What is the incidence of pituitary neuroendocrine tumors (PitNETs) among all other cancer types?

Incidence of Pituitary Neuroendocrine Tumors Among All Cancers

Pituitary neuroendocrine tumors (PitNETs) have a clinical incidence of approximately 3.0-5.25 cases per 100,000 population per year, making them relatively uncommon compared to most other cancer types, though they represent the third most frequently diagnosed intracranial tumor. 1, 2

Comparative Incidence Data

Overall Cancer Context

• PitNETs account for approximately 1-4 cases per 100,000 population annually in clinical practice, though autopsy studies reveal a much higher incidence of 8.4 per 100,000 per year, indicating substantial underdiagnosis during life 1, 3
• For comparison, the overall neuroendocrine tumor (NET) incidence across all sites is 5.25 per 100,000 per year, meaning pituitary NETs represent a similar or slightly lower incidence than the combined rate of all other NET sites 4, 3

Age-Specific Patterns

• In pediatric populations, PitNETs are rare, representing only 1% of all intracranial neoplasms before age 15 years 5, 1
• This increases dramatically to 18% of intracranial neoplasms in patients aged 15-24 years 5, 1
• PitNETs constitute 78% of pituitary fossa lesions in children and young people overall 5, 1
• The highest incidence occurs from the fifth decade onwards in adults 1

Comparison to Other Neuroendocrine Tumor Sites

PitNETs have comparable or higher incidence than many other NET sites:

• Small intestinal NETs: 0.95 per 100,000 per year 3
• Rectal NETs: 0.86 per 100,000 per year 3
• Pancreatic NETs: 0.32 per 100,000 per year (representing 5% of all NETs) 5, 3
• Gastric NETs: 0.30 per 100,000 per year 3
• Lung NETs: 1.57 per 100,000 per year (15% of all NETs) 3

Important Clinical Caveats

Detection Discrepancy

• Meticulous autopsy studies have identified pancreatic NETs in up to 10% of individuals, far exceeding clinically diagnosed cases, and a similar pattern exists for pituitary tumors 5, 3
• The autopsy incidence is 2-3 times higher than clinical incidence, demonstrating that many PitNETs remain asymptomatic and undetected throughout life 1, 3

Familial Syndromes

• In Multiple Endocrine Neoplasia Type 1 (MEN1), PitNETs occur in 30-55% of affected patients, predominantly as prolactinomas, making them one of the three major manifestations alongside parathyroid and pancreatic tumors 5
• The prevalence of MEN1 is estimated at 1:20,000-40,000, with PitNETs representing less than 5% of pituitary tumors in this syndrome 5
• Approximately 5% of all PitNETs occur in hereditary or familial contexts 6

Functional Classification

• Nonfunctioning PitNETs account for 30% of all pituitary tumors and represent the most common type of macroadenomas 2
• These tumors are often diagnosed later due to lack of hormonal symptoms, typically presenting with mass effects rather than endocrine syndromes 2