The Risk of Second Primary Gastrointestinal Malignancies Following Primary Gastrointestinal Carcinoid Tumors: a SEER Based Study 2000-2022

Carcinoid tumors are rare neuroendocrine tumors with slowly progressive course. Carcinoid tumors are the most common gastrointestinal (GI) neuroendocrine tumors. The most common sites of GI carcinoids are small intestine accounting for 45%, rectum (20%), appendix (17%), colon (11%), and stomach (7%). Some studies reported an association between neuroendocrine tumors and multiple malignancies. However, the presence of neuroendocrine tumors combined with multiple primary GI tumors is considered an exotic event in the literature with only few case studies and case series. So the aim of this study is to assess the risk of GI malignancies following primary GI carcinoids.