Survival outcomes and toxicity in older adults with metastatic castration-resistant prostate cancer (mCRPC) treated with androgen receptor targeted (ART) therapies.

Abstract

117 Background: Prostate cancer (PCa) and especially advanced PCa largely affects older adults with a median age of diagnosis of 67. Despite ART’s role as a mainstay of treatment (tx) in advanced PCa, little is known about its risks/benefits in older adults. We aimed to examine survival outcomes and safety in patients (pts) with mCRPC ≥75 years-old (y.o) on ART. Methods: The records of mCRPC pts treated with ART at the Mount Sinai Hospital between 2010 and 2021 were screened for demographics, medical history, ART course, tx toxicity, and survival outcomes. PSA progression free survival (PFS) between pts ≥75 y.o and pts ≤75 y.o was assessed as the primary outcome. Secondary outcomes were overall survival (os) and tx toxicity. Tx toxicity was evaluated using physician documented tx side-effects (SE)s. Fischer’s exact was used to compare baseline characteristics and tx SEs. Cox proportional hazards models were used to compare survival outcomes. Results: Of 153 pts, 97 were < 75 y.o and 56 were ≥75 y.o. Within the <75 y.o group, 17 (17.5%) were post-chemo compared to 7 (12.5%) in the ≥75 group (p = .493) Relevant baseline characteristics (ECOG ≥2, Race, Gleason 4-5, hospitalizations, and CCI) were not significantly different. Median PSA PFS was 14.2 (≥75 y.o) and 17.3 months (<75 y.o) with no significant difference on univariate or multivariate analysis (HR: 1.1 [0.69, 1.74;] p = 0.697. Median OS was 32.4 months for the ≥75 y.o cohort and 32.3 months for the <75 y.o cohort (HR: 1.38 [0.88, 2.17;] p = 0.156). The 5 most common SEs by group are reported below. Of note, adults ≥75 y.o were more likely to report edema compared to the <75 y.o pts (8.2% vs 21.4%, p-value = .026). Conclusions: Pts ≥75 on ART experienced similar survival benefits compared with pts <75. While older adults were more likely to report edema, overall tx toxicity profiles did not differ significantly. Ultimately, these findings ground evidence-based counseling and tx for older adults with mCRPC considering ART. [Table: see text]