Descriptive epidemiology of pituitary tumors in the United States, 2004–2009
Authors: Gittleman Haley , Ostrom Quinn T. , Farah Paul D. , Ondracek Annie , Chen Yanwen , Wolinsky Yingli , Kruchko Carol , Singer Justin , Kshettry Varun R. , Laws Edward R. , Sloan Andrew E. , Selman Warren R. , Barnholtz-Sloan Jill S. 
Published: June 2014

Object
Pituitary tumors are abnormal growths that develop in the pituitary gland. The Central Brain Tumor Registry of the United States (CBTRUS) contains the largest aggregation of population-based data on the incidence of primary CNS tumors in the US. These data were used to determine the incidence of tumors of the pituitary and associated trends between 2004 and 2009.

Methods
Using incidence data from 49 population-based state cancer registries, 2004–2009, age-adjusted incidence rates per 100,000 population for pituitary tumors with ICD-O-3 (International Classification of Diseases for Oncology, Third Edition) histology codes 8040, 8140, 8146, 8246, 8260, 8270, 8271, 8272, 8280, 8281, 8290, 8300, 8310, 8323, 9492 (site C75.1 only), and 9582 were calculated overall and by patient sex, race, Hispanic ethnicity, and age at diagnosis. Corresponding annual percent change (APC) scores and 95% confidence intervals were also calculated using Joinpoint to characterize trends in incidence rates over time. Diagnostic confirmation by subregion of the US was also examined.

Results
The overall annual incidence rate increased from 2.52 (95% CI 2.46–2.58) in 2004 to 3.13 (95% CI 3.07–3.20) in 2009. Associated time trend yielded an APC of 4.25% (95% CI 2.91%–5.61%). When stratifying by patient sex, the annual incidence rate increased from 2.42 (95% CI 2.33–2.50) to 2.94 (95% CI 2.85–3.03) in men and 2.70 (95% CI 2.62–2.79) to 3.40 (95% CI 3.31–3.49) in women, with APCs of 4.35% (95% CI 3.21%–5.51%) and 4.34% (95% CI 2.23%–6.49%), respectively. When stratifying by race, the annual incidence rate increased from 2.31 (95% CI 2.25–2.37) to 2.81 (95% CI 2.74–2.88) in whites, 3.99 (95% CI 3.77–4.23) to 5.31 (95% CI 5.06–5.56) in blacks, 1.77 (95% CI 1.26–2.42) to 2.52 (95% CI 1.96–3.19) in American Indians or Alaska Natives, and 1.86 (95% CI 1.62–2.13) to 2.03 (95% CI 1.80–2.28) in Asians or Pacific Islanders, with APCs of 3.91% (95% CI 2.88%–4.95%), 5.25% (95% CI 3.19%–7.36%), 5.31% (95% CI –0.11% to 11.03%), and 2.40% (95% CI –3.20% to 8.31%), respectively. When stratifying by Hispanic ethnicity, the annual incidence rate increased from 2.46 (95% CI 2.40–2.52) to 3.03 (95% CI 2.97–3.10) in non-Hispanics and 3.12 (95% CI 2.91–3.34) to 4.01 (95% CI 3.80–4.24) in Hispanics, with APCs of 4.15% (95% CI 2.67%–5.65%) and 5.01% (95% CI 4.42%–5.60%), respectively. When stratifying by age at diagnosis, the incidence of pituitary tumor was highest for those 65–74 years old and lowest for those 15–24 years old, with corresponding overall age-adjusted incidence rates of 6.39 (95% CI 6.24–6.54) and 1.56 (95% CI 1.51–1.61), respectively.

Conclusions
In this large patient cohort, the incidence of pituitary tumors reported between 2004 and 2009 was found to increase. Possible explanations for this increase include changes in documentation, changes in the diagnosis and registration of these tumors, improved diagnostics, improved data collection, increased awareness of pituitary diseases among physicians and the public, longer life expectancies, and/or an actual increase in the incidence of these tumors in the US population.