Background
Many international studies have observed an increase in the incidence rates of small intestinal (SI) neuroendocrine tumours (NETs), although the absolute incidence rates vary between countries. This retrospective population-based analysis examines overall incidence trends and separates Queensland patients who present with node-negative, node-positive or metastatic disease at diagnosis to determine whether survival is improving.
Methods
Data on Queensland patients diagnosed with SI NETs between 2001 and 2015 were sourced from the Queensland Oncology Repository. Staging algorithms developed by QCCAT, utilising pathology and admissions data to calculate stage at diagnosis, formed the basis for this analysis. Stage is reported as localised, regional (node-positive) or metastatic disease.
Results
777 SI NETs were diagnosed between 2001 and 2015. The incidence of SI NETs has doubled from 0.7 cases to 1.4 cases per 100,000 over the 15-year period. SI NETs were most commonly diagnosed in the ileum 49% and carcinoid histology comprised of 83% of all cases. 30% of SI NETs presented with nodal involvement at diagnosis and a further 20% with distant metastasis.
Median age for SI NET patients was 65, and 57% were male. Patients with distant disease were more likely to be from regional and remote areas of Queensland (39%) than those with localised disease (24%).
Five-year survival for all patients diagnosed 2011-2015 was 84%, increasing from 74% during 2001-2005. Survival was lowest for those with metastatic disease (62%). Patients with localised or regional disease displayed similar five-year survival (loc: 86% [CI 81%-91%], reg: 90% [CI 85%-96%]). Survival increased between 2001-2005 and 2011-2015 for each stage of disease.
Conclusions
The incidence of SI NETs in Queensland has doubled over the last 15 years. Survival for patients with all stages of SI NETs at diagnosis has improved in recent years, consistent with other studies reported worldwide.