Preliminary results of bicalutamide monotherapy on biochemical failure of localized prostate cancer

Objectives: To prospectively assess the efficacy and tolerability of bicalutamide monotherapy on biochemical failure of localized prostate cancer following total androgen deprivation (TAD) and 3D-conformal radiotherapy (3D-CRT). Methods: Between January 1998 and January 2002, we prospectively evaluated 20 eligible patients with biochemical failure. All patients were initially treated with neoadjuvant TAD of 12 weeks before 3D-CRT (73.6 Gy at isocenter) and same regimen of TAD after completion of radiotherapy for 24 weeks in high-risk patients. We prescribed 150 mg/day bicalutamide monotherapy for 24 weeks in patients with biochemical failure according to American Society for Therapeutic Radiology and Oncology 1997 consensus definition. Primary end points were biochemical control (BC) and metastasis-free survival (MFS). Results: Median follow-up was 28 months after biochemical failure date. At last visit, the median PSA level of all patients was 2.80 ng/dl while 1.28 ng/dl for nonmetastatic and 30.7 ng/dl for metastatic patients. BC was successfully obtained in five of them with only bicalutamide. Ten patients developed distant metastasis among 15 patients receiving salvage TAD. MFS was 55% at three years for all 20 patients. Temporary gynecomasty was observed in 11 patients as the only serious toxicity. Conclusions: Bicalutamide monotherapy seems to be a tolerable regimen for patients with biochemical failure following 3D-CRT, and TAD and may be effective in patients with low PSA levels at biochemical failure.