Basal cell and squamous cell carcinomas are important risk factors for cutaneous malignant melanoma. Screening implications.

BACKGROUND

This study was designed to determine the risk of developing malignant melanoma (MM) in patients with a history of basal cell and/or squamous cell skin cancer (BCC/SCC) and to determine whether surveillance efforts can be directed toward these patients for the detection of early MMs.

METHODS

The study cohort was followed by annual total cutaneous examination (TCE). Controls consisted of individuals from the United States population matched for age, sex, and length of follow-up. The anatomic locations of the study cohorts' newly diagnosed MMs were plotted on an anatomic chart. The setting was a private dermatology practice. Two hundred, ninety consecutive white patients with a history of BCC/SCC but with no personal or family history of MM were followed by annual TCEs. The main outcome measures were the relative risk of developing MM and their prognosis.

RESULTS

Ten of the 290 patients developed an MM within an average of 109 months of follow-up (range, 3-17 years). All MMs were less than 0.70 mm in Breslow thickness and 80% occurred on usually clothed cutaneous sites. The expected number of MMs in the control population was 0.59 (P = 0.006), resulting in a relative risk of 17.

CONCLUSION

Patients with BCC/SCC skin cancer are at substantial increased risk for developing MM. Regular and life-long surveillance TCE is an inexpensive and effective method for detecting curable MMs in such patients.