Association between somatostatin analogues and diabetes mellitus in gastroenteropancreatic neuroendocrine tumor patients: A Surveillance, Epidemiology, and End Results-Medicare analysis of 5235 patients

Background Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are increasingly common malignancies and tend to have favorable long-term prognoses. Somatostatin analogues (SSA) are a first-line treatment for many NETs. Short-term experiments suggest an association between SSAs and hyperglycemia. However, it is unknown whether there is a relationship between SSAs and clinically significant hyperglycemia causing development of diabetes mellitus (DM), a chronic condition with significant morbidity and mortality. Aim In this study, we aimed to compare risk of developing DM in patients treated with SSA vs no SSA treatment. Methods and Results Using the Surveillance, Epidemiology, and End Results (SEER) database and linked Medicare claims (1991-2016), we identified patients age 65+ with no prior DM diagnosis and a GEP-NET in the stomach, small intestine, appendix, colon, rectum, or pancreas. We used chi(2) tests to compare SSA-treated and SSA-untreated patients and multivariable Cox regression to assess risk factors for developing DM. Among 8464 GEP-NET patients, 5235 patients had no prior DM and were included for analysis. Of these, 784 (15%) patients received SSAs. In multivariable analysis, the hazard ratio of developing DM with SSA treatment was 1.19, which was not statistically significant (95% CI 0.95-1.49). Significant risk factors for DM included black race, Hispanic ethnicity, prior pancreatic surgery, prior chemotherapy, tumor size >2 cm, pancreas tumors, and higher Charlson scores. Conclusion DM was very common in GEP-NET patients, affecting 53% of our cohort. Despite prior studies suggesting an association between SSAs and hyperglycemia, our analysis found similar risk of DM in SSA-treated and SSA-untreated GEP-NET patients. Further studies are needed to better understand this relationship. As NET patients have increasingly prolonged survival, it is crucial to identify chronic conditions such as DM that these patients may be at elevated risk for.