Narrow versus wide margins in malignant melanoma.

Although wide surgical excision is the accepted treatment for thin malignant melanomas, there is reason to believe that narrower margins may be adequate. A randomized prospective study to assess the efficacy of narrow excision (excision with 1-cm margins) for primary melanomas no thicker than 2 mm was conducted at the National Institute of Health in Milan, Italy, and five other countries. Narrow excision was performed in 305 patients and wide excision (margins of 3 cm or more) in 307 patients. The major prognostic criteria were well balanced in the two groups. The mean thickness of the melanomas was 0.99 mm in the narrow-excision group and 1.02 mm in the wide-excision group. The subsequent development of metastatic disease involving regional nodes and distant organs was not different in the two groups (4.6% and 2.3%, respectively, in the narrow-excision group as compared with 6.5% and 2.6% in the wide-excision group). Disease-free survival rates and overall survival rates (mean follow-up period was 55 months) were also similar in the two groups. Only three patients had a local recurrence as a first relapse. All had undergone narrow excision, and each had a primary melanoma with a thickness of 1 mm or greater.