Abstract

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Background: MPM is a rare malignancy, with roughly 300 new cases in the United States annually. CRS-HIPEC has evolved as an important treatment nodality with demonstrated survival benefit. We studied the outcomes of MPM with CRS-HIPEC at a single institution. Methods: We studied a retrospective cohort of patients with malignant peritoneal mesothelioma who underwent CRS–HIPEC at Roswell Park from 2001 to 2023. Overall survival (OS) and progression-free survival (PFS) were estimated from diagnosis to describe the cohort, with one- and five-year rates calculated. Associations between HIPEC agent and OS/PFS were tested using Cox proportional hazards models with time 0 at CRS-HIPEC. Models adjusted for baseline characteristics, including age (y), sex, synchronous cancer, normal platelet count, prior therapy, completeness of cytoreduction (CC≤1), and time from diagnosis to CRS–HIPEC. Results: Thirty-nine patients were included (16 men, 23 women). Median age at diagnosis was 59y (19–79) with women being slightly younger (58 vs 62.5y). Among females, 6 were diagnosed at age < 50y, 9 underwent hysterectomy/salpingectomy/oophorectomy during work-up/management of MPM prior to CRS-HIPEC, occasionally with synchronous endometrial ca (2) or endometriosis (2) and 1 patient was diagnosed as part of infertility workup. Genomic testing was available for 9 cases (HER2 overexpression, alterations in BAP1, TP53, TERT, SETD2). Twenty-seven received mitomycin C and 12 received carboplatin. Three patients underwent repeat CRS–HIPEC. Baseline features were similar except for CC≤1. CC ≤ 1 was attained in 21 patients, not achieved in 11 patients and unknown in 7 patients. Synchronous cancer occurred in 8 patients. Histology was epithelioid in 23, unspecified in 8, Well-differentiated papillary in 5, biphasic in 2, and multicystic in 1. Twelve received prior therapy in the form of systemic therapy (8) or CRS without HIPEC (4). Median OS (from diagnosis) was not reached. 1- and 5-year OS were 92.3% and 76.9%. Median PFS (from diagnosis) was 986 days. 1- and 5-year PFS were 76.9% and 38.2%. Carboplatin was associated with more favorable OS (HR=0.37, 95%CI: 0.04-3.46) and PFS (HR=0.56, 95%CI: 0.16-1.91) in adjusted models (from HIPEC). Female sex and younger age predicted better OS and PFS. Absence of synchronous cancer, and normal platelet count at diagnosis were also associated with better PFS. Conclusions: In this cohort of MPM, CRS-HIPEC was associated with favorable outcomes, with patients occasionally eligible for repeat CRS-HIPEC. Although not statistically significant, our study demonstrated a trend towards improved OS and PFS with carboplatin. Female sex was independently associated with improved OS, despite concurrent endometrial cancers or endometriosis. Several clinical factors predicted PFS.