Impact of PSA nadir, PSA response and time to PSA nadir on overall survival in real‐world setting of metastatic hormone‐sensitive prostate cancer patients

Abstract

AbstractBackgroundTo evaluate the impact of prostate‐specific antigen (PSA) nadir, PSA response and time to PSA nadir (TTN) in metastatic hormone‐sensitive prostate cancer (mHSPC) patients on overall survival (OS) in the era of combination therapies.MethodsDifferent PSA nadir cut‐offs (including ultra‐low PSA) were tested for OS analyses. Additionally, PSA response ≥99% was evaluated, as well as TTN categorized as <3 versus 3–6 versus 6–12 versus >12 months. Multivariable Cox regression models predicted the value of PSA nadir cut‐offs, PSA response and TTN on OS. Sensitivity analyses were performed in de novo and high volume mHSPC patients.ResultsOf 238 eligible patients, PSA cut‐offs of <0.2 versus 0.2–4.0 versus >4.0 ng/mL differed significantly regarding median OS (96 vs. 56 vs. 44 months, p < 0.01), as well as in subgroup analyses of de novo mHSPC patients and multivariable Cox regression models. A more stringent PSA cut‐off of <0.02 versus 0.02–0.2 versus >0.2 ng/mL also yielded significant median OS differences (not reached vs. 96 vs. 50 months, p < 0.01), even after additional multivariable adjustment. A PSA response ≥99% was also significantly associated with better OS than counterparty with <99% response, even after multivariable adjustment (both p < 0.02). When TTN groups were compared, patients with longer TTN harbored more extended OS than those with short TTN (<3 vs. 3–6 vs. 6–12 vs. >12 months: 34 vs. 50 vs. 67 vs. 96 months, p < 0.01). Virtually similar results were observed in sensitivity analyses for high volume mHSPC patients.ConclusionsIn times of combination therapies for mHSPC, a PSA nadir of respectively, <0.2 and <0.02 ng/mL are associated with best OS rates. Moreover, a relative PSA response ≥99% and a longer TTN are clinical important proxies for favorable OS estimates.