Melanoma resection margin recommendations, unconventionally based on available facts.

: Precedent from early in the twentieth century led to the traditionally wide resection margins for primary melanoma, but at that time there was little relevant empirical evidence that substantiated the efficacy of the practice. Later, neither numerous retrospective analyses nor several prospective, randomized trials were able to demonstrate an adverse effect on outcome from melanoma with narrowing of margins to 1 cm. A slightly increased rate of local recurrence was observed in some nonrandomized analyses when margins were less than 1 cm, an effect that may be accentuated with thicker primary tumors. The factual record therefore does not support the use of resection margins greater than 1 cm for invasive melanoma of any thickness.