Basal cell carcinoma. An epidemiologic study in a defined population.

BACKGROUND. The incidence of basal cell carcinoma (BCC) in a defined population is unknown. METHODS. The incidence of histologically diagnosed cases of BCC in a defined population of a city in southern Sweden was studied. Four 2-year periods were examined from 1970 to 1986. Cases from 1970 and 1980 were reexamined microscopically. RESULTS. From 1970 to 1986, the age-standardized incidence of BCC was doubled. BCC was equally common in male and female patients. It was possible to trace another BCC in the medical history of 41% of the patients. The risk of development of BCC increased rapidly with age greater than 55 years. Approximately two-thirds of the tumors were found in the head and neck region. There was a possible increase in superficial multicentric tumors on the trunk but otherwise an essentially unchanged pattern in type and distribution. CONCLUSIONS. The age-standardized incidence of histologically diagnosed BCC was doubled from 1970 to 1986. The rapid increase should be taken into consideration when planning allocation of medical resources.