Toxicity after three-dimensional radiotherapy for prostate cancer on RTOG 9406 dose Level V

Purpose: This is the first report of toxicity outcomes at dose Level V (78 Gy) on Radiation Therapy Oncology Group 9406 for Stages T1-T2 adenocarcinoma of the prostate. Methods and Materials: A total of 225 patients were entered in this cooperative group, Phase I-II dose-escalation trial of three-dimensional conformal radiotherapy for localized carcinoma of the prostate treated to a dose of 78 Gy (Level V). Of these patients, 219 were analyzed for acute and 218 for late toxicity. A minimum of 2 Gy/fraction was prescribed to the planning target volume (PTV). Patients were stratified according to the risk of seminal vesicle invasion as determined by Gleason score and presenting prostate-specific antigen level. Group 1 patients had clinical Stages T1-T2 tumors with a seminal vesicle invasion risk of