P3.03-031 Definitive Radiation Therapy is Associated with Improved Survival in Non-Metastatic Malignant Pleural Mesothelioma: Topic: Mesothelioma Clinical

Abstract

To analyze rates of definitive radiation therapy (RT) utilization for malignant pleural mesothelioma (MPM) and evaluate the association between RT and overall survival (OS). The National Cancer Data Base (NCDB) was queried to identify patients with non-metastatic MPM diagnosed between 2004 and 2013. Definitive RT was defined as receipt of 40-65 Gy of external beam radiation therapy to the chest wall, lungs, or pleura. Multivariate logistic regression was performed to identify predictors of RT receipt. OS was estimated using the Kaplan-Meier method. Cox proportional hazards models were used to identify predictors of mortality. Propensity score matching was performed to verify the effect of definitive RT on OS. Among 14,090 MPM patients, 3.6% received RT. Younger age, lower co-morbidity score, private insurance, surgical resection, and receipt of chemotherapy were associated with increased RT utilization. Patients who received RT had higher crude 2 and 5-year OS rates (33.9% and 12.6%, respectively) compared to patients who did not (19.5% and 5.3%, respectively; p<0.001). On multivariable analysis and propensity matched analysis, definitive RT was associated with improved survival (adjusted hazard ratio [adj HR] 0.78, 95% CI 0.70-0.87) and (adj HR 0.77, 95% CI 0.67-0.89), respectively. Compared to no therapy, surgery and RT (adj HR 0.41, 95% CI 0.31-0.54) and trimodality therapy (adj HR 0.47, 95% CI 0.40-0.55) were associated with the best survival.Tabled 1Comparison of Overall Survival According to Definitive RT2-yr rate95% CI5-yr rate95% CIpAdjusted HR95% CINo RT19.5%18.8-20.35.3%4.9-5.8<0.0011.00RefRT33.9%29.4-38.412.6%9.4-16.3<0.0010.780.70-0.87 Open table in a new tab The rate of definitive RT utilization for non-metastatic MPM has remained low over the past decade. Patients who received RT had improved OS, suggesting a role for increased utilization, particularly with the advancement in RT techniques. Combined modality therapy was associated with a greater improvement in survival than any single modality treatment.