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

: 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 prostate-specific 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.