Urethral toxicity vs. cancer control--lessons to be learned from high-dose rate brachytherapy combined with intensity-modulated radiation therapy in intermediate- and high-risk prostate cancer

Abstract

Purpose: To describe biochemical relapse-free survival (BRFS) and late toxicity after combined high-dose rate brachytherapy (HDR-B) and intensity-modulated radiation therapy (IMRT) in intermediate- and high-risk prostate cancer patients.

Methods and materials: From March 2003 to September 2005, 64 men were treated by 3×7Gy HDR-B using one implant followed by 50Gy IMRT. Median age was 66.1 years; risk of recurrence was intermediate in 30 (47%) or high in 34 (53%) patients. Forty-four (69%) patients received hormonal therapy. Patients were treated with a median of 13 HDR-B applicators (range, 8-17). Biochemical relapse was defined according to Phoenix criteria. Toxicity was scored according to the Common Toxicity Criteria scale version 3.0.

Results: Median followup was 5.1 years. The 3-year BRFS was 100% and 91% for intermediate- and high-risk patients. Late Grade 2 gastrointestinal (GI) toxicity occurred in 3 (4.7%) patients, late Grade 3 GI toxicity was absent. Late Grade 3 and 4 genitourinary (GU) toxicity was observed in 7 (10.9%) and 2 (3.1%) patients. The 5-year Grade 3 or higher late GU toxicity-free survival was associated with a higher number of HDR-B applicators (p=0.049).

Conclusions: The 3-year BRFS was excellent and late GI toxicity was negligible. However, the late Grade 3 and 4 GU toxicity was unacceptably high.