Objectives: Men with metastatic hormone-refractory prostate cancer (HRPC) form a heterogeneous population with a wide range of symptoms and variable survival. Patient selection is critical in determining which patients will receive the most benefit from aggressive chemotherapy. The prostate-specific antigen (PSA) doubling time (PSADT) has been shown to be a surrogate for survival in earlier stages of prostate cancer, but its utility as a predictor in HRPC is unknown.
Methods: A retrospective chart review of 224 patients with HRPC treated from 1998 to 2002 was performed. Eligible patients had HRPC and evidence of metastatic disease. The PSADT at HRPC diagnosis was calculated, and the optimal PSADT stratification was obtained using the log-rank chi-square statistic. Kaplan-Meier curves were used to estimate overall survival between the groups.
Results: During the follow-up period, 80% of patients died, 93% of prostate cancer. Overall, the median survival from diagnosis of HRPC was 15.1 months (range 0.5 to 90.5). The optimal PSADT stratification for survival was 70 days. Patients with a PSADT of 70 days or less survived 11 months compared with 19 months for those with a PSADT of more than 70 days [relative risk (RR) 1.79, P <0.0001].
Conclusions: PSADT serves as an independent prognostic marker for survival in patients with metastatic HRPC. Men with a PSADT of 70 days or less had a significantly shorter survival time compared with men with a PSADT of more than 70 days. Inclusion of PSADT with other clinical data could help clinicians select men at high risk of early mortality who may most benefit from aggressive treatment regimens, such as docetaxel-based regimens.