Bicalutamide (150 mg) versus placebo as immediate therapy alone or as adjuvant to therapy with curative intent for early nonmetastatic prostate cancer: 5.3-year median followup from the Scandinavian Prostate Cancer Group Study Number 6

Abstract

Purpose: We evaluated the benefits of adding 150 mg bicalutamide to standard care, that is radical prostatectomy, radiotherapy or watchful waiting (WW), in patients with localized or locally advanced prostate cancer.

Materials and methods: A total of 1,218 men with T1-4, M0, any N prostate cancer were recruited from 62 Scandinavian centers and randomized 1:1 to 150 mg bicalutamide or placebo plus standard care. Primary end points were progression-free survival (PFS) and overall survival.

Results: At a median 5.3-year followup patients with locally advanced disease had improved survival with bicalutamide (HR 0.68, 95% CI 0.50 to 0.92), while those with localized disease had decreased survival with bicalutamide (HR 1.47, 95% CI 1.06 to 2.03). Bicalutamide significantly improved PFS, decreasing the risk of disease progression by 43% compared with placebo (HR 0.57, 95% CI 0.48 to 0.68, p<0.0001). The rate of events was 35.4% for bicalutamide and 46.2% for placebo. Patients with locally advanced disease gained the greatest PFS benefits with bicalutamide (HR 0.40, 95% CI 0.31 to 0.52). Since 81% of the trial population were untreated before entry and would otherwise have undergone WW, the findings essentially reflect the results of immediate hormone therapy vs WW.

Conclusions: Bicalutamide (150 mg) provides significant benefit in patients with locally advanced disease. In previously untreated patients there may be a tumor burden below which endocrine therapy provides no benefit or may even decrease survival.