoptotic markers (BCL2L1 and BAX transcripts) was significantly associated with grade 4 hematologic toxicity. RNA sequencing demonstrated little overlap in the top modulated peripheral blood transcripts between randomized arms. Peripheral blood biomarkers relevant to radiation exposure demonstrate significant modulation after 131I-MIBG and concomitant radiation sensitizers affect extent of modulation. Biomarkers related to hematopoietic damage and apoptosis were associated with hematologic toxicity. [ABSTRACT FROM AUTHOR]

Background: We aimed to assess the value of dose distribution-based dosiomics and planning CT-based radiomics to predict radiation-induced temporal lobe injury (TLI) and guide individualized intensity-modulated radiotherapy.Materials and Methods: A total of 5599 nasopharyngeal carcinoma patients were enrolled, including 2503, 1072, 988, and 1036 patients in the training, validation, prospective test, and external test cohorts, respectively. The concordance index (C-index) was used to compare the performance of the radiomics and dosiomics models with that of the QUANTEC and Wen's models. The predicted TLI-free survival rates of redesigned simulated plans with the same dose-volume histogram but different dose distributions for same patient in a cohort of 30 randomly selected patients were compared by the Wilcoxon matched-pairs signed-rank test.Results: The radiomics and dosiomics signatures were constructed based on 30 selected CT features and 10 selected dose distribution features, respectively, which were important predictors of TLI-free survival (all P<0.001). However, the radiomics signature had a low C-index. The dosiomics risk model combining the dosiomics signature, D1cc, and age had favorable performance, with C-index values of 0.776, 0.811, 0.805, and 0.794 in the training, validation, prospective test, and external test cohorts, respectively, which were better than those of the QUANTEC model and Wen's model (all P<0.001). The dosiomics risk model can further distinguish patients in a same risk category divided by other models (all P<0.05). Conversely, the other models were unable to separate populations classified by the dosiomics risk model (all P>0.05). Two simulated plans with the same dose-volume histogram but different dose distributions had different TLI-free survival rates predicted by dosiomics risk model (all P≤0.002).Conclusion: The dosiomics risk model was superior to traditional models in predicting the risk of TLI. This is a promising approach to precisely predict radiation-induced toxicities and guide individualized intensity-modulated radiotherapy. [ABSTRACT FROM AUTHOR]

Introduction: The delineation of target volumes and organs at risk is the main source of uncertainty in radiation therapy (RT)(1). Numerous inter-observer variability (IOV) studies have been conducted, often with unclear methodology and non-standardized reporting. We aimed to identify the parameters chosen in conducting delineation IOV studies and assessed their performances and limits.Materiel and Methods: We conducted a systematic literature review to highlight major points of heterogeneity and missing in IOV studies published between 2018 and 2021. For the main used metrics, we did in silico analyses to assess their limits in specific clinical situations.Results: All disease sites were represented in the 66 studies. Organs at risks (OAR) were studied independently of tumor site in 29% of reviewed IOV studies. In 65% of studies, statistical analyses were performed. No gold standard (GS, i.e. reference) was defined in 36% of studies. A single expert was considered as GS in 21% studies without testing intraobserver variability. All studies reported both absolute and relative indices, including the Dice Similarity Coefficient (DSC) in 68% and Hausdorff Distance (HD) in 42%. Limitations were shown in silico for small structures when using DSC and dependence on irregular shapes when using HD. Variations in DSC values were large between studies and their thresholds inconsistent. Most (51%) studies included 1-10 cases. The median number of observers/experts was 7 (range 2-35). The intra-class correlation coefficient (ICC) was reported in 9% of cases only. Investigating feasibility of studying IOV in delineation, a minimum of 8 observers with 3 cases, or 11 observers with 2 cases, was required to demonstrate moderate reproducibility.Conclusion: Implementation of future IOV studies would benefit from a more standardized methodology: clear definitions of the gold standard, the metrics and a justification of the tradeoffs made in the choice of the number of observers and number of delineated cases should be provided. [ABSTRACT FROM AUTHOR]

Purpose: We provide 5-year results of prospectively collected radiation oncology (RO) job opportunities and a longitudinal assessment of RO graduate numbers within the United States.Methods and Materials: Full-time domestic RO job opportunities were collected and categorized using the American Society for Radiation Oncology (ASTRO) Career Center from July 1, 2016 to June 30, 2021. A chi-square test was used to compare regional job availability by city size and position type. The corresponding number of graduating United States (US) RO residents (2017-2021) was collected. US census and Medicare database resources were used as comparators for population and workforce estimates. Pearson's correlation coefficients were used to examine changes in data over time and a 2-tailed t test was used to assess for statistical significance.Results: Over the 5-year study period, 819 unique job offers were posted, compared with 935 RO graduates (0.88 total jobs-to-graduates ratio). Most jobs were nonacademic (57.6%), located in populated areas >1 million (57.1%; median: 1.57M), with the largest proportion of jobs seen in the South region (32.4%). One-third of academic jobs were located at satellites. Regional differences were seen between academic versus nonacademic job availability (P < .01), with the highest proportion of academic jobs seen in the Northeast (60.3%) and the lowest in the Midwest (34.5%). Differences between regions were also observed for jobs in areas >1 million versus ≤1 million (P < .01), with the most jobs in areas >1 million seen in the West (64.6%) and the least in the South (51.3%). Regional job availability over time did not differ by position type (academic vs nonacademic) or population area size (P = .11 and P = .27, respectively). Annual graduate numbers increased with time (P = .02), with the highest percentage of graduates trained in the South (30.8%). Regional distribution of jobs versus graduates significantly differed (P < .01) with the lowest jobs-to-graduates ratio observed in the Northeast (0.67) and highest ratio in the West (1.07). Regional RO workforce estimates based on the 4336 radiation oncologists who were Medicare providers in 2020 were compared with total jobs and graduates by region with no difference observed between the distributions of the workforce and jobs (P = .39), but comparisons between the workforce and graduates were proportionally different (P < .01). The number of total jobs (vs graduates) per 10 million population in the Northeast, South, Midwest, and West were 30.2 (45.1), 21.0 (22.7), 30.6 (33.4), and 22.6 (21.2), respectively.Conclusions: This multiyear quantitative assessment of the RO job market and graduates identified fewer job opportunities than graduates overall in most regions, most notably in the Northeast. Regional differences were seen between available job type (academic vs nonacademic) and population size (>1 million vs ≤1 million). The findings are worrisome for trainee oversupply and geographic maldistribution. The number and distribution of RO trainees and residency programs across the US should be evaluated to minimize job market imbalance for future graduates, promote workforce stability, and continue to meet the future societal needs of patients with cancer. [ABSTRACT FROM AUTHOR]

The Association of Residents in Radiation Oncology (ARRO) presents the Educator of the Year Award to outstanding faculty members at each participating institution every year. The aim of this study was to characterize the recipients of this award. The recipients of the annual ARRO Educator of the Year Award were identified from the years 2008 to 2019. Publicly available website domains were accessed to obtain data regarding clinical treatment site, number of sites treated, whether they were at the same institution where they trained, academic rank, sex, American Society for Radiation Oncology fellow status, repeat awardee status during the period, and number of years since board certification. H- and m-indices were obtained from Scopus and calculated based on the time of the award. General workforce data were obtained from American Society for Radiation Oncology and recently published articles. The authors performed correlative analyses stratified by sex and logistic regression to determine predictors of repeat awardee status. There were a total of 607 ARRO educator awards from the years 2008 to 2019. The majority of recipients were male (77.6%) and assistant professors (39.0%). The median number of years from board certification was 7 (interquartile range, 3-17) and the median h- and m-indices were 14 and 1, respectively. When stratified by sex, publication metrics were significantly higher for men (P <.05), and men were more likely to be repeat awardees (P <.001) and have higher academic rank (P =.007). On multivariate analysis, those of higher rank were more likely to be repeat awardees (associate odds ratio [OR], 3.55; P <.001; full professor OR, 2.04; P =.046) and less likely to be women (OR, 0.41; P =.002), and h- and m-indices were not associated with repeat awardee status. Recipients of the ARRO educator award appear to be diverse in rank and experience; however, associate professor rank and sex were associated with continued recognition of educational excellence. [ABSTRACT FROM AUTHOR]

The aim of this TROG 12.01 substudy was to report longitudinal variations in patient- (PRO) and clinician-reported outcomes based on receipt of unilateral (URT) or bilateral radiation therapy (BRT). Patients with lateralized T1-2 N1-2b human papillomavirus-associated tonsillar carcinoma (AJCC7) enrolled on TROG 12.01 were eligible. The primary endpoint was patient-reported radiation symptom severity score (MDASI-RSS) at 2 years, a composite of 9 MDASI-Head and Neck (HN) symptom items. Secondary endpoints included patient-reported symptom burden and interference (MDASI-HN), quality of life (FACT-HN), emotional distress (HADS), return to work (RTW), clinician-reported performance status scale (PSS-HN), and late adverse events (CTCAE). Mean MDASI-RSS, symptom severity (MDASI-SS), symptom interference (MDASI-SI) and selected single items were compared 1 week, 3 months, and 2 years post-RT. Seventy-four patients were eligible for analysis (26 URT, 48 BRT). Median follow-up was 3.7 years (1.8-5.2 years). Sociodemographic, staging, and treatment variables were mostly balanced, with larger primaries observed in the BRT group. Four regional failures were reported (3 URT, 1 BRT), including one isolated contralateral regional failure in the URT cohort. Mean MDASI-RSS scores did not differ at 2 years (URT vs BRT, 1.1 vs 1.3; difference 0.1 [95% CI: –0.7 to 0.9], P =.75) or at any other time points for the MDASI-RSS, MDASI-SS, and MDASI-SI scores, except for worse MDASI-SI 1 week after treatment in the BRT group (4.7 vs 5.6). Fatigue (6.6 vs 5.4) at 1 week and dry mouth (3.5 vs 2.0) at 2 years were also worse in the BRT group. FACT-HN, HADS, RTW, PSS-HN, and CTCAE results were similar across the follow-up period. In this favorable-risk cohort, treatment laterality resulted in fewer differences than anticipated in patient-reported or clinician-reported outcomes. Two years after treatment patients treated with BRT reported significantly worse dry mouth. Longer follow-up is needed to determine the impact of treatment laterality on late effects. [ABSTRACT FROM AUTHOR]

Background: During the COVID-19 pandemic, many radiation oncology departments worldwide adopted the use of shorter and more intense hypofractionated regimens. Hospital foot traffic was reduced through virtual care. This study's primary objective was to assess the collective environmental impact of these strategic changes by identifying sources of carbon dioxide equivalents (CO2e). The rate of radiation-related adverse event from the increased use of hypofractionated treatments was assessed.Methods: All patients treated with external beam radiation therapy from April 1, 2019 to March 31, 2021 at our single institution were identified (n=10,175) along with their radiotherapy visits (176,423 fractions), and unplanned visits to the radiation nursing clinic (RNC) or emergency (ER) department. Out-patient hospital and virtual visits (n=75,853) during this same period were also analyzed. Environmental impact measures, including linear accelerator power usage, patient travel distances, and personal protection equipment (PPE) consumption were all converted into CO2e.Results: The use of curative hypofractionated regimens increased from 17% to 27% during the pandemic year. Carbon footprint was reduced by 39% during the pandemic year (1,332,388 kg CO2e) as compared to the pre-pandemic year (2,024,823 kg CO2e). Comparing patients in the pre-pandemic vs. pandemic year, there was a significant reduction in the proportion of hypofractionated patients who needed a visit to either the RNC (39% vs. 25%; p<0.001) or ER (6% vs. 2%; p<0.001) during and within 90 days of radiotherapy.Discussion: This is the first study to demonstrate the environmental benefits of increased use of hypofractionated regimens and virtual care, while assuring that there was no added acute radiation-related adverse event. Our findings support their continued use as one of many long-term strategies to reduce the environmental footprint of healthcare delivery. [ABSTRACT FROM AUTHOR]

Radiation oncology trainees may benefit from more standardized competency-based assessment in practical skills such as contouring which are presently only assessed observationally by attendings. This is especially true in the world of gynecologic brachytherapy, given trends of declining brachytherapy utilization, lower competence reported by graduating residents, and low institutional brachytherapy volumes. We hope to develop a standardized method to objectively grade and assess contours created by radiation oncology residents for competency-based assessment in gynecologic brachytherapy. A magnetic resonance and computed tomography-based cervical cancer brachytherapy contouring simulation will be designed using an interactive online platform, and radiation oncology residents will be asked to contour the gross tumor volume (GTV) and high-risk clinical target volume (HRCTV) as they would for radiation planning. These contours will be evaluated by a gynecologic brachytherapy expert using three-tier system utilized in clinical trials. In addition, three experimental methods will be investigated to determine their suitability as a surrogate for expert evaluation. These include (1) non-expert ("novice") review of contours based on a generated rubric, (2) digital evaluation using dice similarity coefficient, and (3) artificial intelligence software designed to emulate scoring provided by an expert in the field. This study is a work in progress, and we have applied for grant funding through the American Board of Medical Specialties Research and Education Foundation grant. We expect that one or more of the three experimental modalities will result in contour evaluations that do not differ significantly from an evaluation of an expert in the field. This study will also offer insight into the feasibility and practicality of contour evaluation using physician novice, digital metric, and artificial-intelligence-based feedback. If demonstrated to be feasible, practical, and comparable in nature to feedback given by an expert in the field, similar programs may be designed for other sites, both for brachytherapy and external beam radiotherapy. Ultimately, one or more of these experimental evaluation modalities may be considered for use in competency-based evaluation of residents, as they would be much more easily generalizable across residency programs compared to expert contour review. Future directions include implementation of such assessment modalities into formal resident evaluation and utilization of digital and artificial intelligence-based software for assessment of other practical skills including plan evaluation and approval of treatment set-up. [ABSTRACT FROM AUTHOR]

Development of radiation treatment plans requires an understanding of normal anatomy, the pathologic appearance of cancer, and patterns of cancer spread on medical imaging. To address this need, a multi-institutional Oncoanatomy course was developed with radiation oncology residents participating in anatomic-site based educational modules, followed by analysis of cadaveric pro-sections prepared by trained anatomists. However, given the routine incorporation of a growing number of imaging modalities in radiation treatment planning, we assessed the current structure of our Oncoanatomy class and the possible need for curricular modification with a focus on radiation oncology resident knowledge of oncologic imaging. A survey was designed to assess the confidence in interpreting different image types (CT, MRI, nuclear medicine scans, breast imaging), need for radiology teaching by disease site, utility of different educational methods, and suggestions for the new course. The survey was distributed to residents and recent graduates of two radiation oncology residency programs. Respondents were asked about prior formal radiology training and to rate their confidence in interpreting different imaging studies on a 1-5 scale (1= don't know at all, 5=know extremely well). Overall, there were 13 respondents; 23.1% were PGY-2 residents, 30.8% were PGY-3 residents, 30.8% were PGY-4 residents, and 15.4% were attendings. Of all respondents, 61.5% had a formal radiology rotation in medical school, and 15.4% had a formal radiology rotation in their intern year. Respondents were most confident in their ability to interpret genitourinary CT imaging (mean=3.5, range 1-5) and least confident in interpreting pediatric CT imaging (mean=2, range 1-3). Respondents were most confident in interpreting central nervous system MR imaging (mean=3.4, range 1-5) and least confident in interpreting head and neck MR imaging (mean=2.2, range 1-4). When asked how they learned to interpret imaging, 11 (84.6%) respondents selected "discussions with an attending while performing radiation treatment planning", 10 (76.9%) selected "speaking with radiologists directly", and 10 (76.9%) selected "during imaging review as part of consult preparation and correlating to written report". Suggestions for the new course included CT based anatomy teaching, lectures from radiologists, and interactive contouring sessions. A needs assessment was performed for an imaging-based course focusing on radiographic anatomy. Overall, there was support for increased teaching by radiologists and review of imaging-based anatomy in a new onco-radiology course. [ABSTRACT FROM AUTHOR]