[Determination of tumor marker doubling time in the patients with prostate cancer relapsed from endocrine therapy].

Twenty seven patients with endocrine therapy relapsed prostate cancer were studied by measuring their prostatic acid phosphatase (PAP), prostate specific antigen (PSA), gamma-semino-protein (gamma-Sm) and alkaline phosphatase (ALP) serially before change of the treatment, and tumor marker doubling time was calculated. The exponential increase in PAP, PSA and gamma-Sm was observed in all patients and ALP showed a similar pattern in some. The values of PAP doubling time were the same as those of PSA, but gamma-Sm doubling time was slightly longer than the former ones. Tumor marker doubling time correlated with survival after the increase in markers, and also with time between the start of endocrine therapy and the increase in markers. Patients who showed either NC or PR to chemotherapy had a longer tumor marker doubling time than those with PD. In cases showing progression of bone metastasis, patients with exponential increase in ALP showed worse prognosis when compared with those showing other patterns. From these results, it was demonstrated that determination of tumor marker doubling time in patients with endocrine therapy relapsed prostate cancer was a valuable method to measure rate of regrowth, and to assess the prognosis after relapse.