Long-term androgen deprivation therapy improves survival in prostate cancer patients presenting with prostate-specific antigen levels > 20 ng/mL.

Abstract

To assess the benefit of androgen deprivation (AD) and its optimal duration in patients with prostate cancer treated with external beam radiotherapy, who present with prostate-specific antigen levels > 20 ng/mL. A total of 307 patients treated with external beam radiotherapy, AD, and presenting with a PSA level > 20 ng/mL were identified from the Prostate Cancer Outcomes Initiative database of the British Columbia Cancer Agency. Androgen deprivation was defined as short term (ST-AD, < 12 months) or long term (LT-AD, > or = 12 months). The endpoints analyzed were biochemical control (no evidence of disease) (bNED), overall survival, and cause-specific survival. Statistical analysis was conducted with Kaplan-Meier estimates, log-rank tests, and multivariate analyses with logistic and Cox regression models. There were 151 patients in the ST-AD group and 156 in the LT-AD group. The distributions of Gleason score and stage were comparable in the two cohorts. Median follow-up times were 48 months for patients treated with ST-AD and 45 months for patients treated with LT-AD. The median durations of AD were 6 and 25.6 months for the ST-AD and LT-AD groups, respectively. The bNED rate was 37% for the ST-AD group and 62.5% for the LT-AD group (p < 0.0001). The 5-year overall survival rate was 75% in the ST-AD group vs. 87.5% for the LT-AD group (p = 0.0091). The 5-year cause-specific survival rate was 82% for the ST-AD group vs. 94% for the LT-AD group (p = 0.0072). Several randomized trials have demonstrated the benefit of LT-AD in high-risk patients with prostate cancer. In some reports, the survival advantage seems to be restricted to patients with high Gleason score. The present analysis supports the hypothesis that LT-AD improves bNED and survival rates in patients presenting with a PSA level > 20, irrespective of Gleason score or T stage.