Treatment of intermediate-risk prostate cancer with brachytherapy without supplemental pelvic radiotherapy: a review of the H. Lee Moffitt Cancer Center experience

Abstract

Purpose: To determine the biochemical outcomes of patients with intermediate-risk prostate cancer treated at the H. Lee Moffitt Cancer Center with an I-125 permanent seed implant without supplemental pelvic radiotherapy.

Methods and materials: Under an institutional review board approved protocol, the charts of 88 patients with intermediate-risk prostate cancer and a minimum follow-up of 36 months treated with brachytherapy without supplemental pelvic radiotherapy were reviewed. Median follow-up for the whole cohort was 57 months (range 37-121). Biochemical failure was defined using the American Society for Therapeutic Radiology and Oncology definition.

Results: The 5-year biochemical failure-free survival for the cohort was 83%. Patients with perineural invasion had a worse biochemical outcome, which was statistically significant (perineural invasion vs. no perineural invasion, 5-year biochemical failure-free survival 64% vs. 89%, P = 0.004). None of the following factors were found significant in this subset of patients: Gleason scores 6 versus 7, primary Gleason grades 3 versus 4, percentage of core positive <20% versus >20%, number of cores positive <2 versus 2 versus >2, hormonal therapy versus no hormonal therapy, T1 versus T2, prostate-specific antigen <10 versus >10, or > or =2 intermediate risk factors versus 1 intermediate risk factor.

Conclusions: Our data suggest that patients with intermediate-risk prostate cancer may be treated effectively with brachytherapy without supplemental pelvic radiotherapy. However, because of the limited nature of our study, we cannot exclude that patients with intermediate-risk prostate cancer may benefit from supplemental external beam radiotherapy.