Positron Emission Tomography in Thymic Tumors: Analysis Using a Prospective Research Database

Background: Positron emission tomography may have a role in the pretreatment workup of patients with thymic malignancies. This study was undertaken to determine the utility of the maximum standardized uptake value (SUV_max) in predicting histologic type and tumor stage in a large cohort of thymic epithelial tumors.

Methods: The large, multiinstitutional, prospective database of The International Thymic Malignancy Interest Group (ITMIG) was queried for the use of positron emission tomography in the pretreatment workup of patients with thymic tumors. Data analyzed included demographics, SUV_max, histologic tumor type, and tumor stage. The distribution of SUV_max according to histologic type and Masaoka-Koga pathologic stage was determined, and the ability of SUV_max to predict these two variables was calculated using analysis of receiver operating characteristic curves.

Results: Since 2012, data from 926 patients with thymic malignancies were entered into the ITMIG prospective database, of which 154 had a reported value for SUV_max. The area under the receiver operating characteristic curve for SUV_max in predicting histologic type and pathologic stage was 0.79 (95% confidence interval, 0.70 to 0.88; p < 0.001) and 0.81 (95% confidence interval, 0.73 to 0.88; p < 0.001), respectively. In addition, there was a significant relationship between SUV_max and histologic type (p < 0.001) as well as Masaoka-Koga pathologic stage (p < 0.001).

Conclusions: Positron emission tomography has utility in predicting clinicopathologic features of thymic malignancies. These results may have clinical application in the pretreatment workup of patients with these rare tumors.