Incidence and risk factors of gastrointestinal neuroendocrine neoplasm metastasis in liver, lung, bone, and brain: A population-based study.

Background: Neuroendocrine neoplasm is a rare solid tumor. Metastatic pattern of the gastrointestinal neuroendocrine neoplasm (GI-NEN) has not been fully explored.

Methods: Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database (SEER-9 registry) from 1973 to 2015. Incidence was estimated by Joinpoint regression analyses. Data with additional treatment fields of GI-NEN were extracted from the SEER-18 registry from 1 January 2010 to 31 December 2015. A total of 14 685 GI-NEN patients were included in this study. Statistical analyses were performed with SPSS 25.0, the Intercooled Stata SE 15.0, and GraphPad Prism 7.

Results: Incidence of GI-NENs increased from 0.51 per 100 000 patients in 1973 to 6.20 per 100 000 patients in 2015. Of them, 2003 patients were stage IV GI-NEN at the time of diagnosis, including 1459 (72.84%) patients with liver metastasis, 144 (7.19%) lung metastasis, 115 (5.74%) bone metastasis, and 27 (1.35%) brain metastasis. Esophageal NEN had the highest risk of metastasis (52.68%). The median survival for patients with liver, lung, bone, and brain metastasis was 38, 6, 9, and 2 months, respectively. The presence of lung or liver metastasis indicated higher risk of concurrent existence of bone and brain metastasis than those without.

Conclusion: Bone and brain metastasis should be screened in the GI-NEN patients if they had lung or liver metastasis. Findings of the current study could help clinicians to identify distant metastasis of GI-NENs as early as possible, and by which, to improve survival rate of GI-NENs.