Salvage prostate brachytherapy for localized prostate cancer failure after external beam radiation therapy

Abstract

Purpose: To determine the toxicity and clinical outcome of salvage prostate brachytherapy for localized prostate cancer failure after external beam radiation therapy.

Methods and materials: Twenty-one patients underwent (103)Pd salvage brachytherapy (median minimum peripheral dose, 90Gy) after local failure after external beam radiation (median dose, 66.6Gy) from 1/21/1998 to 4/5/2005. The median age was 72 years. Six patients had prior transurethral resection of the prostate. The median Gleason score was 7 and the median preimplant prostate-specific antigen was 3.8. Twelve patients received concurrent androgen ablation with prostate brachytherapy. Biochemical failure was defined as three consecutive rises in prostate-specific antigen scored at the call date, initiation of hormone therapy, or clinical failure. Toxicity was defined according to the National Cancer Institute common toxicity criteria and the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late radiation morbidity scoring scheme.

Results: With a median followup of 36 months, the actuarial 3-year and 5-year overall survival rates were 81% and 81%, and the biochemical failure-free survival rates were 94% and 38%, respectively. There was no significant difference in biochemical failure-free survival (p=0.98) and overall survival (p=0.13) for patients who had androgen ablation. Four patients developed biochemical failure and 1 patient developed distant metastasis at 59 months from treatment. Four patients had Grade 2 genitourinary adverse events, 2 patients had Grade 1 genitourinary adverse events, and 1 patient had a Grade 2 gastrointestinal adverse event. There were no Grade 3 or higher adverse events. All three deaths were secondary to other medical comorbidities.

Conclusions: Salvage prostate brachytherapy after external beam radiation failure can be safely performed with acceptable biochemical control. This treatment option should be considered for patients who have prolonged life expectancy after localized external beam radiation failure.