The 5-year outcomes of moderately hypofractionated radiotherapy (66Gy in 22 fractions, 3 fractions per week) for localized prostate cancer: a retrospective study.

Abstract

Hypofractionated radiotherapy using fewer and larger fractional doses may be more beneficial than conventional external-beam radiotherapy for localized prostate cancer. We evaluated the 5-year outcomes of moderately hypofractionated radiotherapy for localized prostate cancer. We retrospectively evaluated 195 patients with localized prostate cancer (T1-3N0M0) who underwent intensity-modulated radiotherapy (IMRT) (66Gy delivered in fractions of 3Gy every other weekday) between May 2005 and December 2011. Patients received androgen deprivation therapy depending on the perceived intermediate or high risk of their disease. A prostate-specific antigen nadir +2.0ng/ml indicated biochemical failure. We assessed toxicity using the Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria, and patient-reported outcomes using the Expanded Prostate Cancer Index Composite (EPIC). The risk classifications (proportion) were low risk (13.8%), intermediate risk (35.9%), and high risk (50.3%). The median follow-up was 69months. Thirteen (6.66%) patients experienced biochemical failure within a median of 40months (interquartile range, 25-72months). The 5-year overall survival rate and no biological evidence of disease rate were 97.7% and 92.4%, respectively. Based on the RTOG/EORTC criteria, no patient experienced acute or late toxicity of grade 3 or higher. The EPIC scores revealed significant differences in the average value of all domains (p<0.01). At 1month postradiotherapy completion, the general urinary and bowel domain scores had decreased, but these scores returned to baseline level by 3months post radiotherapy. The moderately hypofractionated radiotherapy protocol yielded short-term satisfactory clinical outcomes with acceptable toxicity.