[A preliminary safety study of hypofractionated radiotherapy for local prostate cancer]

Institute of Oncology of Vilnius University has initiated a randomized clinical trial with the aim to evaluate the effectiveness and toxicity of conventional fractionated (37 fractions, 2.0 Gy per fraction, a total dose of 74 Gy) and hypofractionated (13 fractions, 3.0 Gy per fraction, and 4 fractions at 4.5 Gy per fraction, a total dose of 57 Gy) radiotherapy. The goal of preliminary safety analysis was to compare the acute radiation toxicity in investigated and control groups. A total of 22 patients have been enrolled in this trial; there were 11 patients in each investigated group. Grade IV acute bladder radiation toxicity according to Radiation Therapy Oncology Group (RTOG) toxicity criteria was observed in one control group patient. No grade III acute radiation toxicity was observed. Grade II acute radiation toxicity was observed in 2 patients from hypofractionated radiotherapy group and in 3 from conventional radiotherapy group. Grade I-II acute radiation toxicity was observed in all patients of investigated and control groups. A statistically significant decrease of grade I bladder and rectal toxicity in the hypofractionated arm and grade I bladder toxicity in the conventional arm was observed. Other differences were not significant. A comparatively small number of acute reactions in the patients' group treated with hypofractionated radiotherapy show the safety of the method applied and enable the continuation of this trial.