Carbon-ion Radiotherapy for Prostate Cancer: Analysis of Morbidities and Change in Health-related Quality of Life

Aim: To prospectively evaluate the feasibility of carbon-ion radiotherapy (C-ion RT) for prostate cancer using a new compact-sized accelerator. Patients and Methods: Seventy-six patients underwent C-ion RT at our center using a recommended dose fractionation of 57.6 GyE in 16 fractions established at the National Institute of Radiological Sciences. Health-related Quality of Life (HRQOL) assessment was also performed using the Medical Outcome Study 8-items Short Form Health Survey (SF-8) questionnaire. Results: The median follow-up time was 51 months (range=8-58 months). Grade 2 gastrointestinal and genitourinary complications developed in 1 (1.3%) and 5 (6.6%) patients, respectively. Recurrences occurred in 4 patients, and the 4-year biochemical relapse-free rate was 94.6%. The HRQOL scores after C-ion RT were objectively well-maintained. Conclusion: Irrespective of the small number of patients of the study, C-ion RT for prostate cancer using the first commercial-based accelerator reproduced the toxicity outcomes at the NIRS.