Approximately 2 million basal cell carcinomas occur in the United States each year, a number that has increased only modestly during the past 15 years, according to a report published online June 3 in JAMA Dermatology.
The epidemiology of BCCs has been difficult to pin down because these tumors are excluded from cancer registries and national cancer surveillance programs, and because when they are tracked they are usually lumped together with squamous cell carcinomas. The most recent National Cancer Institute–funded survey of BCC was done more than 30 years ago.
©Kelly Nelson/National Cancer Institute
So the current incidence of BCC “is not well characterized.” Nevertheless. some researchers have posited that the incidence has risen 80%-200% during the past 10-20 years, said Dr. Maryam M. Asgari of Kaiser Permanente Northern California, Oakland, and the department of dermatology at the University of California, San Francisco.
To estimate incidence more accurately, Dr. Asgari and her associates analyzed data from every electronic pathology report in a registry covering the 3.2 million participants in the HMO from 1998 through 2012. They identified 221,624 cases of BCC in patients aged 2-105 years. The annual incidence increased from 513 to 600 cases per 100,000 population during the study period – a 17% rise that was deemed “not remarkable.”
“In extrapolating our data to the United States, we estimate that approximately 2 million individuals develop at least one BCC in the U.S. in a given year,” Dr. Asgari and her associates wrote (JAMA Dermatol. 2015 June 3 [doi:10.1001/jamadermatol.2015.1188]).
This total is higher than that cited on the National Institutes of Health website, which estimates the annual incidence of all nonmelanoma skin cancers, not just BCC, at 2 million per year.
Males were at higher risk than were females for developing BCC (incidence rate ratio, 1.65), and risk increased with increasing patient age. As expected, whites were at 8- to 70-fold greater risk than were Hispanics, Asians, or blacks. Contrary to one previous report, the incidence of BCC did not increase among Hispanics during the study period.
The National Cancer Institute and the National Institutes of Health supported the study. Dr. Asgari reported receiving research grants from Kaiser Permanente, Pfizer, and Valeant Pharmaceuticals, but not for this project.