Prognostic Factors in Patients with Prostate Cancer Refractory to Endocrine Therapy: Univariate and Multivariate Analyses Including Doubling Times of Prostate-specific Antigen and Prostatic Acid Phosphatase

Abstract

Although several prognostic factors have been discussed, multivariate analysis that includes tumor marker doubling time has not yet been examined in patients with prostate cancer refractory to endocrine therapy. A number of conventional prognostic factors including doubling times of prostate-specific antigen and/or prostatic acid phosphatase were examined in 56 prostate cancer patients who were refractory to endocrine therapy, using univariate and multivariate analyses. On univariate analysis, 6 parameters (doubling times of prostate-specific antigen and prostatic acid phosphatase at the time of refractory status, performance status, duration from beginning of endocrine therapy to prostatespecific antigen/prostatic acid phosphatase failure, mode of recurrence, the presence or absence of prostate-specific antigen/prostatic acid phosphatase normalization, and alkaline phosphatase) were shown to be significant prognostic factors. On multivariate analysis, only performance status and doubling times of prostate-specific antigen and prostatic acid phosphatase were significant. These observations showed that the doubling times of prostate-specific antigen and prostatic acid phosphatase, calculated at the time of prostate-specific antigen/prostatic acid phosphatase failure by estimating serial prostate-specific antigen or prostatic acid phosphatase, were a valuable prognostic factor in patients with prostate cancer refractory to endocrine therapy.