Comparison of Survival by Multimodal Treatment Regimen Among Malignant Pleural Mesothelioma Patients in an Integrated Health System

In order to identify optimal treatment regimens for malignant pleural mesothelioma, we compared overall survival among these patients after various multimodal treatment regimens including combinations of immunotherapy, chemotherapy, and surgery. In 179 patients from 2009 through 2020, multimodal regimens including surgery and immunotherapy were associated with longer survival which supports the use of multi -modal regimens and ongoing investigation of immunotherapy.Background: Optimal therapy for malignant pleural mesothelioma (MPM) remains unclear. We compared overall survival in patients with MPM after various multimodal treatment regimens including combinations of immunotherapy, chemotherapy, and surgery. Patients and Methods: We examined MPM patients treated within our integrated health system from January 1, 2009 to December 31, 2020. Patients were grouped based on treatment regimen: chemotherapy alone (CT), immunotherapy with or without chemotherapy (iCT), surgery with chemotherapy (sCT), and surgery with immunotherapy and chemotherapy (siCT). We analyzed baseline characteristics and overall patient survival among these groups and several subgroups. Results: One hundred seventy-nine patients were included. Among the study groups, there was no difference in age, sex, race/ethnicity, Charlson Comorbidity Index, or Eastern Cooperative Oncol-ogy Group performance status. Patients treated with CT (N symbolscript 109), iCT (N symbolscript 35), sCT (N symbolscript 26), and siCT (N symbolscript 9) had median (95% confidence interval) survivals of 11.7 (9.9-16.3), 18.2 (14.5-29.8), 20.7 (11.6-37.2), and 22.6 (19.7-37.8) months, respectively ( P < .001). Median survival among patients with and without immunotherapy was 19.7 (17.4-29.8) and 12.3 (10.6-17.3) months, respectively ( P symbolscript .023). Median survival among patients with and without surgery was 21.7 (17.6-34.8) and 13.6 (11.5-17.3) months, respectively ( P symbolscript .007). Patients with biphasic/sarcomatoid subtypes who received immunotherapy experienced 76.2% (55.8%-100.0%) 12 month survival vs. 13.6% (4.8%-39.0%) among those who did not ( P < .001). Conclusion: MPM patients receiving surgery and immunotherapy as part of multimodal treat-ment regimens experienced the longest sur vival. Surger y and immunotherapy are each associated with survival. Further investigations are warranted to assess the benefit of immunotherapy within multimodal treatment regimens for MPM.