A Robotic-Assisted Thymectomy is Equivalent to a Transsternal Resection in Large Thymomas

Background: Robotic-assisted thoracoscopic surgery (RATS) is widely accepted for small-to-moderatesize thymomas. However, limited data exists comparing the feasibility of RATS for large tumors >= 5 cm. The aim of this study is to compare the oncological and perioperative outcomes of open thymectomy (OT) versus RATS for these larger tumors. Methods: The National Cancer Database (2010-2020) was queried for patients who underwent RATS and OT. Patients were excluded if they had thymic carcinoma, neoadjuvant therapy, tumors <5 cm, and underwent a video-assisted thoracoscopic approach. The primary outcome was overall survival (OS). Secondary outcomes included length of stay (LOS), 30-day readmission, and mortality rates. Survival outcomes were estimated using the Kaplan-Meier estimator and compared using log-rank test. Propensity score-matched analysis was performed (1:1, Caliper 0.2 without replacement), controlling for age, race, facility type, tumor size, comorbidity index, and year of diagnosis. Results: Of the 1,178 patients identified, 1,015 (86.2%) underwent OT, and 163 (13.8%) underwent RATS. RATS cases were more likely to be performed in academic centers and have a smaller median tumor size compared to OT cases. In the matched cohort, there was no difference between the groups' 30-day readmission, 30-day and 90-day mortality rates. RATS patients had a shorter median LOS compared to OT patients. The median follow-up time was 76 months; 5-year OS was 88% after OT and 90% after RATS (P=0.23). On multivariable Cox regression analysis, the surgical approach was not a predictor of worse survival. Conclusions: Patients who underwent RATS for tumors >= 5 cm had equivalent survival and perioperative outcomes compared to OT with a shorter LOS.