Nonmelanoma skin cancer in northern Finland

The incidence of nonmelanoma skin cancers is highest in those geographic areas where light-skinned people are exposed to large amounts of sunlight. The purpose of this study was to detect differences in nonmelanoma skin cancers diagnosed in Northern Finland compared to those from elsewhere. Another purpose was to estimate whether changes have occurred in clinical diagnosis, site distribution, and recurrence rate during the past 15 years.

The material included patients treated at Oulu University Hospital in Northern Finland (64.6 degrees N) during the years 1976-1977 and 1991-1992. Information was collected from files on 334 patients with 428 different, histologically verified skin cancers.

In 1976-1977, the average age of men with basal cell carcinoma (BCC) was 61 years, whereas the women's average age was 66 years. In 1991-1992, the corresponding ages were 69 and 72 years. The site distribution did not show any obvious changes in the 15 years, but the differences between sexes had become more prominent. Men had more BCC on the ears and the trunk, whereas women had more BCC on the nose and the forehead. Most of the squamous cell carcinomas (SCC) were on the head and neck similar to BCC, but on the ears of men there occurred relatively more SCC than BCC.

The clinical diagnosis of BCC was fairly easy to make, whereas that of SCC seemed to be very difficult clinically and was only correct in 10% of the cases. The markedly decreased recurrence rate of BCC between 1976 and 1992 probably occurred because of changes in treatment practices.