Resection of the primary tumor improves the prognosis of gastrointestinal neuroendocrine neoplasms with liver metastases: mutual validation based on SEER database and institutional data. - Liu, Yifan; Wang, Zhixiong; Lin, Qi; Cui, Ruizhe; Tang, Wei; Li, Guanghua; Wang, Zhao (BMC Gastroenterology, 2023)