Incidence of Neuroendocrine Tumors Among All Cancer Types
Neuroendocrine tumors (NETs) account for approximately 2% of all malignancies in the United States, with an overall incidence that has risen dramatically to 5.25-6.98 per 100,000 population per year. 1, 2
Overall Incidence and Prevalence
The crude incidence of NETs increased significantly from 3.0 cases per 100,000 per year in earlier decades to 5.25 per 100,000 per year by 2004, representing a 6.4-fold increase from 1973 (1.09 per 100,000) to 2012 (6.98 per 100,000). 1, 2
The prevalence of NETs has been calculated at 35 per 100,000 population per year, with an estimated 171,321 individuals living with NETs in the United States as of January 1,2014. 1, 2
NETs represent approximately 2% of all cancer cases diagnosed in the United States. 3
Site-Specific Distribution
Gastrointestinal and Pancreatic NETs (approximately 67% of all NETs):
- Small intestinal NETs: 0.95 per 100,000 per year 1
- Rectal NETs: 0.86 per 100,000 per year 1
- Appendiceal NETs: 35% of all NETs 1
- Pancreatic NETs: 0.32 per 100,000 per year (representing 5% of all NETs) 1
- Gastric NETs: 0.30 per 100,000 per year (representing 3% of all NETs), with incidence increasing from 0.31 per 1,000 in 1975 to 4.85 per 1,000 in 2014 1, 4
- Duodenal NETs: 3% of all NETs 1
Respiratory Tract NETs (approximately 25% of all NETs):
- Lung NETs: 15% of all NETs, with a combined incidence of 1.57 per 100,000 inhabitants 1
- Typical carcinoids comprise 1-2% of all pulmonary neoplasms 1
- Atypical carcinoids comprise only 0.1-0.2% of pulmonary neoplasms 1
- Small-cell lung cancer (SCLC), the most common bronchial NET, accounts for 15-20% of invasive lung cancers 1
Other Sites:
- Thymic NETs: approximately 3% of all NETs, with an incidence of 0.02 per 100,000 population per year 1
- Rectal NETs: 10% of all NETs 1
- Colon NETs: 7% of all NETs (4% right colon, 3% left colon) 1
Important Clinical Context
The rising incidence is primarily attributed to improved detection methods and diagnostic protocols rather than true increases in disease occurrence:
- Enhanced imaging techniques, particularly somatostatin receptor imaging, are detecting smaller, earlier-stage tumors that would have been missed previously. 5
- Meticulous autopsy studies have identified pancreatic NETs in up to 10% of individuals, indicating that the true burden of disease far exceeds clinically diagnosed cases. 1
- The autopsy incidence of pituitary NETs is 8.4 per 100,000 per year, significantly higher than the clinical incidence of 3.0-5.25 per 100,000, demonstrating substantial underdiagnosis during life. 6
Survival has improved significantly over time:
- Five-year overall survival for all NETs improved from 62.8% for cases diagnosed between 1973-1982 to 86.7% for cases diagnosed between 2003-2012. 4
- The hazard ratio for mortality decreased from 2000-2004 to 2009-2012 (HR 0.79,95% CI 0.73-0.85), with even larger improvements noted in distant-stage gastrointestinal NETs (HR 0.71) and pancreatic NETs (HR 0.56). 2