Incidence and trends of basal cell carcinoma in Sweden: a population-based registry study.

ABSTRACT

BACKGROUND: Basal cell carcinoma (BCC) is the most common skin cancer. Incidence is largely unknown because of incomplete, or lack of, registration in most countries. OBJECTIVES: To assess current incidence rates and recent trends for BCC in the Swedish population. METHODS: Patient- and tumour-related features of all histologically confirmed BCC tumours diagnosed in Sweden from 2004 to 2017 were extracted from the population-based Swedish BCC Registry. Incidence rates were standardized to the 2013 European Standard Population and trends were analysed using Poisson regression models. RESULTS: The age-standardized person-based incidence rate of BCC in Sweden was 405 per 100 000 in 2017, rising from 308 per 100 000 in 2004, corresponding to an annual relative increase of 1·8% (women, 2·1%; men, 1·4%). Incidence was highest in elderly people and the most common tumour site was the head and neck. In 2017, the most common BCC subtypes were nodular and micronodular/infiltrative BCC (each 31%). Incidence of aggressive BCC subtypes increased faster than other subtypes. CONCLUSIONS: BCC incidence rates in Sweden are relatively high and increasing. The increasing trends were more pronounced in women and for aggressive BCC subtypes. What is already known about this topic? Basal cell carcinoma (BCC) is the most common skin cancer in white populations and its incidence is increasing. BCC is seldom registered in national population-based cancer registries, therefore incidence estimates are extrapolated from small studies or incomplete registers. BCC occurs more often in men than in women and occurs most commonly on the head and neck, followed by the trunk. What does this study add? This study provides current BCC incidence rates for an entire European population. Sex-specific trends show that BCC incidence is increasing faster in women in Sweden. Aggressive BCC subtypes appear to be increasing faster than other subtypes.