Purpose: Whether pretreatment factors that predict for time to prostate specific antigen (PSA) failure also predict for time to prostate cancer specific death after PSA failure for patients with competing causes of mortality treated during the PSA era was the subject of this study.
Materials and methods: Of 415 men with a median age of 73 years who underwent external beam radiation therapy between 1988 and 2001 for clinically localized prostate cancer 160 (39%) experienced PSA failure and 96 (23%) died. In 46 men (48%) the cause of death was prostate cancer. Cox regression multivariable analyses (multivariable analysis) were performed to evaluate the ability of the pretreatment PSA and centrally reviewed biopsy Gleason score to predict time to prostate cancer specific death after PSA failure.
Results: When analyzed as categorical variables using multivariable analysis, biopsy Gleason score 4 + 3 (p = 0.02), 8 to 10 (p = 0.02) disease and a pretreatment PSA greater than 20 ng./ml. (p = 0.03) were significant predictors of time to prostate cancer specific death after PSA failure. Estimates of prostate cancer specific death 5 years after PSA failure were 24%, 40% and 59% (p = 0.01) for patients with a biopsy Gleason score < or = 6, 3 + 4, 4 + 3 or higher and 22%, 40% and 60% (p = 0.04) for patients with a pretreatment PSA of 10 or less, greater than 10 and 20 or less, or greater than 20 ng./ml., respectively.
Conclusions: Patients at high risk for PSA failure after radiation therapy based on pretreatment PSA greater than 20 ng./ml. or biopsy Gleason score 4 + 3 or greater are also at high risk for death from prostate cancer after PSA failure despite competing causes of mortality.