Thymomectomy versus complete thymectomy in early-stage non-myasthenic thymomas: a multicentric propensity score-matched study

Abstract

Objectives Thymomectomy is gaining consensus over complete thymectomy in early-stage thymoma without myasthenia gravis. This is due both to the difficulty of establishing prospective and randomized controlled studies and to the lack of well defined selection criteria. This bicentric, retrospective propensity-score matched study aims at comparing oncological outcomes, measured in terms of overall survival and thymoma-related survival, in patients undergoing either thymomectomy or complete thymectomy. Methods We retrospectively analyzed medical records of patients with clinical early stage (I and II) thymoma undergoing thymomectomy or complete thymectomy. Exclusion criteria were presence of myasthenia gravis, clinical advanced tumors and thymic carcinoma. A propensity-score matching analysis was applied in order to reduce potential preoperative selection biases such as comorbidity (Charlson score), tumour maximal diameter and surgical approach (open vs minimal). All variables were dichotomized. Results A total of 255 patients were enrolled from two different Hospitals, 126 underwent complete thymectomy and 129 a thymomectomy. Disease-free and thymoma-related survivals showed a 5-year rate of 87.7% and 96.0% and a 10-year rate of 82.2% and 91.9%, respectively. Propensity score-matching analysis selected a total of 176 patients equally divided between the two groups. No difference was found for both disease-free (p = 0.11) and thymoma-related (p = 0.37) survival in the two groups of resection. Multivariable Cox regression analysis showed that histology (p < 0.001), residual disease (p < 0.001) and adjuvant chemotherapy (p < 0.001) were the only predictors of shorter disease free survival. Whereas there was no evidence to confirm that disease-free and thymoma related survivals were influenced by resection extent. Conclusions Thymomectomy is an adequate surgical resection for non-myasthenic thymoma, achieving disease-free and thymoma-related survivals comparable to those after complete thymectomy.