Thymoma Recurrence and its Predisposing Factors in Iranian Population: a Single Center Study

Background: Thymoma is relatively rare tumor. Prognosis and patients' outcome vary across different studies. We aimed to study the predisposing factors causing tumor recurrence in thymoma patients. Materials and Methods: A total of 43 thymoma or thymic carcinoma patients treated at the National Institute of Tuberculosis and Lung Disease (NRITLD), Masih Daneshvari Hospital from September 2005 to January 2017 were evaluated. The primary endpoint was the progression free survival (PFS). The relation of predisposing factors to PFS was studied. Results: Median age was 55 years old. The mean of follow-up duration was 22.9 months. The most prevalent pathology was thymoma unspecified. Pure red cell aplasia (n=3, 6.9%) was the most prevalent Para neoplastic syndrome. Most of the patients (n=23, 54%) were in stage III and IV Masaoka-Koga staging system. Disease progression was observed in 17 patients (39. 5%). Most recurrences occurred locally. None of demographic characteristics differed between patients who experienced disease recurrence and those who did not. After univariate and multivariate analysis, predisposing factor for disease progression was only Masaoka-Koga stage (P- value=0.015 and 0.031 respectively). Conclusion: In this study, among different probable predisposing factors, only Masaoka-Koga stage had significant effect on disease recurrence. Large casecontrol studies may be required for better evaluation of risk factors.