Determinants of Complete Resection of Thymoma by Minimally Invasive and Open Thymectomy: Analysis of an International Registry

Abstract

INTRODUCTION Minimally invasive thymectomy (MIT) is a surgical approach to thymectomy that has more favorable short-term outcomes than open thymectomy (OT) for myasthenia gravis. When performed for thymoma, the oncologic outcomes of MIT have not been rigorously evaluated. We analyzed determinants of complete (R0) resection among patients undergoing MIT and open thymectomy in a large international database. METHODS The retrospective database of the International Thymic Malignancy Interest Group (ITMIG) was queried. Chi-Square and Wilcoxon rank-sum tests, multivariate logistic regression models, and propensity matching were performed. RESULTS A total of 2514 patients underwent thymectomy for thymoma between 1997 and 2012. 2053 (82%) patients underwent OT, 461 (18%) patients underwent MIT, and the use of MIT increased significantly in recent years. The rate of R0 resection among patients undergoing OT was 86%, and among those undergoing MIT was 94%, respectively (p<0.0001). In propensity matched MIT and OT groups (n=266 each group), however, the rate of R0 resection did not differ significantly (MIT 96%, OT 96%, p=0.7). Multivariate analyses were performed to identify determinants of complete resection. Factors independently associated with R0 resection were geographical region, later time period, less advanced Masaoka stage, total thymectomy, and the absence of radiotherapy. Surgical approach, whether minimally invasive or open, was not associated with completeness of resection. CONCLUSIONS The use of MIT for resection of thymoma is increasing substantially over time, and MIT can achieve similar rates of R0 resection for thymoma as OT.

A systematic review of robotic versus open and video assisted thoracoscopic surgery (VATS) approaches for thymectomy

“…All of the studies were non-randomized and most were retrospective, so they were at higher risk of bias than a randomized-controlled trial (RCT). Several of the studies had a high risk of selection bias due to historical controls (24,32,34,36,37), differences in criteria for patient selection (22,33), or patient characteristic differences between groups (23). Studies that performed propensity score matching for outcomes of interest were considered at low risk for selection bias (25,(27)(28)(29)(30)35), as were the papers by Qian et al (31) and Ye et al (39), due to contemporary controls, the same selection criteria, and no differences in patient characteristics.…”

“…Five studies were assessed as having a high risk of reporting bias. The study by Burt et al (23) did not report data separately for the robotic group, except for an unmatched margin rate. In many studies (24,26,32,36), outcomes of interest were reported incompletely (e.g., missing a measure of variance), such that they could not be entered into the meta-analysis.…”

Robotic Thymectomy Is Feasible for Large Thymomas: A Propensity-Matched Comparison

“…These results are consistent with those published by Wilshire and colleagues [12] who reported an R0 rate of 91% in their series of robotic thymectomy for 23 patients with thymomas larger than 3 cm (range 3 to 13 cm). In a recent analysis of the International Thymic Malignancies Interest Group registry data, Burt and colleagues [20] analyzed factors associated with R0 resection after thymectomy in 2053 thymoma patients. R0 resection rate after minimally invasive resection of thymoma was 94% in that study.…”

How to get the best from robotic thoracic surgery

“…Nowadays, little data with an adequate follow-up exists on oncological outcomes, nevertheless, the literature confirms the high rate (almost 90%) of complete R0 resections which is guaranteed both using the robotic system and open approach (8,9).…”