Outcome of surgical treatment for recurrent thymic epithelial tumors with reference to World Health Organization histologic classification system

Background and Objectives: The aim of this study was to clarify the significance of surgical treatment for recurrent thymic epithelial tumors with reference to the World Health Organization (WHO) histological classification system. Patients: Among 67 patients with tumor recurrence, 22 underwent a re-resection. There were 1 patient with a type AB tumor, 5 with type B1 tumors, 10 with type B2 tumors, 5 with type B3 tumors, and 1 with a carcinoma. Results: The 10-year survival rate following the initial resection was 70% in patients who underwent a re-resection and 35% in those who did not. The average intervals from the initial resection to re-resection were 10.3, 7.8, 6.0, 2.4, and 2.6 years for patients with type AB, 131, 132, 133 tumors, and carcinoma, respectively. The patient with a type AB tumor was alive at 2.4 years after re-resection, 12.7 years after the initial resection. The 5-year survival rates following re-resection in the patients with type 131, 132, and 133 tumors were 100, 56, and 60, respectively. The patient with a carcinoma died as a result of the tumor 2 years after re-resection. Conclusion: WHO histological classification indicates the outcome of surgical treatment for recurrent thymic epithelial tumors.