Prognostic significance of tissue prostate-specific antigen in endocrine-treated prostate carcinomas

Fine-needle aspiration biopsy is a minimally invasive technique for obtaining sample material suitable not only for cytological grading but also for flow cytometry and for biochemical analyses. The prognostic value of tissue prostate-specific antigen (T-PSA) from fine-needle aspiration biopsies was compared with serum total and free prostate-specific antigen, the ratio of free:total serum prostate-specific antigen, tumor stage, cytological grade, and DNA ploidy in 179 patients with stage T2-T4 prostate cancer (CAP). The patients, who were free from bone metastases at the time of diagnosis, were treated by either orchidectomy or medical castration with GnRH analogues or high-dose parenteral depot estrogens. They were followed for at least for 71 months or until death, and the different variables were correlated to time to progression and time to death from CAP. Using Cox univariate analysis, T-PSA was shown to be the most important factor in predicting time to progression and time to death. When the patients were divided into three groups with respect to T-PSA, 56 of 60 (93%) of the patients with low T-PSA levels developed progressive disease, and 52 of 60 (87%) died of CAP. For patients with intermediate T-PSA levels, the corresponding figures were 9 of 60 (15%) and 6 of 60 (10%). None of the 59 patients with high T-PSA values developed progressive disease. Similar but less pronounced relationships were found between tumor progress and CAP-specific death on the one hand and clinical stage, cytological grade, and DNA ploidy on the other. In a Cox multivariate stepwise analysis, T-PSA was the only important factor for time to progression and death. This was also true for the subgroup of patients with stages T2 and T3 disease only. The study shows that T-PSA is superior to other hitherto routinely used markers for the prediction of outcome of hormone-treated patients with newly diagnosed CAP.