Objective: To determine the incidence of new skin cancer formation in
people who have had skin cancer removed. Study Design: A prospective s
tudy of Melbourne out-patients with histologically confirmed non-melan
oma 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. R
esults: Four hundred and eighty-one patients were entered and 420 foll
owed for at least 3 years. New NMSC developed in 60% (adjusted for los
ses) by the end of 3 years. A multivariate analysis determined that th
e main risk factor for new NMSC formation was the number of previous s
kin cancers that a patient had. These who had had multiple skin cancer
s (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 c
ancer formation. Conclusion: Patients with NMSC require long-term foll
owup because of the risk of new skin cancer formation, Those with mult
iple NMSC need more careful follow-up, and possibly more frequent exam
inations, because they are at greater risk.