P03: Thymic neuroendocrine tumors: analysis of factors affecting survival

Background: Thymic neuroendocrine tumors (NETT) are very rare tumors. This study was designed to identify factors affecting survival including the impact of surgical resection.

Methods: We queried the Surveillance, Epidemiology and End Results database for all patients diagnosed with NETT from 1988 to 2011. We excluded patients diagnosed at autopsy. Variables significantly affecting survival in univariate analysis were included in a multivariate analysis.

Results: We identified 254 patients with NETT. Median overall survival was 73 months, and 10-year survival was 71%. Multivariate analysis demonstrated that female sex, lower Masaoka-Koga (MK) stage, and surgical resection were significant factors affecting survival. Surgery was performed in 139/254 (54.7%) patients. The majority, 131/139 (94.2%) had resection of the tumor, 8/139 (5.8%) had debulking. There were no significant differences between patients undergoing surgery and those not, except for higher MK stage among patients not undergoing surgery (P=0.018). Median survival in patients who underwent surgery was 109 months compared to 46 months in patients who did not undergo surgery (P<0.001). In patients who underwent surgery, 69/139 (49.6%) had nodal sampling and 38/69 (55.1%) had positive nodal metastases. Multivariate analysis demonstrated that MK stage and positive nodal metastases were the only factors impacting overall survival. Postoperative radiation therapy did not affect survival.

Conclusions: In patients with NETT, surgical resection, MK stage, and female sex are important factors impacting survival. In patients submitted to surgery, MK stage and nodal sampling significantly impacted survival. In this rare disease, surgical therapy appears to be the intervention of choice.

Keywords: SEER; thymic neuroendocrine tumors (NETT)