Combined Androgen Blockade with Nonsteroidal Antiandrogens for Advanced Prostate Cancer: A Systematic Review

Reviewers: Li Liu, MD
Source: Urology, Vol 57, 2001: 727-732

Introduction

In metastatic prostate cancer the main systemic treatment is androgen suppression (AS), either by surgical castration (orchiectomy) or by long-term use of a luteinizing-hormone-releasing-hormone agonist. The low plasma concentrations of androgens that remain, which are chiefly of adrenal origin, could be further reduced by addition of long-term treatment with nonsteroidal antiandrogen such as nilutamide, flutamide, or cyproterone acetate. Such combination of AS with an antiandrogen is referred to as total androgen blockade (TAB). There have been many randomized trials comparing TAB with AS alone but, on average, they involved only a few hundred patients each. In this meta-analysis, the researchers reviewed the mortality and morbidity findings from all the available trials of TAB versus AS in advanced prostate cancer.

Method

A total of 20 trials of 6320 patients that included a randomization of immediate nonsteroidal antiandrogens with castration (TAB) versus castration alone (AS) for metastatic prostate cancer were included.

Results

• The 5-year overall survival was 30.1% for TAB group and 24.9% for AS only group with an odd radio of 1.29.
• The 5-year cancer-specific survival was significantly better in the TAB group than the AS group with odd ratio of 1.58 demonstrated in 2 studies.
• The TAB group experienced more complications, including diarrhea, gastrointestinal pain, and nonspecific ophthalmologic events.

Discussion

In metastatic prostate cancer, addition of a nonsteroidal antiandrogen to castration only improved the 5-year survival by about 5%. Although this overview brought together all available randomized evidence on survival, it did not assess other medical outcomes, quality of life, or treatment costs. Longer follow-up is needed to draw any definitive conclusions.