Pretreatment prostate-specific antigen doubling times: clinical utility of this predictor of prostate cancer behavior.

PURPOSE

The distribution of pretreatment and posttreatment prostate specific antigen (PSA) doubling times (PSADT) varies widely. This report examines the pretreatment PSADT as an independent predictor of biochemical freedom from disease (bNED) and describes the clinical utility of PSADT.

METHODS AND MATERIALS

Ninety-nine patients with T1-3 NX, M-0 prostate cancer treated between February 1989 and November 1993 have pretreatment PSADTs calculated from three or more PSA levels. Biochemical disease-free (bNED) survival (failure is PSA > or = 1.5 ngm/ml and rising) is evaluated by multivariate analysis of common prognostic indicators and PSADT.

RESULTS

Prostate-specific antigen doubling time (PSADT) is a significant predictor of survival along with radiation dose. Patients with a pretreatment PSADT of < 12 months show 50% failure by 18 months, while those with a PSADT that is not increasing show only 3% failure at 3 years.

CONCLUSIONS

Prostate-specific antigen doubling time (PSADT) is a predictor of bNED outcome in prostate cancer. Patients with PSADT < 12 months have aggressive disease, and should be considered for multimodal therapy. Slow PSADT (> or = 5 years) is observed in 57% of patients, and this end point may be considered in the decision to observe rather than to treat. After treatment failure, the PSADT may be used to determine which patients do not need immediate androgen deprivation.