Radiation Oncology Study Research Articles

Autologous Peripheral Blood Stem Cell Transplantation and Timing of Local Radiation Therapy in Patients With Malignant Lymphoma: Results of the Japanese Radiation Oncology Study Group Questionnaire Survey.

Malignant lymphoma (ML) including Hodgkin's lymphoma and non-Hodgkin's lymphoma is often treated with local radiation therapy (RT) in combination with autologous hematopoietic stem cell transplantation (ASCT) to prevent relapse; however, the efficacy and optimal timing of this approach is unclear. In this study, a national survey conducted by the Japanese Radiation Oncology Study Group reviewed ML cases from 2011 to 2019 to determine whether RT should be added to ASCT, focusing on the use of autologous peripheral blood stem cell transplantation (auto-PBSCT), a predominant form of ASCT. The survey encompassed 92 patients from 11 institutes, and assessed histological ML types, treatment regimens, timing of RT relative to auto-PBSCT, and associated adverse events. The results indicated no significant differences in adverse events, including myelosuppression, based on the timing of RT in relation to auto-PBSCT. However, anemia was more prevalent when RT was administered before auto-PBSCT, and there was a higher incidence of neutropenia recovery delay in patients receiving RT after auto-PBSCT. This study provides valuable insights into the variable practices of auto-PBSCT and local RT in ML treatment, emphasizing the need for optimized timing of these therapies to improve patient outcomes and reduce complications.

Radiotherapy Results in Locally Advanced Sinonasal Cancer: Turkish Society for Radiation Oncology, Head and Neck Study Group 01-005.

This study aims to examine the treatment outcomes and related factors in locally advanced sinonasal cancer across Turkiye. Twelve centers participants of the Turkish Society for Radiation Oncology Head and Neck Study Group attended the study. One hundred and ninety-four patients treated with intensity-modulated radiation therapy between 2001 and 2021 were analyzed retrospectively. The survival analysis was performed using the Kaplan-Meier method. Acute and late toxicity were recorded per Common Toxicity Criteria for Adverse Events V4.0. The median age was 58 years and 70% were male. The majority of tumors were located in maxillary sinus (59%). Most of the patients (%83) had T3 and T4A disease. Fifty-three percent of patients were in stage 4A. Radiotherapy was administered to 80% of the patients in the adjuvant settings. Median 66Gy dose was administered in median 31 fractions. Chemotherapy was administered concomitantly with radiotherapy in 45% of the patients mostly with weekly cisplatin. No grade ≥4 acute and late toxicity was observed. The median follow-up was 43 months. The 5-year and 10-year overall survival (OS); locoregional recurrence-free survival (LRFS); distant metastasis-free survival (DMFS), and progression-free survival (PFS) rates were 61% and 47%; 69% and 61%; 72%, and 69%, and 56% and 49%, respectively. In the multivariate analysis, several factors demonstrated significant influence on OS, such as performance status, surgery, and lymph node involvement. Moreover, surgery was the key prognostic factor for LRFS. For DMFS, lymph node involvement and surgical margin were found to be influential factors. In addition, performance status and lymph node involvement were identified as significantly affecting PFS. In our study, the authors obtained promising results with IMRT. Performance status, lymph node involvement, and surgery emerged as the primary factors significantly influencing OS.

Current Strengths and Weaknesses of ChatGPT as a Resource for Radiation Oncology Patients and Providers

Purpose: ChatGPT, an artificial intelligence (AI) program that uses natural language processing to generate conversational-style responses to questions or inputs, is increasingly being used by both patients and healthcare professionals. This study aims to evaluate the accuracy and comprehensiveness of ChatGPT in radiation oncology-related domains, including answering common patient questions, summarizing landmark clinical research studies, and providing literature reviews with specific references supporting current standard of care clinical practice in radiation oncology. Methods: We assessed the performance of ChatGPT version 3.5 (ChatGPT3.5) in three areas. We evaluated ChatGPT3.5’s ability to answer 28 templated patient-centered questions applied across 9 cancer types. We then tested ChatGPT3.5’s ability to summarize specific portions of 10 landmark studies in radiation oncology. Next, we used ChatGPT3.5 to identify scientific studies supporting current standard of care practice in clinical radiation oncology for five different cancer types. Each response was graded independently by two reviewers, with discordant grades resolved by a third reviewer. Results: ChatGPT3.5 frequently generated inaccurate or incomplete responses. Only 39.7% of responses to patient-centered questions were considered correct and comprehensive. When summarizing landmark studies in radiation oncology, 35.0% of ChatGPT3.5′s responses were accurate and comprehensive, improving to 43.3% when provided the full text of the study. ChatGPT3.5′s ability to present a list of studies related to standard of care clinical practices was also unsatisfactory, with 50.6% of the provided studies fabricated. Conclusion: ChatGPT should not be considered a reliable radiation oncology resource for patients or providers at this time, as it frequently generates inaccurate or incomplete responses. However, natural language programming-based AI programs are rapidly evolving, and future versions of ChatGPT or similar programs may demonstrate improved performance in this domain.

The Environmental Impact of Radiation Oncology: The "Footprint" of External Beam Radiation Therapy

There is a growing concern for the healthcare sector's impact on the environment. Prior carbon impact studies in radiation oncology have been limited in scope and methodology. This study aims to fill this gap by using an internationally recognized cradle-to-grave life cycle assessment (LCA) approach to quantify all environmental impacts from raw material extraction to product disposal for external beam radiation therapy (EBRT) in treating the most commonly diagnosed cancers. This LCA was performed in accordance with ISO 14040 and 14044 at a single academic medical center. It quantified the environmental impact of EBRT across four categories: global warming potential (GWP), carcinogenic and non-carcinogenic human toxicity, and respiratory effects (PM2.5), from initial consultation to the completion of the last EBRT fraction for each disease site. Data collection involved weighing all materials used, measuring/calculating building and equipment electricity usage (e.g., HVAC and Linacs), and recording patient and staff transit. The study analyzed the impact of both minimum and maximum fractionations for each disease site and simulated alternative clinical scenarios such as telemedicine, renewable energy use and hypofractionation. Regardless of disease site, there were significant differences in the environmental impacts associated with transit, electricity and supplies for EBRT treatment cycles. Staff and patient transport contributed the most, accounting for >92% of the total environmental impact including GWP (5.02x102 ± 9.38x101 kgCO2eq), carcinogenic (6.25x10-5 ± 1.23x10-5 CTUh) and non-carcinogenic human toxicity (1.16x10-4 ± 2.35x10-5 CTUh). Electricity accounted for 1-13% of the total impact, with most impact arising from respiratory effects (3.05x10-2 kg ± 2.72x10-3 PM2.5). The impact of supplies and materials was less than 3% across all categories. Alternative scenario modeling showed that telemedicine had a maximum impact reduction of 3.5% (2.54x 101kgCO2eq) for GWP, while renewable energy use had a maximum impact reduction of 8% (2.37 x 10-2 PM2.5) for respiratory effects. Reducing the number of total treatment days via hypofractionation can reduce GWP by 67-78% and carcinogenic emissions by 63-77% (3.48 x 102 - 5.53 x 102 kgCO2eq) and (3.73 x 10-5 - 6.85 x 10-5CTUh), respectively, with variation depending on the total number of fractions. This study provides a comprehensive environmental impact assessment for EBRT among the most commonly treated disease sites, establishing a baseline metric and identifying targets for impact reduction. We are currently performing a multi-center validation study to be completed by June 2023. Our findings fill an important gap in cancer care and are critical for developing sustainable practices in the face of increasing demand for radiotherapy in a changing climate. LCAs evaluating all aspects of cancer care will be essential for promoting equitable and sustainable care.

Analysis of Radiation Therapy Quality Assurance in NRG Oncology RTOG 0848

NRG/Radiation Therapy Oncology Group 0848 is a 2-step randomized trial to evaluate the benefit of the addition of concurrent fluoropyrimidine and radiation therapy (RT) after adjuvant chemotherapy (second step) for patients with resected pancreatic head adenocarcinoma. Real-time quality assurance (QA) was performed on each patient who underwent RT. This analysis aims to evaluate adherence to protocol-specified contouring and treatment planning and to report the types and frequencies of deviations requiring revisions. In addition to a web-based contouring atlas, the protocol outlined step-by-step instructions for generating the clinical treatment volume through the creation of specific regions of interest. The planning target volume was a uniform 0.5 cm clinical treatment volume expansion. One of 2 radiation oncology study chairs independently reviewed each plan. Plans with unacceptable deviations were returned for revision and resubmitted until approved. Treatment started after final approval of the RT plan. From 2014 to 2018, 354 patients were enrolled in the second randomization. Of these, 160 patients received RT and were included in the QA analysis. Resubmissions were more common for patients planned with 3-dimensional conformal RT (43%) than with intensity modulated RT (31%). In total, at least 1 resubmission of the treatment plan was required for 33% of patients. Among patients requiring resubmission, most only needed 1 resubmission (87%). The most common reasons for resubmission were unacceptable deviations with respect to the preoperative gross target volume (60.7%) and the pancreaticojejunostomy (47.5%). One-third of patients required resubmission to meet protocol compliance criteria, demonstrating the continued need for expending resources on real-time, pretreatment QA in trials evaluating the use of RT, particularly for pancreas cancer. Rigorous QA is critically important for clinical trials involving RT to ensure that the true effect of RT is assessed. Moreover, RT QA serves as an educational process through providing feedback from specialists to practicing radiation oncologists on best practices.

Carbon-ion radiotherapy for oligometastatic liver disease: A national multicentric study by the Japan Carbon-Ion Radiation Oncology Study Group (J-CROS).

Reports on the therapeutic efficacy and safety of carbon-ion radiotherapy (C-ion RT) for oligometastatic liver disease are limited, with insufficient evidence. This study aimed to evaluate the clinical outcomes of C-ion RT for oligometastatic liver disease at all Japanese facilities using the nationwide cohort data. We reviewed the medical records to obtain the nationwide cohort registry data on C-ion RT between May 2016 and June 2020. Patients (1) with oligometastatic liver disease as confirmed by histological or diagnostic imaging, (2) with ≤3 synchronous liver metastases at the time of treatment, (3) without active extrahepatic disease, and (4) who received C-ion RT for all metastatic regions with curative intent were included in this study. C-ion RT was performed with 58.0-76.0 Gy (relative biological effectiveness [RBE]) in 1-20 fractions. In total, 102 patients (121 tumors) were enrolled in this study. The median follow-up duration for all patients was 19.0 months. The median tumor size was 27 mm. The 1-year/2-year overall survival, local control, and progression-free survival rates were 85.1%/72.8%, 90.5%/78.0%, and 48.3%/27.1%, respectively. No patient developed grade 3 or higher acute or late toxicity. C-ion RT is a safe and effective treatment for oligometastatic liver disease and may be beneficial as a local treatment option in multidisciplinary treatment.

Temporal Profiles of Symptom Scores after Palliative Radiotherapy for Bleeding Gastric Cancer with the Adjustment for the Palliative Prognostic Index: An Exploratory Analysis of a Multicenter Prospective Observational Study (JROSG 17-3)

<h3>Purpose/Objective(s)</h3> Although palliative radiotherapy for gastric cancer may improve some symptoms, it may also have negative impact due to its toxicity. We investigated whether symptoms improved after radiotherapy with adjustment for the Palliative Prognostic Index (PPI) considering that patients with limited survival tend to experience deterioration of symptoms. <h3>Materials/Methods</h3> This study was an exploratory analysis of a multicenter prospective observational trial (Japanese Radiation Oncology Study Group [JROSG] 17-3). We assessed six symptom scores (nausea, lack of appetite, fatigue, shortness of breath, pain at the irradiated area, and distress) based on the M. D. Anderson Symptom Inventory at registration and 2, 4, and 8 weeks thereafter. PPI prediction model contains five independent indicators: palliative performance scale, intake, edema, dyspnea at rest, and delirium. A higher PPI score means worse survival. We tested whether symptoms linearly improved after adjusting for the baseline PPI. Shared parameter models were used to account for potential bias in missing data. <h3>Results</h3> The present study analyzed all 55 patients enrolled in JROSG 17-3. The median age was 73 years (range, 50–93 years). The average PPI was 2.9 (95% confidence interval: 2.2–3.6). The median 20 Gy (range, 8–45 Gy) total radiation dose was delivered in a median of 5 fractions. At registration, 27 (49%), 36 (65%), 44 (80%), 38 (69%), 29 (53%) and 44 patients (80%) had nausea, lack of appetite, fatigue, shortness of breath, pain, and distress, respectively. All six symptoms were evaluable for 48 (87%), 36 (65%), and 28 (51%) patients at 2, 4, and 8 weeks, respectively. With time from registration as the only explanatory variable in the model, a significant linear decrease was observed in shortness of breath, pain, and distress (slopes, −0.26, −0.22, and −0.19, respectively). Given that the interaction terms (i.e., PPI × time) were not significantly associated with symptom scores in any of the six symptoms, only PPI was included as the main effect in the final multivariable models. After adjusting for the PPI, shortness of breath, pain, and distress significantly improved (slope, −0.25, −0.19, and −0.17; p < 0.001, 0.002, and 0.047, respectively). Higher PPI scores were associated with higher symptom scores in all six symptoms. <h3>Conclusion</h3> Shortness of breath, pain, and distress significantly improved after radiotherapy. Moreover, a higher PPI was significantly associated with higher symptom scores at all time points, including baseline. In contrast, PPI did not seem to influence the improvement of these symptoms. Regardless of the expected survival, patients receiving radiotherapy for gastric cancer can expect improvement in shortness of breath, pain, and distress over 8 weeks.

Infrastructure platform for privacy-preserving distributed machine learning development of computer-assisted theragnostics in cancer

IntroductionEmerging evidence suggests that data-driven support tools have found their way into clinical decision-making in a number of areas, including cancer care. Improving them and widening their scope of availability in various differing clinical scenarios, including for prognostic models derived from retrospective data, requires co-ordinated data sharing between clinical centres, secondary analyses of large multi-institutional clinical trial data, or distributed (federated) learning infrastructures. A systematic approach to utilizing routinely collected data across cancer care clinics remains a significant challenge due to privacy, administrative and political barriers. MethodsAn information technology infrastructure and web service software was developed and implemented which uses machine learning to construct clinical decision support systems in a privacy-preserving manner across datasets geographically distributed in different hospitals. The infrastructure was deployed in a network of Australian hospitals. A harmonized, international ontology-linked, set of lung cancer databases were built with the routine clinical and imaging data at each centre. The infrastructure was demonstrated with the development of logistic regression models to predict major cardiovascular events following radiation therapy. ResultsThe infrastructure implemented forms the basis of the Australian computer-assisted theragnostics (AusCAT) network for radiation oncology data extraction, reporting and distributed learning. Four radiation oncology departments (across seven hospitals) in New South Wales (NSW) participated in this demonstration study. Infrastructure was deployed at each centre and used to develop a model predicting for cardiovascular admission within a year of receiving curative radiotherapy for non-small cell lung cancer. A total of 10,417 lung cancer patients were identified with 802 being eligible for the model. Twenty features were chosen for analysis from the clinical record and linked registries. After selection, 8 features were included and a logistic regression model achieved an area under the receiver operating characteristic (AUROC) curve of 0.70 and C-index of 0.65 on out-of-sample data. ConclusionThe infrastructure developed was demonstrated to be usable in practice between clinical centres to harmonize routinely collected oncology data and develop models with federated learning. It provides a promising approach to enable further research studies in radiation oncology using real world clinical data.

Carbon-ion radiotherapy for urological cancers.

Carbon-ions are charged particles with a high linear energy transfer, and therefore, they make a better dose distribution with greater biological effects on the tumors compared with photons and protons. Since prostate cancer, renal cell carcinoma, and retroperitoneal sarcomas such as liposarcoma and leiomyosarcoma are known to be radioresistant tumors, carbon-ion radiotherapy, which provides the advantageous radiobiological properties such as an increasing relative biological effectiveness toward the Bragg peak, a reduced oxygen enhancement ratio, and a reduced dependence on fractionation and cell-cycle stage, has been tested for these urological tumors at the National Institute for Radiological Sciences since 1994. To promote carbon-ion radiotherapy as a standard cancer therapy, the Japan Carbon-ion Radiation Oncology Study Group was established in 2015 to create a registry of all treated patients and conduct multi-institutional prospective studies in cooperation with all the Japanese institutes. Based on accumulating evidence of the efficacy and feasibility of carbon-ion therapy for prostate cancer and retroperitoneal sarcoma, it is now covered by the Japanese health insurance system. On the other hand, carbon-ion radiotherapy for renal cell cancer is not still covered by the insurance system, although the two previous studies showed the efficacy. In this review, we introduce the characteristics, clinical outcomes, and perspectives of carbon-ion radiotherapy and our efforts to disseminate the use of this new technology worldwide.

Temporal Profiles of Symptom Scores After Palliative Radiotherapy for Bleeding Gastric Cancer With Adjustment for the Palliative Prognostic Index: An Exploratory Analysis of a Multicentre Prospective Observational Study (JROSG 17–3)

AimsAlthough palliative radiotherapy for gastric cancer may improve some symptoms, it may also have a negative impact due to its toxicity. We investigated whether symptoms improved after radiotherapy with adjustment for the Palliative Prognostic Index (PPI) considering that patients with limited survival tend to experience deterioration of symptoms. Materials and methodsThis study was an exploratory analysis of the Japanese Radiation Oncology Study Group study (JROSG 17-3). We assessed six symptom scores (nausea, anorexia, fatigue, shortness of breath, pain at the irradiated area and distress) at registration and 2, 4 and 8 weeks thereafter. We tested whether symptoms linearly improved after adjusting for the baseline PPI. Shared parameter models were used to adjust for potential bias in missing data. ResultsThe present study analysed all 55 patients enrolled in JROSG 17-3. With time from registration as the only explanatory variable in the model, a significant linear decrease was observed in shortness of breath, pain and distress (slopes, −0.26, −0.22 and −0.19, respectively). Given that the interaction terms (i.e. PPI × time) were not significantly associated with symptom scores in any of the six symptoms, only PPI was included as the main effect in the final multivariable models. After adjusting for the PPI, shortness of breath, pain and distress significantly improved (slope, −0.25, −0.19 and −0.17; P < 0.001, 0.002 and 0.047, respectively). An improvement in fatigue and distress was observed only in patients treated with a biologically effective dose ≤14.4 Gy. ConclusionShortness of breath, pain and distress improved after radiotherapy. Moreover, a higher PPI was significantly associated with higher symptom scores at all time points, including baseline. In contrast, PPI did not seem to influence the improvement of these symptoms. Regardless of the expected survival, patients receiving radiotherapy for gastric cancer can expect an improvement in shortness of breath, pain and distress over 8 weeks. Multiple-fraction radiotherapy might hamper the improvement in fatigue and distress by its toxicity or treatment burden.

A portable magnet for radiation biology and dosimetry studies in magnetic fields.

In the current and rapidly evolving era of real-time MRI-guided radiotherapy, our radiation biology and dosimetry knowledge is being tested in a novel way. This paper presents the successful design and implementation of a portable device used to generate strong localized magnetic fields. These are ideally suited for small-scale experiments that mimic the magnetic field environment inside an MRI-linac system, or more broadly MRI-guided particle therapy aswell. A portable permanent magnet-based device employing an adjustable steel yoke and magnetic field focusing cones has been designed, constructed, and tested. The apparatus utilizes two banks of Nd Fe B permanent magnets totaling around 50 kg in mass to generate a strong magnetic field throughout a small volume between two pole tips. The yoke design allows adjustment of the pole tip gap and exchanging of the focusing cones. Further to this, beam portal holes are present in the yoke and focusing cones, allowing for radiation beams of up to 5 5 cm to pass through the region of high magnetic field between the focusing cone tips. Finite element magnetic modeling was performed to design and characterize the performance of the device. Automated physical measurements of the magnetic field components at various locations were measured to confirm the performance. The adjustable pole gap and interchangeable cones allows rapid changing of the experimental set-up to allow different styles of measurements to beperformed. A mostly uniform magnetic field of 1.2 T can be achieved over a volume of at least 3 3 3 cm . This can be reduced in strength to 0.3 T but increased in volume to 10 10 10 cm via removal of the cone tips and/or adjustment of the steel yoke. Although small, these volumes are sufficient to house radiation detectors, cell culture dishes, and various phantom arrangements targeted at examining small radiation field dosimetry inside magnetic field strengths that can be changed with ease. Most important is the ability to align the magnetic field both perpendicular to, or inline with, the radiation beam. To date, the system has been successfully used to conduct published research in the areas of radiation detector performance, lung phantom dosimetry, and how small clinical electron beams behave in these strong magneticfields. A portable, relatively inexpensive, and simple to operate device has successfully been constructed and used for performing radiation oncology studies around the theme of MRI-guided radiotherapy. This can be in either inline and perpendicular magnetic fields of up to 1.2 T with x-ray and particlebeams.

Prediction of out-of-field recurrence after chemoradiotherapy for cervical cancer using a combination model of clinical parameters and magnetic resonance imaging radiomics: a multi-institutional study of the Japanese Radiation Oncology Study Group.

We retrospectively assessed whether magnetic resonance imaging (MRI) radiomics combined with clinical parameters can improve the predictability of out-of-field recurrence (OFR) of cervical cancer after chemoradiotherapy. The data set was collected from 204 patients with stage IIB (FIGO: International Federation of Gynecology and Obstetrics 2008) cervical cancer who underwent chemoradiotherapy at 14 Japanese institutes. Of these, 180 patients were finally included for analysis. OFR-free survival was calculated using the Kaplan–Meier method, and the statistical significance of clinicopathological parameters for the OFR-free survival was evaluated using the log-rank test and Cox proportional-hazards model. Prediction of OFR from the analysis of diffusion-weighted images (DWI) and T2-weighted images of pretreatment MRI was done using the least absolute shrinkage and selection operator (LASSO) model for engineering image feature extraction. The accuracy of prediction was evaluated by 5-fold cross-validation of the receiver operating characteristic (ROC) analysis. Para-aortic lymph node metastasis (p = 0.003) was a significant prognostic factor in univariate and multivariate analyses. ROC analysis showed an area under the curve (AUC) of 0.709 in predicting OFR using the pretreatment status of para-aortic lymph node metastasis, 0.667 using the LASSO model for DWIs and 0.602 using T2 weighted images. The AUC improved to 0.734 upon combining the pretreatment status of para-aortic lymph node metastasis with that from the LASSO model for DWIs. Combining MRI radiomics with clinical parameters improved the accuracy of predicting OFR after chemoradiotherapy for locally advanced cervical cancer.

Trends in Radiation Oncology Treatment Fractionation at a Single Academic Center, 2014-2020

Recent landmark studies in radiation oncology suggest hypofractionation is appropriate for treatment of many cancers. The COVID-19 pandemic may have increased pressure to adopt hypofractionation because of concerns about disease spread at treatment centers. We know of no recent U.S. study of trends in radiation fractionation that includes comparisons of multiple disease sites and data post-COVID. Therefore, we sought to describe trends in treatment fractionation at a single academic center from 2014-2020.From our institutional database, for the years 2014-2020, we extracted the total number of patients treated, total number of fractions delivered, and mean number of fractions per treatment course for all cancers and specifically for treatment of breast cancer, prostate cancer, and bone metastases. For breast and prostate, we included only radiation courses delivered to the primary site.The dataset included 16,224 courses of radiation treatment and 257,352 treatment fractions. The mean number of fractions per treatment course overall declined steadily throughout the study period, from 18.3 in 2014 to 14.9 in 2020. For breast cancer, the mean number of fractions per treatment course was steady from 2014-2016 but began to decline more rapidly from 2017-2020. Fractionation for prostate cancer followed a similar time trend, but there was a more substantial decline from 2014 (mean 36.6 fractions per treatment course) to 2020 (mean 16.7 fractions per treatment course). For bone metastases, fractionation was relatively consistent throughout the study period. For breast patients, during the onset of COVID-19 in 2020, the monthly rate of decrease in number of fractions increased to 0.19 from a historical mean of 0.05, as the mean number of sessions dropped from 22 to 19. For bone metastases, in 2020, the mean number of sessions dropped from 6.3 to 5.3, with a monthly rate of decrease of 0.13 compared to historical mean of 0.03. COVID-19 did not spike the monthly rate of change in number of fractions for prostate which began a steady decline in 2017 with increased use of SBRT.We observed increased adoption of hypofractionation at our institution during the study period for both breast and prostate cancer. For bone metastases, hypofractionation had largely been adopted before the study period. There was evidence of an accelerated trend toward hypofractionation for some cancers during the COVID-19 pandemic.

Analysis of Radiation Therapy Quality Assurance in NRG Oncology RTOG 0848

<h3>Purpose/Objective(s)</h3> NRG/RTOG 0848 is a two-step randomized trial to evaluate the benefit of the addition of concurrent fluoropyrimidine and radiotherapy (RT) following adjuvant gemcitabine-based chemotherapy (2^nd step) for patients with resected pancreatic head adenocarcinoma. Real-time quality assurance (QA) was performed for each patient who underwent RT. QA findings were reviewed, frequencies & reasons for resubmissions are reported. <h3>Materials/Methods</h3> Patients were treated using either a 3D-conformal RT (3DCRT) or intensity-modulated RT (IMRT) technique. In addition to a web-based contouring atlas, the protocol outlined step-by-step instructions for generating the clinical treatment volume (CTV) through the creation of specific regions of interest. The planning target volume (PTV) was established by expanding the CTV by 0.5 cm in all directions. Treatment planning data, including pre-operative imaging, surgical and pathology reports, simulation images with isodose lines, structure set, and dose volume histograms were submitted for review. One of two radiation oncology study chairs independently reviewed each plan. Plans with unacceptable deviations were returned for revision and then resubmitted for review until approved. Treatment started after final approval of the RT plan. <h3>Results</h3> Of the 354 patients who underwent second randomization, 180 were randomized to the RT arm. Of these, 160 received RT and were included in the QA analysis. Most patients (86%) were treated using IMRT. Resubmissions were more common for patients planned with 3D-CRT (43%) than with IMRT (31%). In total, at least one resubmission of the treatment plan was required for 33% of patients (see Table 1). Among patients requiring resubmission, the majority only needed to be resubmitted once (87%). The most common reasons for resubmission were unacceptable deviations with respect to the pre-operative gross target volume (GTV, 61%) and the pancreatojejunostomy (48%), leading to unacceptable deviations of the contours of the CTV and PTV (70% for each). Most patients requiring a resubmission had 5-9 unacceptable deviations (46%). Unacceptable deviations were similar for the few treatment plans that needed to be resubmitted more than once. <h3>Conclusion</h3> One third of patients required resubmission to meet protocol compliance criteria, demonstrating the continued need for expending resources on pretreatment QA for adjuvant pancreas cancer trials. Rigorous QA is of critical importance for clinical trials involving RT to ensure that the true impact of RT can be assessed. Moreover, RT QA serves as an educational process by training radiation oncologists on best practices.

Practice patterns for postoperative radiation therapy in patients with metastases to the long bones: a survey of the Japanese Radiation Oncology Study Group.

Evidence regarding postoperative radiation therapy (PORT) for metastases to the long bones is lacking. Characterizing the current practice patterns and identifying factors that influence dose-fractionation schedules are essential for future clinical trials. An internet-based survey of the palliative RT subgroup of the Japanese Radiation Oncology Study Group was performed in 2017 to collect data regarding PORT prescription practices and dose-fractionation schedules. Responders were also asked to recommend dose-fractionation schedules for four hypothetical cases that involved a patient with impending pathological fractures and one of four clinical features (poor prognosis, solitary metastasis, radio-resistant primary tumor or expected long-term survival). Responders were asked to indicate their preferred irradiation fields and the reasons for the dose fractionation schedule they chose. Responses were obtained from 89 radiation oncologists (67 institutions and 151 RT plans) who used 22 dose-fractionation schedules, with the most commonly used and recommended schedule being 30 Gy in 10 fractions. Local control was the most common reason for preferring longer-course RT. High-dose fractionated schedules were preferred for oligometastasis, and low-dose regimens were preferred for patients with a poor prognosis; however, single-fraction RT was not preferred. Most respondents recommended targeting the entire orthopedic prosthesis. These results indicated that PORT using 30 Gy in 10 fractions to the entire orthopedic prosthesis is preferred in current Japanese practice and that single-fraction RT was not preferred. Oligometastasis and poor prognosis influenced the selection of high- or low-dose regimens.

RT-04 Stereotactic irradiation for 2 - 3 cm brain metastases: A multicenter retrospective cohort study

Purpose: We retrospectively analyzed the treatment outcomes of Stereotactic irradiation (STI) for large size (2–3 cm) brain metastasis. Materials and methods: One hundred and sixty-nine lesions with 156 patients who underwent STI from January 1, 2013 to December 31, 2015 at 21 institutions participating in the Japanese Radiation Oncology Study Group were included in the study. Patients who had a history of whole-brain irradiation in the past and those who received whole-brain irradiation sequentially with STI were excluded. RANO-BM was used to evaluate the effect on each lesion, and the survival time or time to occurrence of local failure was defined as the number of months from the initial day of STI to the day of the events. Results: The median age was 66 (33–87) years. The median follow-up time was 14 (1–52) months. Male/female = 95/61 cases. The number of brain metastases was 1/2/3/4 or more = 93/35/14/14 cases. The median doses and fraction size were 30 Gy in 3 fractions. The primary site was lung/breast/colon or rectum/others = 95/14/14/33 cases. The median survival time was 16 months. A 1-year overall survival rate was 62% and a 1-year local control rate was 77%. Comparing the 1-year local control rate by the fraction size, single/3 or 4 /5 or more = 66/86/75%, the rate was better in the 3–4 fractions group (Log-rank test, p = 0.069). Cerebral necrosis (Grade 1/2/3/unknown = 9/10/8/3 cases) was observed in 30 lesions (18%), and the median time to diagnosis of brain necrosis was 9 (1–41) months. The incidence of necrosis in the single fraction cases was 29%, which was significantly higher than that in the fractionated irradiation cases (15%) (p = 0.039). Conclusion: Fractionated STI seems to be more favorable than single fraction STI for large brain metastases.

SP-0015: Genome wide association studies in radiation oncology

SP-0015: Genome wide association studies in radiation oncology

Retrospective Multicenter Study of Stereotactic Irradiation for Metastatic Brain Tumors in Japan

Stereotactic Irradiation (STI) has been increasingly utilized in the management for metastatic brain tumor. However, many studies show combined therapy with surgery or whole brain radiation therapy (WBRT). The purpose of this study is to report the multicenter outcome of metastatic brain tumors treated only by STIs in Japan. This was a retrospective multicenter analysis to review a total of 686 patients with 918 lesions which had diameter > 10 mm. STIs were performed among 26 institutions participated in Japanese Radiation Oncology Study Group (JROSG) from January 2013 to December 2015 treated with linear accelerators. Previous WBRT or surgery cases were all excluded. Local control (LC), overall survival (OS), and brain necrosis followed with diagnostic MRI were analyzed by Kaplan-Meier method. Patient characteristics were as follows. Median age was 67 years (range: 26-91). Median follow-up was 12.1 months (range: 0.5-55.5), Median KPS score/ tumor size/ number of lesion were 90/ 17mm/ 2, respectively. Primary sites were lung/ breast/ GI/ others = 527/ 106/ 114/ 171 cases, respectively. Median dose delivered was 31.5 Gy in 3 fractions (range 13.4-55 Gy). Treatment outcome was CR/ PR/ SD/ PR = 151/ 349/ 167/ 145 and death/ survive = 510/ 280, respectively. 1-year LC was 80.5%. Median survival was 15.8 months. 1-year OS was 58.9%. 1-year LC for tumor size of 3-4 cm was 59.2%. There was no difference in LC between single fraction and multiple fractions. Brain necrosis occurred at 6 months/ 1-year = 4.8%/ 10.6%. The incidence was linearly correlated with the time after treatment. Positive outcome of STI for brain metastases without WBRT or surgery was achieved. LC was a little poor with the tumor diameter > 3 cm. Brain necrosis occurred regardless of a tumor size and a delivered dose, and long-term follow-up is mandatory.

Optimal Androgen Deprivation Therapy Combined with Proton Beam Therapy for Prostate Cancer: Results from a Multi-Institutional Study of the Japanese Radiation Oncology Study Group.

Background: Androgen deprivation therapy (ADT) combined with radiation therapy benefits intermediate- and high-risk prostate cancer (PC) patients. The optimal ADT duration in combination with high-dose proton beam therapy (PBT) remains unknown. Methods: Intermediate- and high-risk PC patients treated with PBT combined with ADT for various durations were analyzed retrospectively. To assess the relationship between ADT and biochemical relapse-free (bRF) rate, Cox proportional hazards models including T stage, prostate specific antigen (PSA) level, Gleason score (GS), and total radiation dose were used. Results: In the intermediate-risk PC patients (n = 520), ADT use improved bRF (HR 0.49, 95% CI 0.26–0.93; p = 0.029), especially in those with multiple intermediate-risk factors (T2b–2c, PSA 10–20 ng/mL, and GS 7). In the high-risk PC patients (n = 555), a longer ADT duration (>6 months) conferred a benefit for bRF (HR 0.54, 95% CI 0.32–0.90; p = 0.018), which was most apparent in patients with multiple high-risk factors (T3a–4, PSA > 20 ng/mL, and GS ≥ 8) treated with ADT for ≥21 months. Conclusions: Short-term (≤6 months) ADT is beneficial for intermediate-risk PC patients, but likely unnecessary for those with a single risk factor, whereas ADT for >6 months is necessary for high-risk PC patients and ADT for ≥21 months might be optimal for those with multiple risk factors in combination of high-dose PBT.

Hypofractionated palliative volumetric modulated arc radiotherapy with the Radiation Oncology Study Group 8502 \u201cQUAD shot\u201d regimen for incurable head and neck cancer

BackgroundTo review a single institutional experience of the Radiation Therapy Oncology Group (RTOG) 8502 “QUAD shot” regimen using volumetric modulated arc radiotherapy (VMAT) for incurable head and neck cancer (HNC).MethodsThirty-four consecutive patients with HNC were treated with at least one cycle of the RTOG 8502 regimen. Treatment plans included the use of VMAT with 6 MV photons generated by a linear accelerator. Two daily fractions of 3.7 Gy were delivered with an interval of at least 6 h for 2 consecutive days, totaling 14.8 Gy over 4 fractions. This was repeated every 3–4 weeks for a total of three cycles. No concurrent systemic therapy was performed.ResultsThe number of completed cycles was 1 in 6 (18%) patients, 2 in 5 (15%), and 3 in 23 (68%). Tumor response was achieved in 29 (85%) patients and symptom relief in 20 (77%) of 26 patients. Overall response (tumor response or symptom relief) was achieved in 32 (94%) patients. All patients who received 2 or more treatment cycles achieved overall response. Median overall survival (OS) was 5.7 months. Multivariate analysis revealed that completion of all three treatment cycles was significantly associated with better OS (P = 0.002). Grade 2 toxicity was observed in four (12%) patients, but no acute Grade ≥ 3 or late toxicity was observed.ConclusionsThe RTOG 8502 “QUAD shot” regimen using VMAT is effective for incurable HNC with highly reduced toxicity. Treatment with multiple cycles is recommended for better treatment response and/or survival.