Epidemiologic trends in neuroendocrine tumors: An examination of incidence rates and survival of specific patient subgroups over the past 20 years.

Introduction: Neuroendocrine tumors (NETs) represent a small proportion of cancers, but are increasing in incidence due to incidental diagnosis. We examined NET incidence and survival over time in a population-based registry.

Materials/methods: We identified all NET cases diagnosed between 1995 and 2014 in the Surveillance, Epidemiology, and End Results database, November 2016 submission. We determined incidence rates and calculated overall and cancer-specific survival curves in different subgroups stratified by grade, stage, and age at diagnosis.

Results: We identified 85,133 patients with a diagnosis of NET between 1995 and 2014. Patients with grade 1, localized NETs had the best median overall survival (233 months, 95% confidence intervals [CI] not estimable) and 5-year cancer-specific survival (97.6%; 95% CI, 97.4%, 97.8%). The median overall survival decreased with age across the entire spectrum of ages, with patients >70 years having a particularly poor prognosis (28.0 months; 95% CI, 26.5, 29.5). Patients >70 years old often had distant (34.3%) or grade 3 disease (40.8%), but even elderly patients with lower grade and/or stage disease had worse median overall survival compared with younger subjects.

Conclusions: Age appears to be associated with a worse prognosis independent of NET stage, and grade at the time of diagnosis. Patients with grade 1, localized NETs have an excellent long-term prognosis. Further research is warranted on reducing intensity of surveillance in these patients.