Minimally Invasive Thymectomy Could Be Attempted for Locally Advanced Thymic Malignancies: A Real-World Study With Propensity Score-Matched Analysis

Introduction: Increasing evidence supports minimally invasive thymectomy (MIT) for early stage thymic malignancies than open median sternotomy thymectomy (MST). Nevertheless, whether MIT could be attempted for locally advanced disease remains unclear.

Methods: The clinical data of consecutive patients with stage T2-3NxM0 (eighth edition TNM staging) thymic malignancies who underwent MIT or MST were identified from a prospectively maintained database. The co-resected structures were rated with a resection index to evaluate surgical difficulty. The impact of surgical approach on treatment outcomes was investigated through propensity score-matched analysis and multivariable analysis.

Results: From January 2008 to December 2019, a total of 128 patients were included; MIT was initially attempted in 58 (45.3%) cases, and eight (13.8%) were converted to MST during surgery. The conversion group had similar perioperative outcomes to the MST group, except for a longer operation time. After propensity score matching, the resection index scores were similar between the MIT and MST groups (3.5 versus 3.7, p = 0.773). The MIT group had considerably less blood loss (p < 0.001), fewer postoperative complications (p = 0.048), a shorter duration of chest drainage (p < 0.001), and a shorter hospitalization duration (p < 0.001) than the MST group. The 5-year freedom from recurrence rate was not different between the two groups (78.2% versus 78.5%, p = 0.942). In multivariable analysis, surgical approach was not associated with freedom from recurrence (p = 0.727).

Conclusions: MIT could be safely attempted in carefully selected patients with locally advanced thymic tumors. Conversion did not compromise the surgical outcomes. Patients may benefit from the less traumatic procedure and thus better recovery, with comparable long-term oncologic outcomes.