Journal of Radiation Research最新文献

{"title":"Dosimetric comparison of scanned proton therapy and volumetric modulated arc therapy in isodose-prescribed stereotactic body radiotherapy for lung cancer.","authors":"Yuki Tominaga, Hiromitsu Endo, Takahiro Kato, Yushi Wakisaka, Tatsuyuki Higashikawa, Masao Murakami, Michinori Yamamoto","doi":"10.1093/jrr/rraf091","DOIUrl":"10.1093/jrr/rraf091","url":null,"abstract":"<p><p>This study evaluated the feasibility of pencil beam scanning (PBS) proton therapy for stereotactic body radiotherapy using an isodose prescription in patients with isolated early-stage lung cancer, comparing dose-volume metrics with those of volumetric modulated arc therapy (VMAT). Treatment plans were generated for 10 patients with tumors located at least 2 cm from the trachea. Each plan prescribed 48 Gy(RBE) in four fractions with a 60% isodose prescription. Both multi-field optimized and single-field optimized PBS plans used four fields, while VMAT plans used two coplanar arcs. Plan robustness was assessed by simulating setup errors of ±5.0 mm and density uncertainties of ±3.5%, with worst-case target coverage also analyzed. Comparisons among the three planning strategies employed Bonferroni-adjusted multiple comparisons for target coverage, robustness, and organ-at-risk doses. PBS achieved target coverage comparable to VMAT, with similar D98% (63.2 ± 1.3 GyRBE vs. 64.0 ± 1.6 Gy; P = 0.12), mean doses (73.2 ± 0.8 GyRBE vs. 73.7 ± 1.2 Gy; P = 0.21), and robustness (D98%: 50.2 ± 0.9 GyRBE vs. 50.3 ± 1.1 Gy; P = 0.77). For the normal lung, PBS significantly reduced low-dose exposure up to V10Gy, whereas VMAT was more effective in reducing doses from V20Gy to the prescription level. All evaluated organ-at-risks received significantly lower mean doses with PBS than with VMAT (P < 0.05). Under a 60% isodose prescription for lung stereotactic body radiotherapy, multi-field optimized-based PBS proton therapy provides target coverage and robustness comparable to VMAT while offering superior normal tissue sparing.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"236-247"},"PeriodicalIF":2.1,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13019148/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146125395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Willingness to engage in nuclear or radiological emergency response among medical personnel at four university hospitals in Kyushu, Japan.","authors":"Arkhat Omarbek, Keita Iyama, Takanobu Otaguro, Goro Tajima, Kazunori Yamashita, Osamu Tasaki","doi":"10.1093/jrr/rraf092","DOIUrl":"10.1093/jrr/rraf092","url":null,"abstract":"<p><p>Following the Fukushima Daiichi Nuclear Power Plant accident, Japan enhanced its nuclear disaster preparedness framework. However, personnel shortages stemming from fear and anxiety persist as a critical issue during such disasters. This study investigated the willingness of medical professionals at four university hospitals in Kyushu to participate in nuclear disaster response activities and explored factors influencing this willingness. A cross-sectional web-based survey was conducted among staff at Nagasaki, Kyushu, Saga and Kagoshima University Hospitals. Participants answered 19 questions assessing their willingness to participate in nuclear or radiological emergency response and associated psychosocial and occupational factors. Multiple regression analysis was used to identify predictors of willingness (Q1). A total of 378 valid responses were analyzed. Demographic variables, including age, sex, occupation and disaster experience, did not significantly influence willingness. However, interest in nuclear or radiological emergencies (β =0.383, P < 0.05), Incentives (β =0.249), Family understanding (β =0.116) and Occupational norms (β =0.114) were positively associated with willingness. Conversely, Anxiety (β = -0.151), Expectation of routine training (β = -0.138) and Perceived frequency of nuclear disasters (β = -0.104) were negatively associated with willingness. Medical staff's willingness to respond to nuclear or radiological emergencies is influenced more by psychological and occupational perceptions than by demographic factors. Interventions such as incentive programs, family support initiatives, targeted training and anxiety-reduction strategies may enhance preparedness for and participation in future nuclear or radiological emergencies.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"182-190"},"PeriodicalIF":2.1,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13019142/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146132193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geographic access to radiotherapy facilities in Japan.","authors":"Yuhei Koike, Satoaki Nakamura, Hodaka Numasaki, Noboru Tanigawa","doi":"10.1093/jrr/rrag004","DOIUrl":"10.1093/jrr/rrag004","url":null,"abstract":"<p><p>Daily attendance requirements for radiotherapy (RT) make geographic accessibility a critical determinant of treatment adherence and completion. Although facility surveys indicate that advanced modalities such as intensity-modulated radiotherapy (IMRT) and brachytherapy are concentrated in urban centers, precise nationwide quantification of the resulting patient travel burden remains lacking. This study provides the first nationwide, modality-stratified assessment of geographic access to RT in Japan. Using the Open Source Routing Machine and a high-resolution dataset of 176 964 household-weighted 1-km mesh centroids, we calculated driving times to the nearest external-beam radiotherapy (EBRT), IMRT and brachytherapy facilities. Beyond standard distribution metrics, we generated high-resolution 'penalty maps' to quantify the incremental time tax imposed by advanced modality requirements. Although EBRT access was uniformly short nationwide, with a median travel time of 6.48 min, this increased to 8.26 min for IMRT and 14.06 min for brachytherapy. Crucially, the proportion of the population facing poor access (≥120 min) doubled from 0.24% for EBRT to 0.48% for brachytherapy. The spatial analysis identified specific 'newly poor-access' areas-regions that are accessible for EBRT but become remote when advanced care is needed-forming coherent geographic clusters in mountainous and island zones. These findings demonstrate that modality requirements introduce meaningful inequities despite strong national EBRT infrastructure. These indicators provide a vital evidence base for spatially optimizing resources to mitigate travel burdens for Japan's aging, mobility-limited population.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"259-265"},"PeriodicalIF":2.1,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13019145/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147290283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Utilization of radiotherapy and hypofractionated radiotherapy in Japan: long-term trends and the influence of COVID-19 pandemic.","authors":"Kazuya Takeda, Rei Umezawa, Takaya Yamamoto, Noriyoshi Takahashi, Shinsaku Okuda, Katsumasa Nakamura, Keiichi Jingu","doi":"10.1093/jrr/rraf088","DOIUrl":"10.1093/jrr/rraf088","url":null,"abstract":"<p><p>During the coronavirus disease 2019 (COVID-19) pandemic, a short-term decline in radiotherapy use was reported. In this study, we investigated long-term changes in the use of radiotherapy and hypofractionated radiotherapy before and after the COVID-19 pandemic period in Japan and assessed whether the pandemic influenced the adoption of hypofractionation. We obtained data for analysis from the National Database Open Data for fiscal years (FYs) 2014 to 2023. For the 5 years from FY2019 to FY2023, with detailed monthly data available, we used interrupted time series (ITS) analysis to examine changes in the level and slope of claims at the boundaries of the baseline, pandemic and post-pandemic periods. During the 10-year study period, the number of radiotherapy claims increased by an average of 1.6% per year. In FY2020, the peak of the COVID-19 pandemic, the number of radiotherapy claims decreased by 2.0% compared to the previous year. The number of claims for extra fees for hypofractionated radiotherapy for breast and prostate cancer showed a steady increase, except for a temporary decline around the April 2022 policy change in payment requirements for prostate cancer. In the ITS analysis, there were no significant changes in the level and slope of claims for radiotherapy and extra fees for hypofractionated radiotherapy at the onset of the pandemic. In conclusion, the impact of the COVID-19 pandemic on the utilization of radiotherapy in Japan was minimal, and the use of hypofractionated radiotherapy showed a steady increase throughout this period.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"221-227"},"PeriodicalIF":2.1,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13019144/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146086258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning-DeepSurv prediction model integrating mpMRI radiomics and genomic biomarkers for BCR-free survival and tumor response in prostate radiotherapy.","authors":"Hossein Taheri, Mohammadbagher Tavakoli, Maryam Farghadani, Sheyda Lafzlenjani, Hamed Taheri","doi":"10.1093/jrr/rraf079","DOIUrl":"10.1093/jrr/rraf079","url":null,"abstract":"<p><p>The purpose of this study was to design a radiogenomics machine learning-DeepSurv model for biochemical recurrence-free (BCR-free) survival and treatment response (TR) prediction for radiotherapy (RT) of prostate cancer (PCa). In this study, radiomic features were extracted from pre and post treatment multiparametric MRI (mpMRI), including T2-weighted (T2W), diffusion-weighted MR imaging (DWI) and apparent diffusion coefficient (ADC). Also, genomic biomarkers such as Ki-67 (a cell proliferation marker reflecting tumor growth activity and also prognostic information in cancer progression), PTEN (tumor suppressor gene regulating cell growth and survival, have a prominent role for TR and cancer progression) and Decipher (a genomic signature predicting cancer recurrence risk and TR based on gene expression patterns) were collected. Radiomics feature selection and dimensionality reduction methods were employed, followed by training machine learning (ML) models. Moreover, time to event data and survival models including Random Survival Forest (RSF) and DeepSurv neural networks were used. For model performance, the concordance index (C-index) and integrated Brier score (IBS), and for improving interpretability, the SHapley Additive exPlanations (SHAP) were applied. Radiomic feature of MRI including Kurtosis demonstrated a near-perfect positive correlation with Ki-67 expression (r = 0.64), however skewness showed a strong negative correlation with PTEN status (r = -0.88). Entropy and kurtosis of MRI were also highly correlated with the Decipher genomic risk score (r = 0.90 and r = -0.96, respectively). The integrated ML-DeepSurve model performance overall F1-score was 0.93 for TR. The model also offered robust stratification for patients based on BCR-free survival probability. Our findings underscore the potential of radiogenomic signatures as non-invasive biomarkers to personalized PCa RT decisions and provide a novel clinically explainable predictive model based on radiomic and molecular biomarkers for BCR-free survival and TR of mentioned cancer.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"84-94"},"PeriodicalIF":2.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12856028/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145781413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A national survey of the clinical practice of surface-guided radiation therapy in Japan.","authors":"Ryohei Yamauchi, Masahide Saito, Hironori Kojima, Yusuke Ueshima, Chie Kurokawa, Naoki Tohyama, Masahiko Kurooka, Shinobu Kumagai, Eriko Saito, Masataka Sakamoto, Takayuki Kanai, Hidekazu Suzuki, Tatsunori Saito, Tomoki Kitagawa, Makoto Sasaki, Hiroki Katayama, Yoshinobu Shimohigashi, Yoshifumi Oku, Naoki Hayashi, Takeshi Ohno, Hiroshi Onishi","doi":"10.1093/jrr/rraf086","DOIUrl":"10.1093/jrr/rraf086","url":null,"abstract":"<p><p>The purpose of this study was to evaluate the diffusion of surface-guided radiation therapy (SGRT), implementation of quality control and quality assurance strategies, established clinical workflows and user perceptions regarding the benefits and limitations of SGRT in routine practice. From October to December 2024, we surveyed 880 radiotherapy institutions in Japan regarding institutional characteristics, quality assurance/quality control, computed tomography simulation, treatment procedures and general questions regarding SGRT. The survey was distributed via mailing list and through vendors, and administered via Google Forms. A total of 292 institutions responded, corresponding to a response rate of 33%. Ninety-eight institutions reported introducing SGRT, and 50 institutions had introduced it after 2022. The highest usage rate of SGRT in breast treatment was 87%. Approximately half of the institutions performed daily checks of SGRT and radiation isocenter coincidence, as well as static accuracy, whereas 6% did not perform these checks at all. The primary functions of the SGRT system were patient positioning (94%), respiratory management (78%), patient monitoring (76%) and skin marker-less techniques (69%). Many institutions reduced or eliminated skin marking, citing simplified workflows and reduced setup time. Many respondents observed that SGRT implementation reduced both setup and treatment times for breast/chest, abdomen/pelvis and extremity procedures. SGRT has been widely embraced in Japan, offering notable clinical and workflow benefits. However, because participation in this survey was voluntary, the results may overrepresent institutions with greater awareness or adoption of SGRT. Greater standardization, broader insurance coverage and ongoing technological advancements are essential to fully realize its advantages.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"134-147"},"PeriodicalIF":2.1,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12856029/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145985052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association between pelvic bone marrow dosimetry and acute hematologic toxicity during concurrent chemoradiotherapy for gynecologic malignancies.","authors":"Chengliang Zhou, Jie Chen","doi":"10.1093/jrr/rraf084","DOIUrl":"10.1093/jrr/rraf084","url":null,"abstract":"<p><p>Pelvic radiotherapy for gynecologic malignancies damages the primary active bone marrow reservoir, inducing hematologic toxicity exacerbated by chemotherapy. Optimizing pelvic bone marrow dose-volume constraints is critical to mitigate myelosuppression and maintain treatment efficacy. The present retrospective cohort study analyzed patients with gynecological cancer (n = 61) undergoing concurrent chemoradiotherapy between August 2021 and August 2024. Associations between pelvic bone marrow (PBM) dose-volume parameters and acute hematologic toxicity (AHT) were systematically evaluated. All patients received intensity-modulated radiotherapy encompassing pelvic lymph node regions, with weekly complete blood count monitoring during and for 2 weeks after treatment. The overall incidence of AHT was 70.5% (43/61), with grade ≥ 2 and ≥ 3 AHT occurring in 63.9% (39/61) and 30.0% (14/61) of patients, respectively. Multivariate analysis identified PBM-V15 as an independent predictor of grade ≥ 2 AHT [odds ratio (OR), 2.653; 95% CI, 1.054-6.682; P = 0.038], with an optimal cutoff threshold of 80.44% [area under the curve (AUC), 0.854]. Notably, a lower PBM (LPBM)-V5 specifically predicted grade ≥ 3 AHT (OR, 1.425; 95% CI, 1.022-1.987; P = 0.037), with a threshold of 91.25% (AUC, 0.695). Implementing bone marrow-sparing strategies by restricting PBM-V15 to <80.44% significantly reduced the grade ≥ 2 AHT risk, while a stringent LPBM-V5 constraint (< 91.25%) was pivotal for preventing severe (grade ≥ 3) AHT. These dose-volume parameters should be incorporated into optimization protocols for pelvic radiotherapy in gynecological malignancies.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"121-133"},"PeriodicalIF":2.1,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12856034/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145971025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abscopal-like antitumor effect induced by localized low-temperature plasma application of normal tissue in mice.","authors":"Ryo Ono, Ryota Sumitomo, Kengo Wada, Reima Jinno, Hideyuki Yanai","doi":"10.1093/jrr/rraf077","DOIUrl":"10.1093/jrr/rraf077","url":null,"abstract":"<p><p>We have previously reported that the localized application of gaseous plasma to normal tissues suppresses distant tumor growth in mice, resembling the abscopal effect of radiotherapy. Plasma, a partially ionized gas generated by a high-voltage electrical discharge, is fundamentally distinct from ionizing radiation and produces diverse reactive oxygen and nitrogen species that interact with biological tissues. This study examined the abscopal-like effects of normal tissue plasma treatment in BALB/c mice with subcutaneous Colon 26 tumors. The left dorsal skin, 2-3 cm from the tumor, was exposed to plasma for 10 min per day for 5 consecutive days, which delayed the growth of distant tumors. Similar tumor suppression was observed with abdominal exposure, indicating that the effect was not site-specific. In C.B-17 SCID mice (lacking T and B cells) and BALB/c nu/nu mice (lacking T cells), dorsal treatment did not suppress tumor growth, suggesting that T cells are likely involved in the response. Flow cytometric analysis of tumor-infiltrating immune cells in BALB/c mice revealed significant reductions in macrophages and increases in monocytes, with a possible but nonsignificant increase in dendritic cells. No consistent changes were detected in CD8+ T-cell proportion or ICOS (inducible T-cell costimulatory) expression. However, the lack of antitumor effects in immunodeficient mice suggests that CD8+ T cells are involved.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"50-58"},"PeriodicalIF":2.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12856031/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145781303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the capability of large language models in radiotherapy through professional certification examinations in Japan.","authors":"Noriyuki Kadoya, Yoshiyuki Takahashi, Seiya Koga, Hikaru Tanno, Kazuhiro Arai, Shohei Tanaka, Yoshiyuki Katsuta, Hinako Harada, So Omata, Takaya Yamamoto, Rei Umezawa, Ken Takeda, Keiichi Jingu","doi":"10.1093/jrr/rraf083","DOIUrl":"10.1093/jrr/rraf083","url":null,"abstract":"<p><p>Large language models (LLMs), such as ChatGPT and Grok, have rapidly advanced in natural language understanding and are increasingly being applied to specialized fields, including medicine. In this study, we evaluated the domain-specific knowledge of LLMs in radiotherapy by assessing their performance on three certification examinations in Japan: the Japanese Medical Physicist Examination, the Japanese Board Examination for Radiologists and the Japanese Board Examination for Radiation Oncologists. We assessed five LLMs-ChatGPT-5, ChatGPT-5 Pro, Grok 4, Grok 4 heavy and Gemini 2.5 Pro-by inputting all multiple-choice questions from these exams into each model and recording their responses. The AI-generated answers were compared with reference answers determined by experienced medical physicists and radiation oncologists. The results demonstrated average accuracies of 84.7 ± 2.0% (ChatGPT-5), 94.7 ± 2.1% (ChatGPT-5 Pro), 78.4 ± 1.2% (Grok 4), 81.6 ± 2.2% (Grok 4 heavy) and 88.9 ± 1.2% (Gemini 2.5 Pro). All models achieved over 75% accuracy, with ChatGPT-5 Pro consistently outperforming others, attaining an average accuracy exceeding 90% across all examinations. These findings highlight the strong potential of advanced LLMs, particularly ChatGPT-5 Pro, for future integration into radiotherapy-related applications such as automated contouring and treatment planning support.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"114-120"},"PeriodicalIF":2.1,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12856024/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145949024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends in hypofractionated radiotherapy use among patients with breast or prostate cancer: a multicenter study in Osaka, Japan.","authors":"Toshiki Ikawa, Toshitaka Morishima, Kayo Nakata, Yoshihiro Kuwabara, Kenji Kishimoto, Naoyuki Kanayama, Masahiro Morimoto, Koji Konishi, Isao Miyashiro","doi":"10.1093/jrr/rraf082","DOIUrl":"10.1093/jrr/rraf082","url":null,"abstract":"<p><p>The uptake of hypofractionated radiotherapy in Japan is not well documented. This study examined trends in the proportion of patients with breast or prostate cancer who received hypofractionated radiotherapy, using hospital-based cancer registry data linked to Diagnostic Procedure Combination records from 69 institutions in Osaka Prefecture (diagnosis years: 2019-23). Eligible patients included 6475 women with unilateral breast cancer (pTisN0M0, pT1-2N0M0 or cT1-2N0M0 before neoadjuvant therapy) who underwent partial mastectomy and radiotherapy at the same hospital and 3274 men with cT1-3N0M0 prostate cancer treated with external-beam radiotherapy without surgery or brachytherapy. The use of hypofractionated radiotherapy was determined through insurance claims. Among the patients with breast cancer, the proportion of those who received hypofractionated radiotherapy increased from 41% in 2019 to 81% in 2023. In 2023, this proportion was highest at facilities with high radiotherapy volume (95%), followed by those with medium (84%) and low (67%) volumes. Among the patients with prostate cancer, the proportion of those who received hypofractionated radiotherapy (hypofractionated intensity-modulated radiotherapy or stereotactic body radiotherapy) increased from 25% in 2019 to 48% in 2023, although the increase slowed after 2021. In 2023, hypofractionated radiotherapy use reached 79% at high-volume facilities, while proportions were lower at medium- (30%) and low-volume (17%) facilities. Hypofractionated radiotherapy use has increased in patients with breast and prostate cancers. However, its adoption in prostate cancer treatment remains limited, particularly in medium- and low-volume facilities. These findings suggest that certain barriers limit its implementation and highlight the need to address them.</p>","PeriodicalId":16922,"journal":{"name":"Journal of Radiation Research","volume":" ","pages":"104-113"},"PeriodicalIF":2.1,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12856026/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145966408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}