Due to lacking of evidence on surveillance for gastric neuroendocrine carcinoma (G-NEC), this study aimed to determine the optimal postsurgical surveillance strategy for G-NEC patients and compare its cost-effectiveness with traditional surveillance strategies.

The development of existing follow-up strategies is mainly based on experts' consensus and researches on recurrence patterns due to the lack of direct evidence and unified standards. On the one hand, it is unreasonable to carry out the same postoperative surveillance for all G-NEC patients. In addition to the early detection of recurrence, the optimal follow-up strategy should also balance cost and effectiveness. There were no criteria for the arrangement of follow-up in different guidelines, and the optimal postoperative follow-up strategy for patients with G-NEC remains unclear. Patients with G-NEC from 21 centers in China were included. Cost-effectiveness were assessed by Markov model.

Inclusion Criteria:This multicentre retrospective study included patients with gastric neuroendocrine neoplasms who underwent surgery in 21 centres of the Study Group for Gastric Neuroendocrine Tumours in China from January 2008 to December 2016. Radical surgery included a D2 lymphadenectomy consistent with the Japanese gastric cancer treatment guidelines.

Exclusion Criteria: Patients with tumours of unknown pathology (only neuroendocrine neoplasms recorded without detailed information); patients with gastric NETs; patients who had endoscopic submucosal dissection or endoscopic mucosal resection; patients who received neoadjuvant chemotherapy; patients who died within 3 months of surgery from postoperative complications; and patients with unknown tumour size or who were lost to follow-up

A total of 801 G-NEC patients from 21 centers in China were included.