The effects of surgical treatment on survival and local recurrence of cutaneous malignant melanoma.

All patients with a diagnosis of cutaneous malignant melanoma (CMM) in Western Australia from 1980 to 1981 were observed for up to 6 years to determine vital status and to detect the development of local recurrences of the primary lesion. Approximately 35% of all patients had their tumors excised with surgical margins of less than 1 cm. When compared with patients whose tumors were excised with margins of at least 2 cm, the fatality rate in those with narrow margins was slightly less (rate ratio, 0.60; 95% confidence interval [CI], 0.20% to 1.80% for margins of 5 to 9 mm; rate ratio, 0.69; 95% CI, 0.26% to 1.87% for margins of 1 to 4 mm); however, this difference could have been caused by chance alone. The risk of local recurrence within 5 years after diagnosis was 2% (95% CI, 1% to 4%). The risk was strongly related to age and tumor thickness, but did not appear to be influenced by the width of excision (greater than 1 cm versus less than 1 cm: rate ratio, 1.03; 95% CI, 0.25% to 4.34%). The apparent lack of effect could be caused by to chance alone because the number of local recurrences was small.