Venous leg ulcers and squamous cell carcinoma: a large-scale epidemiological study.

In order to obtain a precise estimate of the relative risk of squamous cell carcinoma (SCC) in venous leg ulcers, we matched 10,913 patients with the diagnosis venous leg ulcer from the Swedish Inpatient Registry with registrations of SCC of the lower limb recorded by the Swedish Cancer Registry, and found 33 cases of non-melanoma skin cancer. After scrutinizing the pathology and case records, 17 cases of SCC were considered as being certainly secondary to venous leg ulcers, whereas in six cases of remitting/relapsing ulcers the connection was probable. The relative risk calculated on 17 cases was 5.80 (95% confidence interval = 3.08-9.29). The median duration of the ulcer before the diagnosis of cancer was 25 years. The mean follow-up time of the cohort was 8.5 years. We conclude that SCC is a complication of chronic venous leg ulcers, although the absolute risk is very small.