Alternative Nonsteroidal Antiandrogen Therapy For Advanced Prostate Cancer That Relapsed After Initial Maximum Androgen Blockade

Main Category: Prostate / Prostate Cancer
Also Included In: Urology / Nephrology;  Cancer / Oncology
Article Date: 17 Aug 2008 - 0:00 PDT

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UroToday.com - In the September, 2008 issue of the Journal of Urology, Dr. Hiroyoshi Suzuki and Japanese collaborators reported that following maximum androgen blockade (MAB) for prostate cancer (CaP), the use of alternative nonsteroidal antiandrogens is effective for treating relapsed disease. A total of 232 CaP patients treated with MAB and disease progression made up the study cohort. Upon disease relapse they were treated with an alternative antiandrogen.

For first-line therapy, 39 men received MAB using flutamide and 193 were treated with MAB using bicalutamide. At the time of CaP progression, the first line antiandrogen was stopped and patients assessed for antiandrogens withdrawal syndrome. Second line antiandrogens were then started. Testosterone was confirmed to be in the castrate level. Standard disease response criteria were used.

All patients achieved castrate levels of testosterone. Mean patient age was 71.5 years and PSA before treatment was 1,047ng/ml. Of the 193 men initially treated with bicalutamide, 143 (74%) achieved a complete response (CR) and all attained a CR or partial response (RP). Of the 39 flutamide treated patients, 32 (82%) achieved a CR and all attained a CR or PR. The duration of the first line MAB response was 452 days and cause-specific survival was significantly improved in the CR patients compared to the non-CR men. Antiandrogen withdrawal response rates were 15.5% for bicalutamide and 12.8% for flutamide. Second line alternative antiandrogen treatment was effective regardless of antiandrogens withdrawal syndrome status.

Second line alternative antiandrogen agents resulted in an overall PSA decrease of 50% or greater in 35.8% and a PSA response of 0 to 50% was noted in 25.4%. There was no difference with regard to response between bicalutamide and flutamide. Seventy of the 83 good responders had response duration of 202 days. More than half of the patients that had started second line therapy at a PSA level <4.0ng/ml showed a better PSA response. Survival in CR men was better than for non-CR patients. Antiandrogen withdrawal response and Gleason score <7 were significant predictors of cause-specific survival. In multivariable analysis, the response to second line therapy was the most important factor in predicting cause-specific survival. Clinical characteristics that predicted the response to second line hormonal manipulation were clinical stage, M category, and the response to first line MAB therapy.

Suzuki H, Okihara K, Miyake H, Fujisawa M, Miyoshi S, Matsumoto T, Fujii M, Takihana Y, Usui T, Matsuda T, Ozono S, Kumon H, Ichikawa T, Miki T
J Urol. 2008 Jul 15. Epub ahead of print.
doi:10.1016/j.juro.2008.05.045

Reported by UroToday.com Contributing Editor Christopher P. Evans, MD, FACS

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