Long-Term Outcome and Toxicity of Salvage Brachytherapy for Local Failure After Initial Radiotherapy for Prostate Cancer

Purpose

To describe long-term outcomes and toxicity after salvage brachytherapy (BT) for local failure after initial radiotherapy for prostate cancer.

Methods and Materials

Between 1994 and 2008, 37 men with local failure after initial prostate radiotherapy (32 external-beam radiation therapy [EBRT] and 5 BT) underwent salvage BT with ¹⁰³Pd or ¹²⁵I. Estimates of freedom from biochemical failure (FFbF, Phoenix definition) and cause-specific survival (CSS) were calculated using the Kaplan-Meier method. Toxicities were graded using CTCv3.0.

Results

Median follow-up was 86 months (range, 2–156). The median dose to 90% of the prostate volume was 122 Gy (range, 67–166). The 10-year FFbF and CSS were 54% and 96%, respectively. On univariate analysis, prostate-specific antigen (PSA) >10 ng/mL at initial diagnosis was significantly associated with FFbF (p = 0.01), and there were trends for both age <70 years (p = 0.08) and PSA <6 ng/mL (p = 0.08) at the time of salvage BT. On multivariate analysis, only presalvage PSA <6 ng/mL (p = 0.046) was significantly associated with improved FFbF. There were three Grade 3 toxicities and one Grade 4 toxicity. Pelvic lymph node dissection before salvage BT was the only variable significantly associated with Grade ≥2 toxicity (p = 0.03).

Conclusion

With a median follow-up of 86 months, salvage prostate BT was associated with a 10-year FFbF of 54% and CSS of 96%. Improved FFbF was associated with a presalvage PSA <6 ng/mL. Toxicity was worse in patients who had undergone pelvic lymph node dissection before salvage BT. Careful patient selection for salvage BT may result in improved outcomes and reduced toxicity.

Prostate cancer, Brachytherapy, Salvage therapy