Trends in Basal Cell Carcinoma Incidence and Identification of High-Risk Subgroups, 1998-2012

IMPORTANCE: The incidence of basal cell carcinomas (BCCs) is increasing globally, but incidence rates in the United States are difficult to quantify because BCCs are not reportable tumors. OBJECTIVE: To estimate annual BCC incidence rates by age, sex, and race/ethnicity to identify demographically distinct high-risk subgroups and to assess changes in rates over time. DESIGN, SETTING, AND PARTICIPANTS: In this retrospective cohort study (January 1, 1998, through December 31, 2012), we studied 147 093 patients with BCC from Kaiser Permanente Northern California, a large, integrated health care provision system, identified using a previously validated BCC registry. MAIN OUTCOMES AND MEASURES: We estimated annual BCC incidence rates by age, sex, and race/ethnicity and assessed changes in rates over time. The BCC incidence rates were standardized to the age, sex, and race/ethnicity distribution of the 2010 US Census population. RESULTS: In models adjusting for age, sex, and race, male patients had higher rates than female patients (incidence rate ratio IRR, 1.65; 95% CI, 1.60-1.70). Persons 65 through 79 years of age and those 80 years and older had higher rates than persons 40 through 64 years of age (IRR, 2.96; 95% CI, 2.86-3.06; and IRR, 5.14; 95% CI, 4.94-5.35, respectively). Whites had higher rates than multiracial persons (IRR, 1.96; 95% CI, 1.80-2.13), Hispanics (IRR, 8.56; 95% CI, 7.79-9.41), Asians (IRR, 33.13; 95% CI, 27.84-39.42), and blacks (IRR, 72.98; 95% CI, 49.21-108.22). CONCLUSIONS AND RELEVANCE: We estimate that BCCs occur in approximately 2 million Americans annually. Our findings provide an updated estimate of the incidence of BCCs, highlight the changing epidemiologic findings, and better identify demographically distinct high-risk subgroups.