Correlation of baseline serum testosterone (T) and serum prostate-specific antigen (PSA) at 7 months (7 mo PSA) in patients (pts) with new hormone sensitive metastatic prostate cancer (mHSPC) treated with continuous androgen deprivation therapy (cADT).

Abstract

231 Background: Based on data from > 1,000 men with new mHSPC undergoing ADT in the SWOG-9346 study, a failure to achieve a 7 mo PSA of ≤4 ng/mL, is a powerful negative predictor of survival (Hussain et al., JCO 2006). Following baseline clinical variables predicted lack of achieving 7 mo PSA ≤ 4.0 ng/mL: increased age, PSA, and bone pain, poor performance status, and Gleason sum ≥ 8. We hypothesized that the baseline serum T is also an independent predictor of 7 mo PSA. Methods: Eligible pts were identified from an institutional database. The association of baseline clinical and disease characteristics with 7 mo PSA were analyzed using multivariate regression model (Table). Results: 54 pts were eligible for inclusion. 44% achieved undetectable 7 mo PSA, and 25% had a 7 mo PSA ≥ 4 ng/mL suggesting a representative population, similar to that in the SWOG-9346 study. Significant association between covariates and 7 mo PSA was observed (Prob > F = 0.0107; R2 = 0.404). Baseline serum T and PSA were independent predictors of 7 mo PSA. Baseline serum T, as a continuous variable, showed negative correlation with 7 mo PSA, while baseline PSA showed a positive correlation (Table). Conclusions: Baseline serum T independently predicts 7 mo PSA. Pts with new mHSPC with lower baseline T may have improved outcomes with deeper androgen blockade with ADT along with a 17,20-lyase and 17-alpha-hydroxylase inhibitor or a second generation androgen receptor inhibitor at the time of induction. Data need further validation in a larger cohort. [Table: see text]