Characteristics and Treatment Outcomes of Primary Mediastinal Seminomas: A Report of 30 Cases from a Single Center

Abstract

The low incidence primary mediastinal seminoma has precluded the development of clinical trials, and present knowledge is based on case reports and tiny studies. We performed this single-center retrospective analysis to evaluate the clinical characteristics, treatments, and prognosis in patients with pathologically confirmed primary mediastinal seminoma. Data regarding clinicopathologic characteristics, treatment protocols, toxicities, and survival were collected from 30 patients who attended our institution between December 2000 and December 2018. Survival was assessed using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test. The 30 patients were with a median age of 30 years old (13-63 years). Chest pain, stuffiness and cough were the most common symptoms (22.2%,22.2%, 13.9%). The medium maximum diameter of primary tumor was 10.2 centimeters. Eighteen patients were with invasion of adjacent structures such as lung and superior vena vessel. Three and two patients were diagnosed as lymph node metastasis and distant metastasis. R0 resection and debulking resection were performed in 12(40.0%) and 2(6.7%) patients, respectively. Treatment comprised radiotherapy in 15(50.0%) patients and chemotherapy in 27(90.0%). The median radiation dose was 45Gy and the most widely used chemotherapy regimens were bleomycin, etoposide and cisplatin. The median follow-up time was 25.1months(1.8 -198.2 months). At the last follow up, two patients died. Both two patients lived more than ten years after treatment and neither of them died of seminomas or treatment induced toxicities. Local recurrence and distant metastasis were observed in 3 patients each. At 5 years and 10 years, local-regional relapse free survivals were 86.7% and 86.7%, overall survivals were 100% and 100%, progression-free survivals were77.4% and 77.4%, and distant metastasis–free survivals were 85.6% and 85.6%, respectively. In univariate analysis, there is a marginal differences of local regional relapse free survival between patients who received radiotherapy and who did not (100% vs. 74.3%, p=0.081). Primary mediastinal seminoma was frequently diagnosed with invasion of adjacent structures. Chemotherapy is the most widely used treatment and radiotherapy may increase local-regional relapse free survival.