In a recent study of a northern California population, researchers identified several geographic clusters with modestly elevated incidence of basal cell carcinoma (BCC). Researchers used a BCC registry to determine rates of BCC by census block group, and used spatial scan statistics to identify statistically significant geographic clusters of BCCs, adjusting for age, sex, and socioeconomic factors. They found:

• Spatial analysis of 28,408 individuals who received a diagnosis of at least 1 BCC in 2011 or 2012 revealed distinct geographic areas with elevated BCC rates.

• Among the 14 counties studied, BCC incidence ranged from 661 to 1,598 per 100,000 person-years.

• After adjustment for age, sex, and neighborhood socioeconomic status, a pattern of 5 discrete geographic clusters emerged, with a relative risk ranging from 1.12 for a cluster in eastern Sonoma and northern Napa counties, to 1.40 for a cluster in east Contra Costa and west San Joaquin counties, compared to persons residing outside that cluster.

Citation: Ray GT, Kulldorff M, Asgari MM. Geographic clusters of basal cell carcinoma in a northern California health plan population. [Published online ahead of print July 20, 2016]. JAMA Dermatol. doi:10.1001/jamadermatol.2016.2536.