Impact of Mesothelioma Histologic Subtype and Use of Cancer-Directed Surgery on Outcomes in the National Cancer Database

Abstract

<h3>Purpose/Objective(s)</h3> To evaluate the impact of malignant pleural mesothelioma (MPM) histology subtype and the use of surgery on overall survival. <h3>Materials/Methods</h3> Multivariable Cox proportional hazards modeling and propensity score-matched analysis was performed to evaluate the overall survival of patients with stage I-IIIA MPM who underwent cancer-directed surgery or nonoperative management stratified by subtype of MPM. Patients who were coded in the National Cancer Database (NCDB) as not having undergone surgery because surgery "was contraindicated due to patient risk factors (comorbid conditions, advanced age, progression of tumor prior to planned surgery, etc.)" were excluded from analysis. <h3>Results</h3> Of 6,778 patients who had stage I–IIIA MPM during the study period, histologic subtype was epithelioid in 4,783 patients (70%), sarcomatoid in 1,060 patients (16%), and biphasic in 935 patients (14%). Median survival was 17 months in the epithelioid group, 5 months in the sarcomatoid group, and 11 months in the biphasic group (<i>P</i> < 0.01). Among patients who underwent surgery, median survival was 26 months in the epithelioid group, 9 months in the sarcomatoid group, and 15 months in the biphasic group (<i>P</i> < 0.01). In multivariable analysis, cancer-directed surgery was associated with improved survival in the epithelioid (adjusted hazard ratio [aHR] 0.75 [95% CI: 0.68-0.82]; <i>P</i> < 0.01) and biphasic (aHR 0.78 [95% CI: 0.64-0.95]; <i>P</i> = 0.02) groups but not in the sarcomatoid (aHR 0.82 [95% CI: 0.64-1.05]; <i>P</i> = 0.11) group, when compared to nonoperative management. Propensity-score matching was used to create 2 groups of 725, 109, and 174 patients with epithelioid, sarcomatoid, and biphasic MPM, respectively, each of whom received cancer-directed surgery or nonoperative management and were well-matched with regard to 12 common prognostic covariates including comorbidities, clinical stage, and T and N status. Surgery was associated with improved median survival in the epithelioid (21.9 months [95% CI: 20.1-23.9] vs. 16.8 months [95% CI: 15.4-17.8]; <i>P</i> < 0.01) and biphasic (12.2 months [95% CI: 11.3-14.6] vs. 10.7 months [95% CI: 9.5-11.9]; <i>P</i> < 0.01) groups but not in the sarcomatoid (7.8 months [95% CI: 6.2-11.7] vs. 6.9 months [95% CI: 6.0-7.9]; <i>P</i> < 0.01) group. <h3>Conclusion</h3> In this national analysis, we found that cancer-directed surgery is associated with significantly improved survival for stage I-IIIA MPM patients with epithelioid and biphasic histologies. Patients with sarcomatoid histology have poor prognosis and do not benefit from cancer-directed surgery. Our findings support current National Comprehensive Cancer Network (NCCN) guidelines recommending surgery for only epithelioid and biphasic histologies.