Results of treatment for thymic neuroendocrine tumours: multicentre clinicopathological study

OBJECTIVES: A thymic neuroendocrine tumour (TNET) is rare, and few comprehensive reports of treatment results have been presented. To clarify the clinicopathological characteristics of TNET in affected patients, outcomes were retrospectively examined using cases accumulated in a multicentre survey. METHODS: Thirty patients (25 men and 5 women) who underwent surgical resection or biopsy procedures at 10 institutions of the Thoracic Surgery Study Group of Osaka University (TSSGO) between January 1986 and June 2015 and pathologically diagnosed with TNET were enrolled. RESULTS: The examined tumours were classified as typical carcinoid in 7 patients, atypical carcinoid in 11 patients, large-cell neuroendocrine carcinoma in 3 patients and small-cell carcinoma in 9 patients, of which 2 underwent surgical biopsy procedures and 28 surgical resection, with a macroscopic complete resection procedure performed in 27 patients. Induction therapy was performed in 2 patients and adjuvant therapy in 10 patients. Thirteen patients had recurrence, with distant metastasis, especially in bone and lung tissues, more frequent than local recurrence. Overall survival was 77% after 5 years and 35% after 10 years, whereas relapse-free survival was 48% and 29%, and cancer-specific survival was 90% and 48%, respectively. Overall survival was significantly better in patients who underwent macroscopic complete resection (P = 0.010). As for relapse-free survival patients, TNM Stage I or II (P = 0.011) and received adjuvant therapy patients (P = 0.042) showed good survival rates. CONCLUSIONS: The prognosis of patients with TNET was favourable in those treated with macroscopic complete resection. Survival is promising even in patients with postoperative recurrence, following treatment utilized for pulmonary neuroendocrine tumour or gastroenteropancreatic neuroendocrine tumour.