Long-term impact of conservative management on localized prostate cancer. A twenty-year experience in Japan.

The clinical outcome of 107 patients with localized prostate cancers over the past twenty years was analyzed retrospectively. Immediate endocrine therapy was administered in 55 patients after diagnosis. The other group of 52 patients did not receive any anti-tumor treatment until progression. Overall, 22 patients (21%) died of prostate cancer, while 45 (42%) died of other known causes. During a mean observation period of thirty-seven months, 27 (25%) experienced progression of the disease (local in 9, distant metastasis in 25, and both in 7 patients). The cancer-specific survival rates for these 107 patients were 78 percent at five years and 71 percent at ten years. The timing of endocrine therapy and age at diagnosis did not influence patient's prognosis. Tumor stage failed to demonstrate any prognostic significance after being controlled for other factors including tumor grade. Poorly differentiated histology appeared to be the sole and the strongest predictor for both tumor progression and cancer death. Prostate cancer may not differ significantly among races once it becomes clinically manifest. Expectant management for localized prostate cancer in well and moderately differentiated cancer may be justified because of the higher probability of dying of other intercurrent causes especially in the elderly group of patients. However, definitive forms of therapy should be considered for the group of patients with poorly differentiated tumor who have reasonably long life expectancy.