Preoperative CT findings of thymoma are correlated with postoperative Masaoka clinical stage

Abstract

Rationale and objectives: Both preoperative computed tomography (CT) staging and postoperative surgical Masaoka clinical staging are of great clinical importance for diagnosing thymomas. Our study aimed to investigate the relationships between these two staging systems.

Materials and methods: This was a retrospective review of 129 patients who had undergone thymoma surgery. Helical CT and 16-slice CT were performed preoperatively. Surgical findings were evaluated according to the Masaoka clinical staging system.

Results: A significant association was shown between Masaoka clinical staging and CT staging, especially of features including tumor size (P = .004), tumor shape (P < .001), tumor density (P < .001), capsule completeness (P < .001), and involvement of surrounding tissues (P < .001). Based on the CT findings, there were 35.09% of Masaoka stage I patients who had a tumor size <5 cm as compared to 14.81% of stage IV patients. Only 8.77% of Masaoka stage I patients had a tumor size ≥10 cm as compared to 40.74% of stage IV patients. In stages III and IV, most tumors were irregularly shaped with an uneven density and incomplete capsule. Invasive tumors were more frequently found in stages III (81.48%) and IV (88.89%) than in stages I (0%) and II (38.89%). The incidence of myasthenia gravis was comparable in different stages. Consistency between CT and Masaoka clinical stages was higher in stage I (37.98%) than other stages (approximately 10%).

Conclusion: This study documented a close relationship between preoperative CT thymoma staging and postoperative Masaoka clinical staging. Thus, preoperative CT findings can be beneficial for determining the proper management and prognosis of thymoma patients.