Postoperative radiotherapy may be a favorable treatment for thymic neuroendocrine tumors (TNET), according to a study published in Thoracic Cancer. TNETs are rare, accounting for only 5% of all thymic neoplasms, and are defined separately from thymomas. They are especially aggressive and are associated with poorer survival outcomes. 

The recommended option for curative treatment is surgical resection, but the prognosis remains poor, likely due to high rates of recurrence. Postoperative radiotherapy (PORT) has been suggested as an adjuvant therapy to prevent recurrence after surgical resection in thymoma and thymic carcinoma, but its efficacy remains unclear in patients with TNET. 

In the study, the researchers used the Surveillance, Epidemiology and End Results (SEER) database to retrospectively identify and compare patients with TNET (293), thymoma (2788), or thymic carcinoma (866) between 1998 and 2015. 

A higher number of patients with TNET were men, younger, had a well or moderately differentiated histological grade, later disease stage at diagnosis, and were more likely to have regional lymph node metastasis. The median overall survival and cancer-specific survival for patients with TNET was 82.9 months, which was significantly shorter than the 101.9 months experienced by patients with thymoma

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Debulking resection had significantly inferior survival outcomes when total/radical resection were compared. Notably, postoperative radiotherapy positively impacted overall survival and cancer-specific survival in Masaoka-Koga stage III-IV TNET, as well as overall survival in TNET stage IIB. 

According to the study authors, “this is the first propensity-matched analysis of SEER data, which not only demonstrated the role of complete surgical resection but also the favorable effect of PORT in specific subgroups of TNET. However, because of the rarity of this disease, prospective analysis is still lacking and further investigation is necessary.” 

Reference

Wen J, Chen J, Chen D, et al. Evaluation of the prognostic value of surgery and postoperative radiotherapy for patients with thymic neuroendocrine tumors: a propensity-matched study based on the SEER database[published online October 1, 2018]. Thoracic Cancer. doi: 10.1111/1759-7714.12868