Survival by Histologic Subtype of Malignant Pleural Mesothelioma and the Impact of Surgical Resection on Overall Survival

Abstract

Introduction: For the 3 histologic subtypes of malignant pleural mesothelioma (MPM)-epithelioid, sarcomatoid, and biphasic-the magnitude of benefit with surgical management remains underdefined.

Materials and methods: The National Cancer Data Base was queried for newly diagnosed nonmetastatic MPM with known histology. Patients in each histologic group were dichotomized into those receiving gross macroscopic resection versus lack thereof/no surgery. Kaplan-Meier analysis evaluated overall survival (OS) between cohorts; multivariable Cox proportional hazards modeling assessed factors associated with OS. After propensity matching, survival was evaluated for each histologic subtype with and without surgery.

Results: Overall, 4207 patients (68% epithelioid, 18% sarcomatoid, 13% biphasic) met the study criteria. Before propensity matching, patients with epithelioid disease experienced the highest median OS (14.4 months), followed by biphasic (9.5 months) and sarcomatoid (5.3 months) disease; this also persisted after propensity matching (P < .001). After propensity matching, surgery was associated with significantly improved OS for epithelioid (20.9 vs. 14.7 months, P < .001) and biphasic (14.5 vs. 8.8 months, P = .013) but not sarcomatoid (11.2 vs. 6.5 months, P = .140) disease. On multivariable analysis, factors predictive of poorer OS included advanced age, male gender, uninsured status, urban residence, treatment at community centers, and T4/N2 disease (all P < .05). Chemotherapy and surgery were independently associated with improved OS, as was histology (all P < .001).

Conclusion: This large investigation evaluated surgical practice patterns and survival by histology for MPM and found that histology independently affects survival. Gross macroscopic resection is associated with significantly increased survival in epithelioid and biphasic, but not sarcomatoid, disease. However, the decision to perform surgery should continue to be individualized in light of available randomized data.

Keywords: Biphasic; Epithelioid; Histology; Sarcomatoid; Surgery.