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

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.