Cancer control after low-dose-rate prostate brachytherapy performed by a multidisciplinary team with no previous prostate brachytherapy experience

Abstract

Objectives To describe the biochemical disease-free survival observed in the first cohort men treated by a multidisciplinary team of clinicians with no previous experience in low-dose-rate prostate brachytherapy (LDRPB). Methods The information in this report concerns the first 63 men treated with LDRPB alone at our institution between September 1997 and September 1998. All men had histologically confirmed, clinically localized prostate cancer. All men were treated with iodine 125 according to published methods. The prescription dose was 144 Gy according to the Task Group 43 formalism. LDRPB was performed jointly by a radiation oncologist and urologist. Three definitions of biochemical recurrence were used: the American Society for Therapeutic Radiology and Oncology consensus definition; prostate-specific antigen level greater than 0.4 ng/mL at last follow-up; and prostate-specific antigen level greater than 0.2 ng/mL at last follow-up. Biochemical relapse-free survival was estimated using the product-limit method. Putative covariates for biochemical relapse-free survival were examined using the proportional hazards regression model. All P values are two-sided. Results The median follow-up for the entire cohort was 62 months. Of the 63 men, 45 (71%) had more than 60 months of follow-up. The median pretreatment prostate-specific antigen level was 6.68 ng/mL (range 1.1 to 23), and most men (44 of 63; 70%) had nonpalpable disease. The institutionally assigned Gleason score was less than 7 in 54 men (86%). Nine men developed evidence of biochemical relapse at a median of 19 months (range 6 to 38). The 5-year estimate of biochemical relapse-free survival was 85% (95% confidence interval 80% to 90%), 80% (95% confidence interval 74% to 86%), and 70% (95% confidence interval 64% to 76%) according to the three definitions given above. Conclusions The biochemical results achieved in the first cohort of men treated with LDRPB by a previously inexperienced multidisciplinary team of clinicians are similar to the results reported from centers with extensive LDRPB experience.