To investigate the appropriate surgical approach for thymic tumors with a diameter ≥5 cm in our center, and to provide the treatment strategies of massive thymoma.

A retrospective analysis was conducted in our hospital, which included 113 patients with thymic tumors ≥5 cm in diameter and underwent surgical R0 resection. The patients were divided into video-assisted thoracoscopic thymectomy (VATT) group (n=48) and conventional thymectomy group (n=65) according to surgical methods. The basic clinical information were compared between the two groups.

The intraoperative blood loss (P=0.001) and postoperative chest/mediastinal canal drainage volume (P=0.005) in the VATT group were less than those in the conventional thymectomy group, and the risk of postoperative pulmonary infection was lower than that in the conventional thymectomy group (P=0.023) . Lung invasion (P=0.006) and pericardial invasion (P=0.002) in VATT group were less than those in conventional thymectomy group. In addition, the tumor diameter of VATT group was smaller than that of conventional thymectomy group (P<0.001) , and the proportion of Masaoka stage Ⅰ–Ⅱ patients was higher than that of conventional thymectomy group (P<0.001) . There was no significant difference in overall survival (P=0.075) and disease-free survival (P=0.058) between two groups. Logistic regression analysis suggested that tumor diameter ≥9 cm (OR=12.506, 95%CI: 2.398–65.214, P=0.003) and Masaoka stage ≥ Ⅲ (OR=25.788, 95%CI: 4.262–156.027, P<0.001) were positively associated with conventional thymectomy surgery.

VATT is a safe surgical approach for patients with thymic tumors ≥5 cm, which resulted in similar prognosis as conventional thymectomy surgery. However, conventional thymectomy seems more appropriate for patients with thymic tumors diameter ≥9 cm or Masaoka stage Ⅲ or above.