Diagnosis and management of malignant melanoma

The incidence of malignant melanoma has increased in recent years more than that of any other cancer in the United States. About one in 70 people will develop melanoma during their lifetime. Family physicians should be aware that a patient with a changing mole, an atypical mole or multiple nevi is at considerable risk for developing melanoma. Any mole that is suggestive of melanoma requires an excisional biopsy, primarily because prognosis and treatment are based on tumor thickness. Staging is based on tumor thickness (Breslow's measurement) and histologic level of invasion (Clark level). The current recommendations for excisional removal of confirmed melanomas include 1-cm margins for lesions measuring 1.0 mm or less in thickness and 2-cm margins for lesions from 1.0 mm to 4.0 mm in thickness or Clark's level IV of any thickness. No evidence currently shows that wider margins improve survival in patients with lesions more than 4.0 mm thick. Clinically positive nodes are typically managed by completely removing lymph nodes in the area. Elective lymph node dissection is recommended only for patients who are younger than 60 years with lesions between 1.5 mm and 4.0 mm in thickness. In the Eastern Cooperative Oncology Group Trial, interferon alfa-2b was shown to improve disease-free and overall survival, but in many other trials it has not been shown to be effective at prolonging overall survival. Vaccine therapy is currently being used to stimulate the immune system of melanoma patients with metastatic disease.