Pituitary Adenoma Incidence, Management Trends, and Long-term Outcomes: A 30-Year Population-Based Analysis

Abstract

Objective: To perform a population-based study of pituitary adenoma epidemiology, including longitudinal trends in disease incidence, treatment patterns, and outcomes.

Patients and methods: In this study of incident pituitary adenomas in Olmsted County, Minnesota, from January 1, 1989, through December 31, 2019, we identified 785 patients who underwent primary screening, 435 of whom were confirmed as harboring incident pituitary adenomas and were included. Primary outcomes of interest included demographic characteristics, presenting features, and disease outcomes (tumor control, biochemical control, and complications).

Results: Among our 435 study patients, 438 unique pituitary adenomas were diagnosed at a median patient age of 39 years (interquartile range [IQR], 27 to 58 years). Adenomas were incidentally identified in 164 of the 438 tumors (37%). Common symptomatic presentations included hyperprolactinemia (188 of 438 [43%]) and visual field deficit (47 of 438 [11%]). Laboratory tests confirmed pituitary hormone hypersecretion in 238 of the 435 patients (55%), which was symptomatic in 222. The median tumor diameter was 8 mm (IQR, 5 to 17 mm). Primary management strategies were observation (156 of 438 tumors [36%]), medication (162 of 438 tumors [37%]), and transsphenoidal resection (120 of 438 tumors [27%]). Tumor and biochemical control were achieved in 398 (95%) and 216 (91%) secreting tumors, respectively. New posttreatment pituitary or visual deficits were noted in 43 (11%) and 8 (2%); apoplexy occurred in 28 (6%). Median clinical follow-up was 98 months (IQR, 47 to 189 months). Standardized incidence rates were 3.77 to 16.87 per 100,000 population, demonstrating linear expansion over time (R²=0.67). The mean overall standardized incidence rate was 10.1 per 100,000 population; final point prevalence was 175.1 per 100,000 population.

Conclusion: Pituitary adenoma is a highly incident disease, with prolactin-secreting and incidental lesions representing the majority of tumors. Incidence rates and asymptomatic detection appear to be increasing over time. Presenting symptoms and treatment pathways are variable; however, most patients achieve favorable outcomes with observation or a single treatment modality.

FIGURE 1.

Standardized incidence rates of pituitary adenoma (green bars) and brain magnetic resonance imaging (MRI) studies (blue line) in Olmsted County, Minnesota, during 1989–2019 showing an overall increase in disease burden and MRI utilization across the study period.

FIGURE 2.

A, Incident case distribution by symptomatic or incidental mode of presentation, grouped by 5-year interval. B, Area chart depicting the relative fractions of pituitary adenoma subtypes contributing to the overall standardized incidence rate for incident cases in Olmsted County, Minnesota, during the 1989–2019 study period. Diagnoses represented by increasing proportional representation included Cushing disease (green), acromegaly (blue), prolactinoma (brown), and nonfunctioning adenoma (NFA; yellow). C, Differential treatment interventions, with bars representing sequential lines of therapy. Bar segments correspond to the fractions of patients receiving a given modality as a percentage of all patients requiring that line of therapy. Numbers within bars represent the total sample size of patients receiving that treatment at that line of therapy. RT, radiotherapy; Rx, medical management; SRS, stereotactic radiosurgery; TSR, transsphenoidal resection.

FIGURE 3.

Flowchart of treatment pathways. obs, observation; Rx, medical management; SRS, stereotactic radiosurgery; TSR, transsphenoidal resection.