Prolonged Survival in Mesothelioma Patients Without Surgical Resection: A National Cancer Database Analysis.

Background: The Mesothelioma and Radical Surgery 2 (MARS 2) trial demonstrated no survival benefit from cytoreductive surgical resection over chemotherapy alone in resectable pleural mesothelioma. Using the National Cancer Database (NCDB), this study investigated the necessity of surgery for long-term survival in patients with mesothelioma.

Methods: The NCDB was queried for all adult patients with a diagnosis of malignant pleural mesothelioma between 2010 and 2018. Kaplan-Meier analysis compared survival across patient cohorts by treatment, including patients receiving chemotherapy who declined or forewent recommended surgical resection. Survival outcomes were compared with those in patients who underwent chemotherapy and surgical resection, with and without propensity score matching.

Results: Of 21,768 included patients, 9.4% (2045) survived ≥5 years. Among them, 1227 underwent surgical resection, and 708 did not receive any surgical intervention. Multivariable logistic regression modeling identified young age, treatment at an academic center, chemotherapy, epithelioid histologic type, and clinical stage I disease as characteristics associated with improved survival among nonsurgically treated patients. In propensity-matched cohorts, patients receiving chemotherapy and refusing surgical resection (n = 116) had nearly identical 5-year overall survival (OS) rates (16.4%; median OS, 22.9 months [interquartile range, 10.8-38.2 months]) as patients receiving chemotherapy and undergoing surgical resection (n = 232; 16.4% 5-year OS; median OS, 21.9 months [interquartile range, 11.6-50.9 months]; P = .77).

Conclusions: NCDB data align with the randomized MARS 2 findings, showing that long-term survival without curative-intent surgical resection is possible for some patients with mesothelioma. Notably, more than 16% of chemotherapy-treated patients who declined surgical resection survived ≥5 years after diagnosis. Methods to identify patients who are most likely to achieve long-term survival on the basis of clinical or biologic features are needed to refine prognostication and guide treatment.