Minimally invasive surgery in the management of resectable thymoma: a retrospective analysis from the National Cancer Database

BACKGROUND: Thymomas are relatively uncommon tumors traditionally resected via open sternotomy. Despite the appeal of minimally invasive techniques, concerns persist regarding their oncologic efficacy. We hypothesized that minimally-invasive thymectomies for resectable thymomas are oncologically safe when compared to open thymectomy. METHODS: The National Cancer Database (NCDB) was queried for patients with thymoma undergoing resection as the first mode of treatment between 2010–2015. Patient demographics, tumor characteristics and perioperative outcomes were examined for each approach (robotic, thoracoscopic, or open). The primary endpoints were rates of complete (R0) resection and need for adjuvant radiotherapy. Chi-square and Student’s t-test and logistic regression were used for analysis. RESULTS: A total of 2,312 patients were identified. The utilization of myocardial infarction (MI) surgery increased during the study period (robotic: 7.6% to 19.5%; thoracoscopic: 9.3% to 18.4%, both P<0.0001). Median tumor size was higher and mediastinal invasion was more common in open thymectomies. R0 resection was more common in robotic and adjuvant radiotherapy was less frequent in thoracoscopic thymectomies. In multivariate analysis absence of mediastinal invasion (P<0.0001) was the only prognostic factor for R0 resection. Positive margins, mediastinal invasion (both P<0.0001) and younger age (P<0.01) were the only predictors of the need for adjuvant radiotherapy. CONCLUSIONS: Utilization of MI approaches for resectable thymoma has increased from 2010 to 2015. After adjusting for tumor size and mediastinal invasion, minimally-invasive thymectomy was not associated with lower R0 resection rates or increased use of adjuvant radiotherapy. MI thymectomy for resectable thymoma is oncologically equivalent to open thymectomy.