Smoking, alcohol and family history of cancer as risk factors for small intestinal neuroendocrine tumors: a systematic review and meta-analysis

Abstract

Objectives: Risk factors for small intestinal neuroendocrine tumors (SI-NETs) are not well understood. The aim of this systematic literature review was to identify risk factors for SI-NET and to further assess these by meta-analysis.

Material and methods: PubMed and abstracts from the ENETS and NANETS were searched for studies published until May 2015. Eligible studies were selected according to the PRISMA statement.

Results: Seven studies evaluating six individual populations were included (study accrual period 1980–2012) in the meta-analysis, involving 765 (range 17–325) cases and 502,282 (range 52–498,376) controls. All studies were case–control by design. The following risk factors were reported in ≥2 studies: family history of any cancer, family history of colorectal cancer, ever alcohol use and ever smoking. The pooled OR was 1.34 (95% CI: 1.12–1.60; p < .01; I² = 0.0%) for family history of any cancer, 1.43 (95% CI: 1.15–1.79; p < .01; I² = 0.0%) for family history of colorectal cancer, 1.04 (95% CI: 0.63–1.72; p = .87; I² = 65.0%) for ever alcohol use and 1.40 (95% CI: 1.06–1.86; p < .05; I² = 49.3%) for ever smoking.

Conclusions: Family history of any cancer, family history of colorectal cancer and history of ever smoking were associated with an increased risk of SI-NET by meta-analysis. Alcohol consumption was not a significant risk factor for SI-NET. However, the studies reporting smoking and alcohol had a high degree of heterogeneity. Therefore, further studies are needed for clarification of smoking and alcohol as risk factors for the occurrence of SI-NET.

Keywords:

• SI-NET
• NET
• small intestinal neuroendocrine tumor
• epidemiology
• meta-analysis
• risk factor

Acknowledgements

This study was conducted through Pancreas 2000, which is a European educational and scientific pancreatology program initiated by the Karolinska Institute in Stockholm, Sweden, and the European Pancreatic Club.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.