Metastases from squamous cell carcinoma of the skin in southern Australia.

Background: The frequency with which squamous cell carcinoma (SCC) of the skin metastasizes is a matter of dispute. Studies from private practices have reported much lower rates than hospital-based surveys, and one school of thought is that SCCs which arise in sun-damaged skin have a low risk of metastasis.
Methods: A prospective study of out-patients with histologically confirmed SCC was undertaken in southern Australia, a region with a very high incidence of skin cancer.
Results: Between November 1988 and November 1989, 481 patients were entered into the study and 420 followed for at least 3 years. An SCC was the initial diagnosis for 73 patients, 3 were immunosuppressed and 2 had an SCC of the lip, leaving 68 immunocompetent patients with SCC of the skin. Metastatic SCC developed in 2 patients (5.8% adjusted for losses) within 3 years. The SCCs were small and arose in sun-damaged skin.
Conclusion: Patients with SCC of the skin need a careful follow-up because of the risk of metastasis.