Background: The frequency with which squamous cell carcinoma (SCC) of
the skin metastasizes is a matter of dispute. Studies from private pra
ctices have reported much lower rates than hospital-based surveys, and
one school of thought is that SCCs which arise in sun-damaged skin ha
ve a low risk of metastasis. Methods: A prospective study of out-patie
nts with histologically confirmed SCC was undertaken in southern Austr
alia, a region with a very high incidence of skin cancer. Results: Bet
ween November 1988 and November 1989, 481 patients were entered into t
he 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 o
f the lip, leaving 68 immunocompetent patients with SCC of the skin. M
etastatic SCC developed in 2 patients (5.8% adjusted for losses) withi
n 3 years. The SCCs were small and arose in sun-damaged skin. Conclusi
on: Patients with SCC of the skin need a careful follow-up because of
the risk of metastasis.