Neoadjuvant hormone therapy: the Canadian trials

Abstract

The Canadian Urologic Oncology Group has carried out three studies of neoadjuvant hormonal therapy (NHT) in prostate cancer. The first, a study of 3 months of cyproterone acetate (CPA) 100 mg TID in patients undergoing external-beam radiation therapy, showed a benefit with respect to time to biochemical progression. There are no survival or clinical progression data available from this study. The second study involved 3 months of CPA prior to radical prostatectomy compared with radical prostatectomy alone and enrolled 200 patients. The probability of biochemical progression at 36 months was similar in the two groups (CPA 40%; surgery alone 30%; P = 0.3233). More recently, we have carried out a randomized trial of 3 v 8 months of leuprolide plus flutamide prior to radical prostatectomy in 547 patients. Patients were stratified by clinical stage, Gleason grade, and serum prostate specific antigen (PSA) concentration. In the 3- and 8-month groups, presurgery PSA concentrations were <0.1 ng/mL in 35% v 73%, and >0.3 ng/mL in 37% v 10%, respectively. In the 3- and 8-month groups, the positive margin rates were 17% and 5% and the organ-confined rates 71% and 91% (P < 0.01). One-year follow-up is now available on the entire cohort. Data regarding time to biochemical and clinical progression and overall and disease-specific survival will be required to determine whether this change in the pathologic findings translates into a patient benefit.