Malignant Peritoneal Mesothelioma: National Practice Patterns, Outcomes, and Predictors of Survival.

PURPOSE: This study of a large, contemporary national database evaluated management patterns, outcomes, and prognostic factors of malignant peritoneal mesothelioma (MPM) in the USA.

METHODS: The National Cancer Data Base was queried for newly diagnosed nonmetastatic MPM. Patients were divided into five cohorts: observation, chemotherapy alone, cytoreductive surgery (CRS) alone, CRS/chemo [referring to any non-hyperthermic intraperitoneal chemotherapy (HIPEC) chemotherapy], and CRS/HIPEC. Statistics included multivariable logistic regression, Kaplan-Meier analysis, and Cox proportional hazards modeling.

RESULTS: Of 1514 patients, 379 (25%) underwent observation, 370 (24%) received chemotherapy only, 197 (13%) CRS alone, 352 (23%) CRS/chemo, and 216 (14%) CRS/HIPEC. No major temporal trends in management were noted. Factors predictive of CRS administration included younger age, female gender, insurance status, residence in educated areas, living farther from treating institutions, and treatment at academic centers (p < 0.05 for all). Compared with epithelioid histology, those with sarcomatoid and biphasic histology were less and more likely to undergo CRS, respectively (p < 0.05 for both). In all CRS patients, 30- and 90-day mortality rates were 0.8 and 1.2%, respectively. At median follow-up of 50 months, median OS in the respective groups was 6, 17, 21, 52, and 61 months (p < 0.001). Poor prognostic factors included advanced age, male gender, uninsured/Medicaid insurance, and sarcomatoid/biphasic histology (p < 0.05 for all).

CONCLUSIONS: In the USA, MPM is treated using a wide variety of strategies. Many factors impact the type of treatment delivered, including age, sociodemographics, geography, histology, and facility type. Although these data do not imply causation, combined-modality management seems associated with the longest OS.