Key clinical point: Posttreatment free prostate-specific antigen ratio (FPSAR) of 0.10 or greater is associated with more aggressive disease in patients with prostate cancer treated with either radical prostatectomy (RP) or radiotherapy (RT), suggesting a potentially novel role for this biomarker.

Major finding: A FPSAR of less than 0.10 resulted in longer metastasis-free-survival (14.8 vs. 9.3 years and 14.8 vs. 13 years, respectively) and castrate-resistant prostate cancer-free (CRPC) survival (median, not reached vs. 9.9 years and 20.7 vs. 13.8 years, respectively) in the RP and RT cohorts. A FPSAR of 0.10 or greater was associated with increased metastasis in the RP cohort (hazard ratio [HR], 1.915; P = .003) and RT cohort (HR, 1.754; P = .016) and increased CRPC in the RP cohort (HR, 2.470; P less than .001).

Study details: This single-center retrospective cohort study included patients with a FPSAR after RP or RT (total n=822; 305 RP-treated, 363 RT-treated, 154 biobank).

Disclosures: The study did not receive any funding. The authors declared no conflicts of interest.