Leg ulcers and squamous cell carcinoma. An epidemiological study and a review of the literature.

There has been concern about the possible risk of malignification of venous leg ulcers. To investigate the incidence of squamous cell carcinoma in venous ulcers, data on 1,170 patients with venous leg ulcers and 511 patients with other types of non-traumatic ulcers were matched with corresponding data from the Swedish Cancer Registry to determine the incidence of squamous cell carcinoma in these patients. Mean follow-up time was 8.3 years. Seven cases of squamous cell cancer were observed, while the expected number was 10.56 (relative risk = 0.66; 95% confidence interval = 0.27 to 1.36). However, four of the observed cancers were located on the lower leg in venous ulcers, the expected number being 0.68 (relative risk = 5.89; 95% confidence interval = 1.60 to 15.08). This indicates that a certain alertness is necessary when treating this common disease. The literature on cancer in venous ulcers, where 152 cases of squamous cell carcinoma in venous ulcers are reported, is reviewed.