Actuarial disease-free survival after prostate cancer brachytherapy using interactive techniques with biplane ultrasound and fluoroscopic guidance

Purpose: To evaluate the effectiveness and safety of interactive transperineal brachytherapy under biplane ultrasound and fluoroscopic guidance in patients with localized prostate cancer. Methods and Materials: Brachytherapy using ¹²⁵I or ¹⁰³Pd radioactive seeds either alone or in combination with adjunctive external beam radiotherapy (XRT) was administered to 490 patients at a single institution. Post-treatment follow-up included clinical assessment of disease status, assays of serum prostate-specific antigen (PSA) levels and documentation of treatment-related symptoms and complications. Results: Actuarial disease-free survival at 5 yr was 79% (95% CI, 71-85%), and the 5-yr actuarial rate of local control was 98% (95% CI, 94-99%). Post-treatment PSA nadir and pretreatment PSA level were found to be significant predictors of disease-free survival. In patients with a PSA nadir < 0.5 ng/ml, 5-yr disease-free survival was 93% (95% CI, 84-97%), compared with 25% (95% CI, 5-53%) in patients whose PSA nadir was 0.5-1.0 ng/ml and 15% (95% CI, 3-38) in patients with a PSA nadir > 1.0 ng/ml. Brachytherapy was well tolerated with few post-treatment complications. Conclusion: A broad range of patients with localized prostate cancer can benefit from transperineal brachytherapy with minimal morbidity. A post-treatment PSA nadir below 0.5 ng/ml provides a useful prognostic indicator of favorable long-term outcome.