Changes in levels of prostate-specific antigen and testosterone following discontinuation of long-term hormone therapy for non-metastatic prostate cancer

Introduction : We evaluated changes in levels of prostate-specific antigen (PSA) and testosterone following discontinuation of long-term hormone therapy for non-metastatic prostate cancer. Patients and Methods : Treatment was discontinued in 31 patients
with non-metastatic prostate cancer (clinical stage B-C) after≧5 years of hormone therapy, during which time PSA level had been maintained less than 0.5 ng/ml. PSA and testosterone levels were measured after discontinuation of therapy. PSA>4.0 ng/ml was defined as PSA relapse in this study. Results : Mean age at discontinuation of hormone therapy was 78.7 years (range, 66-90). Mean duration of follow-up after discontinuation of therapy was 25.5 months. PSA non-relapse rate was quite high (87.1%). 4 of the 31 patients showed PSA relapse, after 12-24 months. Testosterone level exceeded castration level (<1.0 ng/ml) in 3 patients, each of whom developed PSA relapse. Conclusions : During follow-up, the PSA relapse rate was relatively low. These results suggest that treatment may be safely discontinued in many prostate cancer patients. In addition, rate of testosterone recovery after treatment discontinuation may be associated with PSA relapse. When considered the adaptation of discontinued, or intermittent hormone therapy for aged people, these findings may be useful.