Long-term survival of extremely advanced prostate cancer patients diagnosed with prostate-specific antigen over 500 ng/ml

Objective: To investigate survival of hormone-naïve prostate cancer patients diagnosed with prostate-specific antigen ≥500 ng/ml, stratified according to the prostate-specific antigen level and type of therapy. Methods: Data of prostate cancer patients with prostate-specific antigen ≥500 ng/ml diagnosed between 2001 and 2003 and receiving primary androgen deprivation therapy were extracted from the Japan Study Group of Prostate Cancer database. Cancer-specific survival and overall survival were assessed according to the prostate-specific antigen level (500-999, 1000-4999 and ≥5000 ng/ml) and type of therapy using Kaplan-Meier analyses and multivariate Cox proportional hazards models including age, Gleason score, oncological stage and comorbidity. Results: The median follow-up was 27 months (interquartile range, 13-51) and a total of 1961 patients were included. Five-year cancer-specific and overall mortalities were 39.0 and 33.0%, respectively. There was a significant inverse relationship between overall survival and prostatespecific antigen magnitude among combination therapy patients, but not monotherapy patients (log-rank test, P = 0.034 and 0.558, respectively). The median overall survival in combination therapy patients with low-, intermediate- and high prostate-specific antigen and monotherapy patients with any prostate-specific antigen were 79, 59, 45 and 43 months, respectively. Multivariate analysis showed that combination therapy in patients with low- and intermediate prostate-specific antigen was significantly associated with a favorable overall survival compared with monotherapy (hazard ratios 0.66 and 0.75, respectively, both P < 0.001). Similar results were obtained for cancer-specific survival. Conclusions: There are major survival differences in extremely high prostate-specific antigen cases according to the prostate-specific antigen level and hormone therapy type and those patients would benefit notably from combination androgen blockade.