Carbon ion radiotherapy for prostate cancer

Analysis on the results of hypofractionated conformal carbon ion radiotherapy (C-ion RT) for localized prostate cancer was performed, with special regard to normal tissue morbidity, biochemical relapse-free rate (bNED), and patient survival. Three hundreds and seventy-four prostate cancer patients who received C-ion RT established through two preceding dose-escalation studies were analyzed in regard to toxicity, survival, and bNED. Concerning radiation morbidity, no grade 3 or higher toxicities were observed either in the rectum or genitourinary system (GU), and the incidences of grade 2 rectum and GU morbidity were only 1.9% and 6.8%, respectively. Overall bNED at 5 years was 88.3%, with only two local recurrences. Gleason's score and T-stage were significant prognostic factors for bNED, but initial prostatic specific antigen (PSA) showed no definitive influence on bNED. The duration of hormonal therapy also had a strong impact on biochemical control in high-risk patients, but it appeared possible to apply C-ion RT with short-course hormonal therapy to intermediate-risk patients. C-ion RT with the established dose fractionation regimen yielded satisfactory bNED with only two local recurrences, and with minimal morbidity. (author)