Chemoradiotherapy is an alternative choice for patients with primary mediastinal seminoma.

Background: The low incidence of primary mediastinal seminomas has precluded the development of clinical trials on mediastinal seminomas. We investigated the clinicopathologic characteristics, prognosis of patients with primary mediastinal seminomas as well as the efficiency of nonsurgical treatments compared with treatments containing surgery.

Methods: We retrospectively collected data on the clinicopathologic characteristics, treatments, toxicities, and survival of 27 patients from a single center between 2000 and 2018. Patients were divided into two groups according to whether they received operation. Survivals were assessed using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test.

Results: The median age was 28 (13-63) years. The most common symptoms were chest pain (29.6%), cough (25.9%), and dyspnea (22.2%). There were 13 and 14 patients in surgery and non-surgery group. Patients in the non-surgical group were more likely to be with poor performance scores (100% vs. 76.9%) and disease invaded to adjacent structures (100% vs. 76.9%) especially great vessels (100% vs. 46.2%).The median follow-up period was 32.23 (2.7-198.2) months. There was no significant difference of overall survival (5-year 100% vs. 100%), cancer-specific survival (5-year 100% vs. 100%), local regional survival (5-year 91.7% vs. 90.0%, p = 0.948), distant metastasis survival (5-year 90.9% vs. 100.0%, p = 0.340) and progression-free survival (82.5% vs. 90.0%, p = 0.245) between patients with and without surgery.

Conclusions: Primary mediastinal seminoma was with favorable prognosis, even though frequently invasion into adjacent structures brings difficulties to surgery administration. Chemoradiotherapy is an alternative treatment with both efficacy and safety.