Mesonephric and mesonephric-like adenocarcinomas of gynecologic origin: A single-center experience with molecular characterization, treatment, and oncologic outcomes

Objectives Mesonephric (MA) and mesonephric-like (MLA) adenocarcinomas are rare cancers, and data on clinical behavior and response to therapy are limited. We sought to report molecular features, treatment, and outcomes of MA/MLA from a single institution. Methods Patients with MA (cervix) or MLA (uterus, ovary, other) treated at Memorial Sloan Kettering Cancer Center (MSK) from 1/2008–12/2021 underwent pathologic re-review. For patients with initial treatment at MSK, progression-free survival (PFS1) was calculated as time from initial surgery to progression or death; second PFS (PFS2) was calculated as time from start of treatment for recurrence to subsequent progression or death. Overall survival (OS) was calculated for all patients. Images were retrospectively reviewed to determine treatment response. Somatic genetic alterations were assessed by clinical tumor-normal sequencing (MSK-Integrated Mutation Profiling of Actionable Cancer Targets [MSK-IMPACT]). Results Of 81 patients with confirmed gynecologic MA/MLA, 36 received initial treatment at MSK. Sites of origin included cervix (n = 9, 11%), uterus (n = 42, 52%), ovary (n = 28, 35%), and other (n = 2, 2%). Of the 36 patients who received initial treatment at MSK, 20 (56%) recurred; median PFS1 was 33 months (95% CI: 17-not evaluable), median PFS2 was 8.3 months (95% CI: 6.9–14), and median OS was 87 months (95% CI: 58.2-not evaluable). Twenty-six of the 36 patients underwent MSK-IMPACT testing, and 25 (96%) harbored MAPK pathway alterations. Conclusion Most patients diagnosed with early-stage disease ultimately recurred. Somatic MAPK signaling pathway mutations appear to be highly prevalent in MA/MLA, and therapeutics that target this pathway are worthy of further study.