Absolute Prostate-Specific Antigen Value After Androgen Deprivation Is A Strong Independent Predictor Of Survival In New Metastatic Prostate Cancer

UroToday.com - According to an interim report of SWOG 9346 that appears in the August 20, 2006 issue of the Journal of Clinical Oncology, in men with metastatic prostate cancer (CaP) a PSA level <4ng/ml is strongly predictive of survival after 7 months of androgen deprivation therapy (CaP).

SWOG 9346 is an ongoing prospective intergroup study that randomizes men with metastatic CaP to continuous ADT or intermittent ADT. All participants are initially treated with 7 months ADT and at 7 months, if the PSA is > 4ng/ml they come off study and are treated with continuous ADT. If the PSA is <4ng/ml, then they are randomized to either continuous or intermittent ADT. The accrual goal is 1,512 patients, and at this report 1,395 were registered and 1,345 were eligible for survival analyses. While the study’s primary endpoint is survival, this interim report sought to establish whether an absolute PSA value after ADT is prognostic in metastatic CaP.

Of the 1,395 eligible patients, 1,134 achieved a PSA of <4.0ng/ml during the 7-month induction period and 105 men experienced PSA progression. An undetectable PSA (<0.2ng/ml) was achieved in 675 patients (48%). Predictors for failing to achieve a PSA level of <4.0ng/ml during the induction phase include younger age (10% lower odds for every 5 year increase), higher pre-study PSA (5% increased odds for every 50-unit increase in PSA), worse performance status, bone pain, weight change, higher Gleason score (>8), presence of visceral metastases and distant lymphadenopathy.

Median overall survival was 13 months for the 383 men with a PSA of >4ng/ml at the end of induction, 44 months for the 360 men who had a PSA 0.2-4.0ng/ml, and 75 months for the 602 men with undetectable PSA at 7 months. Patients with a PSA of 4ng/ml or less during the induction had one quarter the risk of dying relative to those who did not have a PSA of <4ng/ml. An undetectable PSA was also a significant predictor of longer survival.

This important report demonstrates that a PSA of 4ng/ml or less and undetectable PSA at the end of a 7-month ADT period is the most powerful predictor of risk of death in patients with CaP metastatic to bone.

Maha Hussain, Catherine M. Tangen, Celestia Higano, Paul F. Schelhammer, James Faulkner, E. David Crawford, George Wilding, Atif Akdas, Eric J. Small, Bryan Donnelly, Gary MacVicar, and Derek Raghavan

J Clin Oncol 2006;224:3984-90
Reviewed by UroToday.com Contributing Editor Christopher P. Evans, M.D.

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