Management of patients with bone sarcoma who are unsuitable for surgery is challenging. We aimed to analyze the clinical outcomes among such patients who were treated with carbon ion radiotherapy (C-ion RT). We reviewed the medical records of the patients treated with C-ion RT between April 2011 and February 2019 and analyzed the data of 53 patients. Toxicities were classified using the National Cancer Institute’s Common Terminology Criteria for Adverse Events (Version 4.0). The median follow-up duration for all patients was 36.9 months. Histologically, 32 patients had chordoma, 9 had chondrosarcoma, 8 had osteosarcoma, 3 had undifferentiated pleomorphic sarcoma, and 1 had sclerosing epithelioid fibrosarcoma. The estimated 3-year overall survival (OS), local control (LC), and progression-free survival (PFS) rates were 79.7%, 88.6%, and 68.9%, respectively. No patients developed grade 3 or higher acute toxicities. Three patients developed both grade 3 radiation dermatitis and osteomyelitis, one developed both grade 3 radiation dermatitis and soft tissue infection, and one developed rectum-sacrum-cutaneous fistula. C-ion RT showed favorable clinical outcomes in terms of OS, LC, and PFS and low rates of toxicity in bone sarcoma patients. These results suggest a potential role for C-ion RT in the management of this population.

Background and purpose: Favorable clinical outcomes of carbon-ion radiotherapy for pelvic recurrence of rectal cancer have been described by previous prospective phase I/II and II studies; however, these studies were performed at a single institution. Therefore, we conducted a prospective observational study aimed at exploring whether carbon-ion radiotherapy for post-operative pelvic recurrence of rectal cancer provides a less invasive local treatment strategy with higher cure rates than other anticancer treatments. Materials and methods: Patients (1) with pelvic recurrence of rectal cancer, as confirmed by histology or diagnostic imaging; (2) without distant metastasis; (3) who had undergone curative resection of their primary disease and regional lymph nodes, without gross or microscopic residual disease; and (4) with radiographically measurable tumors were included in this study. The total carbon-ion radiotherapy dose for all patients was 73.6 Gy [relative biological effectiveness (RBE)] administered in 16 fractions once daily for 4 days a week (Tuesday to Friday). Results: A total of 28 patients were enrolled between October 2011 and July 2017. The median follow-up duration was 38.9 months. The 3-year overall survival, local control, and progression-free survival rates were 92, 86, and 31%, respectively. At the time of the analysis, 4 patients had local recurrence, and 7 had died of rectal cancer. None of the patients developed grade 3 or higher acute toxicities. Late toxicities occurred in 2 and 7 patients who developed grade 3 pelvic infection and grade 2 peripheral neuropathy, respectively. Conclusion: Carbon-ion radiotherapy for pelvic recurrence of rectal cancer showed favorable clinical outcomes and is a highly curative and less invasive local treatment.

Systemic chemotherapy has significantly improved in recent years. In this study. the clinical impact of carbon-ion radiotherapy (CIRT) with concurrent chemotherapy for locally advanced unresectable pancreatic cancer (URPC) was evaluated. Methods: Patients with URPC who were treated with CIRT between January 2016 and December 2020 were prospectively registered and analyzed. The major criteria for registration were (1) diagnosed as URPC on imaging; (2) pathologically diagnosed adenocarcinoma; (3) no distant metastasis; (4) Eastern Cooperative Oncology Group performance status of 0–2; (5) tumors without gastrointestinal tract invasion; and (6) available for concurrent chemotherapy. Patients who received neoadjuvant chemotherapy (NAC) for more than one year prior to CIRT were excluded. Results: Forty-four patients met the inclusion criteria, and thirty-seven received NAC before CIRT. The median follow-up period of living patients was 26.0 (6.0–68.6) months after CIRT. The estimated two-year overall survival, local control, and progression-free survival rates after CIRT were 56.6%, 76.1%, and 29.0%, respectively. The median survival time of all patients was 29.6 months after CIRT and 34.5 months after the initial NAC. Conclusion: CIRT showed survival benefits for URPC even in the multiagent chemotherapy era.

We aimed to clarify the accuracy of rigid image registration and deformable image registration (DIR) in carbon-ion radiotherapy (CIRT) for pancreatic cancer. Six patients with pancreatic cancer who were treated with passive irradiation CIRT were enrolled. Three registration patterns were evaluated: treatment planning computed tomography images (TPCT) to CT images acquired in the treatment room (IRCT) in the supine position, TPCT to IRCT in the prone position, and TPCT in the supine position to the prone position. After warping the contours of the original CT images to the destination CT images using deformation matrices from the registration, the warped delineated contours on the destination CT images were compared with the original ones using mean displacement to agreement (MDA). Four contours (clinical target volume (CTV), gross tumor volume (GTV), stomach, duodenum) and four registration algorithms (rigid image registration [RIR], intensity-based DIR [iDIR], contour-based DIR [cDIR], and a hybrid iDIR-cDIR ([hDIR]) were evaluated. The means ± standard deviation of the MDAs of all contours for RIR, iDIR, cDIR, and hDIR were 3.40 ± 3.30, 2.2 1± 2.48, 1.46 ± 1.49, and 1.46 ± 1.37 mm, respectively. There were significant differences between RIR and iDIR, and between RIR/iDIR and cDIR/hDIR. For the pancreatic cancer patient images, cDIR and hDIR had better accuracy than RIR and iDIR.

Purpose: The feasibility and safety of re-irradiation with carbon ion beams for locally recurrent unresectable pancreatic cancer (URPC) after carbon ion radiotherapy (CIRT) was evaluated. Methods: Medical records from patients with re-irradiated URPC who were treated with CIRT between November 2017 and February 2019 were reviewed. Inclusion criteria were (1) isolated local recurrence after CIRT, (2) URPC, and (3) tumor located at least 3 mm from the gastrointestinal tract. The first and second CIRT irradiation doses were 55.2 Gy (relative biological effectiveness) in 12 fractions. Results: Ten patients met the inclusion criteria. The median follow-up period was 25.5 months (range, 16.0–69.1) after the first CIRT and 8.9 months (range, 6.4–18.9) after the second CIRT. The median interval between the initial CIRT and the local recurrence was 15.8 months (range, 8.0–50.1). One patient developed grade 3 diarrhea immediately after the second CIRT; no other grade 3 or higher adverse events were attributed to CIRT. The estimated 1-year overall survival, local control, and progression-free survival rates after the second CIRT were 48%, 67%, and 34%, respectively. Conclusion: Repeated CIRT is feasible with acceptable toxicity for selected patients with locally advanced URPC after CIRT.