[Prognostic factors for estrogen therapy of relapsed prostate cancer after maximal androgen blockade (MAB)]

Advanced prostate cancer responds well to endocrine therapy initially, but soon becomes refractory and has a poor prognosis. We analyzed the prognostic factors of prostate cancer responding well initially to maximal androgen blockade (MAB) but later showing PSA relapse and treated with estrogen.

In prostate cancer patients newly diagnosed from January 1992 to December 2008 at our institution, there were 85 patients in that the PSA level dropped below 10 ng/ml by MAB, but showed PSA relapse thereafter and treated with estrogen. We investigated the relationship between age at diagnosis, clinical stage, pathological differentiation, initial PSA, the value of PSA nadir, duration between diagnosis and initiation of estrogen therapy, duration between PSA failure and initiation of estrogen therapy, the value of PSA at estrogen therapy, PSA doubling time (PSA-DT) at estrogen therapy, PSA response three months after initiation of estrogen therapy, use of diethylstilbestrol diphosphate (DES-P) at the initial stage of therapy, local radiotherapy to prostate, type of estrogen and prognosis after estrogen therapy.

In Kaplan-Meier method, factors which showed poorer prognosis were stage B and D, poorly differentiated, PSA 11.9 ng/ml or higher at estrogen therapy, PSA-DT shorter than 2.3 months before estrogen therapy and PSA response without CR three months after initiation of estrogen therapy. In multivariate analysis, the factor that most significantly affected prognosis after estrogen therapy was PSA response three months after initiation of estrogen therapy (hazard ratio: 12.61), followed by PSA-DT at estrogen therapy (hazard ratio: 2.59).

We investigated the prognostic factors refractory to MAB and treated with estrogen. These results are useful in planning the therapy, and in explaining the status or future prospective of the disease to families and patients.