Epidemiology of malignant cutaneous granular cell tumors: A US population-based cohort analysis using the Surveillance, Epidemiology, and End Results (SEER) database.

BACKGROUND: Malignant cutaneous granular cell tumors (mcGCTs) are rare and associated with substantial morbidity and mortality. The literature includes single-institution studies.

OBJECTIVE: To examine the incidence, secondary malignancies, treatment, overall survival, and disease-specific survival (DSS) of patients with mcGCT.

METHODS: A population-based cohort analysis was conducted in the Surveillance, Epidemiology, and End Results database from 1973 to 2013 for patients with a diagnosis of mcGCT. Risk-adjusted associations between overall survival/DSS and patient characteristics and treatment modalities were assessed by Cox proportional hazard regression. Quantile regression was used to determine median survival times.

RESULTS: The 5-year DSS rate was 62.8%. Patients demonstrated an increased risk for renal and pancreatic cancers. In risk-adjusted models, male sex (hazard ratio [HR], 0.21; 95% confidence interval [CI], 0.06-0.82; P = .02), advanced cancer stage (HR, 2.29; 95% CI, 1.40-3.72; P < .01), and surgical resection (HR, 0.06; 95% CI, 0.01-0.59; P = .02) predicted DSS. Median survival time in years increased for males (1.39), earlier stage (0.60), and surgical intervention (5.34).

LIMITATIONS: Absent or incorrect reporting in retrospective Surveillance, Epidemiology, and End Results data is possible. The database is more likely to include academic centers. Some subanalyses may be underpowered because of the limited sample size for a rare cancer.

CONCLUSIONS: Our study presents an in-depth assessment of factors that identify high-risk patients. Residency in a nonmetro area, black race, female sex, and no surgical resection were each associated with poorer DSS.