Treatments and outcomes of spinal metastasis from thymic epithelial tumors: 10-year experience with 15 patients in a single center.

PURPOSE: Although thymic epithelial tumors (TETs) are rare, their spinal metastases are even rarer, and they have only been described in a few case reports. The aim of the present study is to discuss the possible treatments and outcomes of patients with spinal metastasis from TETs. METHODS: Included in this retrospective study were 15 patients with metastasis of TETs who received either radical or debulking surgery plus radiochemotherapy as adjuvant therapy in our center between 2007 and 2017. Possible prognostic factors for progression-free survival (PFS) and overall survival (OS) were analyzed by log-rank analysis. RESULTS: Our series comprised seven men and eight women, with a median age of 52 years. The period from the primary diagnosis to spinal metastasis varied from 0 to 16 months. The metastatic lesions were mainly located in the thoracic spine (n = 11; 73.3%), followed by the cervical and lumbar spine (n = 2; 13.3%, respectively). The median follow-up period was 28 months. Local tumor progression was detected in four patients (26.7%), and seven patients (46.7%) died of the disease during the follow-up period. Log-rank analysis indicated that radical resection was associated with longer PFS, whereas PFS, response to systemic chemotherapy and WHO B1-B2 were favorable factors of OS for patients with spinal metastatic TETs. CONCLUSIONS: Radical surgery is associated with longer PFS, while PFS is associated with better OS. Postoperative radiotherapy seems to be a useful supplementary treatment after debulking surgery, and patients who respond to postoperative chemotherapy were demonstrated with greater OS. WHO type B3-C seemed to be an adverse factor for spinal metastasis from TETs. These slides can be retrieved under Electronic Supplementary Material.