Impact of guideline therapy on survival of patients with stage I-III epithelioid mesothelioma

Background: Modern treatment guidelines recommend multimodal therapy with at least chemotherapy and surgery for patients with potentially resectable epithelioid mesothelioma. This study evaluated guideline compliance for patients with stage I-III epithelioid mesothelioma and tested the hypothesis that guideline-concordant therapy improved survival.Methods: The National Cancer Database was queried for patients with stage I-III epithelioid malignant pleural mesothelioma between 2004 and 2016. The impact of therapy was evaluated using logistic regression, Kaplan-Meier analysis, Cox-proportional hazards analysis, and propensity-scoring methods.Results: During the study period, guideline-concordant therapy was used in 677 patients (19.1%), and 2,857 patients (80.8%) did not have guideline-concordant therapy. Younger age, being insured, living in a census tract with a higher income, clinical stage, and being treated at an academic or research program were all predictors of receiving guideline-concordant therapy in multivariable analysis. Guideline-concordant therapy yielded improved median survival [24.7 (22.4-26.1) vs. 13.7 (13.2-14.4) months] and 5-year survival [17.7% (14.7-21.3%) vs. 8.0% (7.0-9.3%)] (P<0.001), and continued to be associated with better survival in both multivariable analysis and propensity-matched analysis. In the patients who received guideline therapy, median survival [24.9 (21.9-27.2) vs. 24.5 (21.7-28.1) months] and 5-year survival [14.9% (10.9-20.2%) vs. 20.1% (16.0-25.4%)] was not significantly different between patients who underwent induction (n=304) versus adjuvant (n=373) chemotherapy (P=0.444).Conclusions: Guideline-concordant therapy for potentially resectable epithelioid mesothelioma is associated with significantly improved survival but used in a minority of patients. The timing of chemotherapy with surgery in this study did not have a significant impact on overall survival.