INTRODUCTION
Basal cell carcinoma (BCC) is a locally invasive malignant skin tumor. It is the commonest cancer diagnosed in the United States.1 Its incidence is rising. Several population-based studies note an alarming increase in the overall incidence of BCC over the past several decades.2-4Alfred W. Kopf’s original characterization in 1979 of the histological subtypes of BCCs using data from approximately 3,500 patients reported that 85% occur on the head and neck.5 Subsequent population-based studies corroborate a majority of BCCs occurring on the head and neck region,2,3,6,7 though these studies do not assess age as an independent risk factor for the localization of BCCs.Population-based studies from Europe, Asia, and the United States report conflicting data regarding gender discrepancies in the incidence of BCC.8 Whereas many studies reporting sex-specific incidence rates (IR) of BCC demonstrate higher IRs in males,8,9 Christenson et al reported a significantly higher IR of BCC in the female population, notably in those younger than 40 years.4 In this population-based retrospective incidence case review of patients from the Rochester Epidemiology Project, they reported a significant increase in the incidence of BCC during the study period 1976-2003, accounted for by an increase in incidence in women, but not in men. A majority of these tumors were located on the head and neck, most commonly in the central face; 10.12% were located at the forehead and temple amongst women, while 23.20% were located at the forehead and temple amongst men. Our data also suggest men have a higher likelihood of developing BCC at the temple.Using data from the population-based New Hampshire Skin Cancer Study, Barton et al recently reported that patients with early-onset BCC (in their study, 50 years or younger) were more likely to be women, and that early-onset BCC was more likely to occur on the head and neck.1 They also reported that early-onset BCC was more likely to be of an aggressive histological subtype (infiltrative, sclerosing, morpheaform, and micronodular), which corroborates previous findings by Leffell et al.10 These reports seem to at least partially dispel the notion that the rising incidence of BCC could be solely driven by an increase in utilization of healthcare and improved patient education on skin malignancies; and suggest there may be an inherent difference in the natural history and pathogenesis of BCCs in the younger population.While others have suggested BCCs in patients younger than 40 years tend to occur in females,1,4,11 we have specifically noted a number of young female patients presenting with forehead BCCs. The goal of our study was to evaluate whether there exists age- or gender-related relationships in the location of BCCs, specifically at the forehead and its subunits (forehead proper, temple, suprabrow, and glabella). We also tested our a priori hypothesis that young females develop BCCs on the forehead at a higher rate than do other demographic groups.
