Objective: To determine the incidence of new skin cancer formation in people who have had skin cancer removed.
Study design: A prospective study of Melbourne out-patients with histologically confirmed non-melanoma skin cancer (NMSC). All patients with NMSC seen by one author (D.C.) between November 1988 and November 1989 were entered into the study and reviewed regularly. New skin cancers were removed and recorded.
Results: Four hundred and eighty-one patients were entered and 420 followed for at least 3 years. New NMSC developed in 60% (adjusted for losses) by the end of 3 years. A multivariate analysis determined that the main risk factor for new NMSC formation was the number of previous skin cancers that a patient had. Those who had had multiple skin cancers (3 or more) were at significantly greater risk than those with less than 3. Age, sex and type of NMSC were not risk factors for new skin cancer formation.
Conclusion: Patients with NMSC require long-term follow-up because of the risk of new skin cancer formation. Those with multiple NMSC need more careful follow-up, and possibly more frequent examinations, because they are at greater risk.