e21548 Background: Basosquamous carcinoma (BSC) is a rare cutaneous malignancy with histopathologic features of both basal and squamous cell carcinoma, accounting for 1. 2–2. 7% of basal cell carcinomas. BSC exhibits higher recurrence and metastasis rates than either subtype alone, reflecting its potential for aggressive clinical behavior. Clinical management is challenged by limited population-level data and reliance on small institutional series, highlighting the need for broader epidemiologic characterization of this tumor. To address this, the National Cancer Database (NCDB) was analyzed to reveal demographic, socioeconomic, and clinical patterns among patients diagnosed with BSC in the United States. Methods: A retrospective cohort study of the NCDB identified confirmed cases of BSC diagnosed from 2004–2020 (ICD-O-3 code 8094). Demographic and clinical variables (age, sex, race, ethnicity, primary site, stage, urban/rural residence, income, insurance status, facility type, treatment, and survival) were summarized using descriptive statistics, and incidence trends were assessed via regression analysis. Results: A total of 413 patients were diagnosed with BSC from 2004–2020. Incidence was stable over the study period (R² = 0. 97). The mean age at diagnosis was 67. 8 years (SD = 14. 3, range = 16–90 years), and the cohort was predominantly female (74. 8%), White (87. 2%), and non-Hispanic (90. 3%). Most patients were Medicare-insured (55. 9%) and treated at community (40. 1%) or academic (35. 4%) facilities. Patients primarily resided in metropolitan areas (85. 2%) and were in the highest income quartile (≥74, 063; 36. 0%). The most common primary sites were the vulva (37. 0%), anal canal (12. 3%), and anus (11. 4%). Stage I disease predominated (36. 3%), and mean tumor size was 34 mm. Surgery was the primary treatment (70. 0%), with negative margins achieved in 55. 0% of those cases. Radiation was administered in 34. 9% and chemotherapy in 30. 5% of cases. Two-, five-, and ten-year survival rates were 83. 1%, 66. 6%, and 44. 1%, respectively, with mean survival of 114 months. Conclusions: To our knowledge, this is the first NCDB analysis of BSC, addressing an important gap in national epidemiologic data for this malignancy. BSC primarily affects older, non-Hispanic White females, is treated at community or academic centers, and typically presents at an early stage. Although HPV is a known driver of squamous cell carcinoma, no evidence currently links HPV to BSC, despite the anogenital distribution observed. Socioeconomic patterns, including the concentration of patients in metropolitan areas and the highest income quartile, may reflect structural factors affecting disease recognition and access to specialized care. Further research is needed to clarify how demographic and socioeconomic factors shape diagnosis, treatment patterns, and long-term outcomes in this rare but clinically significant malignancy.
Saglimbeni et al. (Thu,) studied this question.