Clinical efficacy of primary combined androgen blockade for Japanese men with clinically localized prostate cancer unsuitable for local definitive treatment: a single institution experience.

Background: Primary hormonal therapy has been mostly used for patients with advanced prostate cancer, as international guidelines do not recommend its use for patients at earlier disease stages. However, there seems to be a discrepancy between the guideline recommendations and clinical practice on the use of primary androgen deprivation therapy for localized prostate cancer in Japan. Therefore, we retrospectively analyzed a single-institution experience in primary combined androgen blockade (CAB) for localized prostate cancer.
Patients and Methods: The study included 187 patients with T1c-T3a prostate cancer unsuitable for local definitive treatment and treated with primary CAB. Clinical outcomes, predictive factors of PSA relapse and adverse events were investigated.
Results: The progression-free, disease-specific, and overall survival rates of all patients at 5 years were 63.0, 99.4 and 95.9%, respectively. Of the several parameters isolated as predictors of prostate-specific antigen (PSA) progression, nadir PSA level and the percentage of positive biopsy cores (%PBC) remained as independent prognostic factors on multivariate analysis. Toxicities were mild to moderate and well tolerated.
Conclusions: Primary CAB treatment brought initial disease control without relapse in the majority of our selected cases. The %PBC may help predict time to relapse in the pretreatment setting. The results implicate that CAB can be an option as a primary treatment for clinically localized prostate cancer unsuitable for local definitive treatment. To confirm the exact efficacy of primary CAB, these findings should be reviewed in a large cohort of patients with long-term follow-up from various viewpoints, including disease control, toxicities, quality-of-life and medical cost.