Tracking Pleomorphic Adenoma Incidence Trends Over 47 Years: A Population-Based Study

Area of Science:

• Otolaryngology
• Head and Neck Surgery
• Epidemiology

Background:

• Pleomorphic adenomas (PAs) are the most common benign salivary gland neoplasms.
• Understanding long-term trends in PA incidence and clinical presentation is crucial for resource allocation and patient management.

Purpose of the Study:

• To track the incidence of pleomorphic adenomas (PAs) over five decades in Olmsted County, Minnesota.
• To compare demographic and treatment trends associated with PAs during this period.

Main Methods:

• Retrospective cohort study of patients with pathologically diagnosed nonrecurrent pleomorphic adenomas from 1976 to 2022.
• Incidence calculated per 100,000 person-years, age- and sex-adjusted to US 2020 census data.
• Statistical analysis included Poisson rate regression, Spearman rank correlation, Wilcoxon rank sum, and Kruskal-Wallis tests.

Main Results:

• A total of 251 patients with PA were identified, with a median age of 50.0 years and slight female predominance.
• Adjusted incidence increased from 2.50/100,000 person-years (1976-1979) to 5.73/100,000 person-years (2020-2022).
• Less extensive surgeries increased, while total parotidectomies decreased; incidental imaging findings and age at diagnosis also rose.

Conclusions:

• The incidence of pleomorphic adenomas in Olmsted County is higher than previously reported US estimates and has significantly increased.
• Shifting trends include a higher proportion of incidental diagnoses, increased age at diagnosis, and a move towards less invasive surgical approaches.
• These changes reflect advancements in imaging technology and an aging population seeking treatment for benign parotid masses.