Background and purpose: The ongoing Early Prostate Cancer (EPC) programme is assessing bicalutamide ('Casodex') 150 mg, either alone or as adjuvant to treatment of curative intent, in patients with localised or locally advanced prostate cancer (n=8113). This paper presents an exploratory analysis of the subgroup of the EPC programme who received radiotherapy with curative intent (n=1370) in order to determine the efficacy (in terms of progression-free survival [PFS]) and tolerability of bicalutamide 150 mg in this setting.
Patients and methods: 1370 patients with T1-4, MO, any N prostate cancer received bicalutamide 150 mg or placebo adjuvant to radiotherapy of curative intent. This analysis was undertaken at median 5.3 years' follow-up.
Results: In patients with locally advanced disease (n=305), bicalutamide adjuvant to radiotherapy significantly increased PFS by 53% (event-time ratio 1.53; 95% confidence intervals [CI] 1.16, 2.02) compared with placebo and reduced the risk of disease progression by 42% (hazard ration [HR] 0.58; 95% CI 0.41, 0.84; P=0.00348). In these patients, objective progression was experienced by 33.5% of those randomised to bicalutamide versus 48.6% for those randomised to placebo. The between-group difference in patients with localised disease (n=1065) failed to reach statistical significance (HR 0.80; 95% CI 0.62, 1.03; P=0.088). The most common adverse events were breast pain (74.8%) and gynaecomastia (66.6%), which were mild to moderate in >90% of cases.
Conclusions: Bicalutamide 150 mg/day given as adjuvant to radiotherapy significantly improved PFS in patients with locally advanced prostate cancer. For patients with localised disease, the results at this stage from the radiotherapy subgroup and the overall EPC programme suggest that adjuvant hormonal therapy is currently not appropriate. There were no unexpected tolerability findings.