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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. [ABSTRACT FROM AUTHOR]

Highlights • We analyzed 64 LAPC patients treated with C-ion RT at single institution. • The median survival time and 2-year OS were 25.1 months and 53%. • Only four patients experienced acute grade 3 toxicities. • C-ion RT for LAPC showed relatively favorable outcome and limited toxicity. Abstract Purpose The aim of this study was to evaluate the efficacy and safety of carbon-ion radiotherapy (C-ion RT) for unresectable locally advanced pancreatic cancer (LAPC). Methods and materials Patients with LAPC treated with definitive C-ion RT between April 2014 and July 2017 were analyzed retrospectively. The prescribed dose was 55.2 Gy (relative biological effectiveness [RBE] weighted absorbed dose) in 12 fractions. Overall survival (OS), local control (LC), progression free survival (PFS), and toxicity were evaluated. Results Sixty-four patients were enrolled. All patients completed planned course of C-ion RT. The median follow-up time for survivors from the initiation of C-ion RT was 24.4 months (range, 5.1–46.1 months). Median survival time was 25.1 months. Two-year OS, LC, and PFS were 53% (95% confidence interval [CI], 39%–66%), 82% (95% CI, 66%–91%), and 23% (95% CI, 14%–36%), respectively. Four patients experienced acute grade 3 toxicities including 3 gastrointestinal (GI) toxicities. There was no grade 3 or more late toxicity. Conclusions The clinical results of C-ion RT for LAPC at our institution were comparable to those of a recent multi-institutional analysis. [ABSTRACT FROM AUTHOR]

Background and purpose A multi-institutional observational study (J-CROS1501PR) has been carried out to analyze outcomes of carbon-ion radiotherapy (CIRT) for patients with prostate cancer. Patients and methods Data of the patients enrolled in prospective studies of following 3 CIRT institutions were analyzed: National Institute of Radiological Sciences (NIRS; Chiba, Japan), Gunma University Heavy Ion Medical Center (GHMC; Gunma, Japan), and Ion Beam Therapy Center, SAGA HIMAT Foundation (HIMAT; Saga, Japan). Endpoints of the clinical trial are biochemical recurrence-free survival (bRFS), overall survival (OS), cause-specific survival (CSS), local control rate (LCR), and acute/late adverse effects. Results A total of 2157 patients’ data were collected from NIRS ( n = 1432), GHMC ( n = 515), and HIMAT ( n = 210). The number of patients in low-risk, intermediate-risk, and high-risk groups was 263 (12%), 679 (31%), and 1215 (56%), respectively. The five-year bRFS in low-risk, intermediate-risk, and high-risk patients was 92%, 89%, and 92%, respectively. The five-year CSS in low-risk, intermediate-risk, and high-risk patients was 100%, 100%, and 99%, respectively. The incidence of grade 2 late GU/GI toxicities was 4.6% and 0.4%, respectively, and the incidence of ⩾G3 toxicities were 0%. Conclusions Favorable overall outcomes of CIRT for prostate cancer were suggested by the analysis of the first multi-institutional data. [ABSTRACT FROM AUTHOR]

Purpose The aim of this study was to clarify the incidence, clinical risk factors, and dose–volume relationship of upper gastrointestinal (GI) ulcer after carbon-ion radiotherapy (C-ion RT) for pancreatic cancer. Materials and methods Fifty-eight pancreatic cancer patients were treated with C-ion RT from April 2014 to December 2015. The total dose was 55.2 Gy (RBE) in 12 fractions. D 2cm3 of GI tracts were restricted under 46 Gy (RBE); RBE-weighted absorbed dose. The association between dosimetric parameters (V 10–50 , D max , D 1cm3 , D 2cm3 ) and GI ulcer was examined using Spearman’s correlation. The incidence of GI ulcer was compared between the two groups divided by the cutoff value. Results Twelve patients (21%) experienced gastric ulcer including only one (2%) grade 3 ulcer. There was no grade 4/5 toxicity or duodenal ulcer. V 10–30 was significantly associated with gastric ulcer. The 1-year estimated risk of gastric ulcer for the determined cutoff values were 51% vs. 10% (V 10 , ⩾102 cm 3 or less), 42% vs. 9% (V 20 , ⩾24 cm 3 or less), 34% vs. 4% (V 30 , ⩾6 cm 3 or less). Conclusions The incidence of GI ulcer after C-ion RT was very low with the dose constraint of D 2cm3 <46 Gy (RBE). To further minimize the risk of GI ulcer, V 10–30 should also be reduced. [ABSTRACT FROM AUTHOR]