Purpose: Prostate cancer is generally controlled by endocrine therapy even in an advanced state, but relapse may occur in many cases. Generally, the prognosis of a relapsed case is poor, but the prognosis differs case by case. We experienced 74 cases of prostate cancer relapsed after effective endocrine therapy, and investigated the relationship between the PSA-related parameters, clinical stage and prognosis.
Patients and methods: We investigated 74 prostate cancer patients whose PSA declined 10 ng/ml or lower by the treatment consisting of endocrine therapy, but relapsed later. Pre-treatment PSA, the value of PSA nadir, the period from the start of treatment to PSA nadir, the period from the start of treatment to relapse, PSA doubling time (PSA-DT) at relapse and PSA response to the second line therapy at relapse were calculated, and compared with the clinical stage and prognosis. The relationship between each PSA parameter and clinical stage was tested using the Kruskal-Wallis test and chi 2 test. Cancer-specific survival after relapse in stage D patients was calculated by the Kaplan-Meier method and differences in prognosis were tested using the Logrank test.
Results: Pre-treatment PSA was significantly (p < 0.01) high, while the period from the start of treatment to relapse (p < 0.05) and PSA-DT at relapse (p < 0.01) was significantly short as the stage progressed. According to PSA response to the second line therapy at relapse, the rate of CR + PR was significantly (p < 0.05) high in clinical stage B + C group compared to clinical stage D group. The prognosis after relapse was significantly poorer in patients with relapse within 10 months after start of treatment than in those with relapse later, and in patients whose PSA-DT at relapse was shorter than 2 months than in those with a longer PSA-DT.
Conclusions: The period from the start of treatment to relapse, and PSA-DT at relapse were useful PSA-related parameters for predicting prognosis after relapse, and for determining the strategy of cancer therapy after relapse. Using these data, the physician can inform the family and the patient of the prognosis more accurately, so that they can adjust future plans.