The vertical dimension in the surgical treatment of cutaneous malignant melanoma - how deep is deep?

The surgical treatment of primary cutaneous malignant melanoma has been an issue of debate throughout the past decades. It is generally accepted that the excised tumor-free surgical margins around the lesion should be proport ional to the lesion thickness. However, the issue of adequate thickness of tumor-free margins to be resected in the depth of the lesion has not been a ddressed as vet. In order to assess the influence of thickness of the tumor -free margins resected under malignant melanoma on patients outcome, we hav e reviewed 48 patients treated for primary cutaneous malignant melanoma in the Rabin Medical Center in the years 1987-1988. Biopsy specimens and clini cal charts were evaluated. the tumor-free margin in depth of the excision w as measured and compared with clinical outcome. The study population compri sed 21 men and 27 women with an average age of 60.2+/-15.2 years. Most of t he primary melanomas were of intermediate thickness with a mean Breslow thi ckness of 1.6 mm. During a median follow up time of 112.8 months, ten (21%) patients developed relapse of their malignancy and 13 patients (27.08%) di ed. In univariate analysis. the thickness of the tumor-free margin excised under the melanoma was one of seven clinical and pathological variables tha t showed significant predictive value for patient survival. The 10-year sur vival rate in patients with tumor-free margins thinner than 3 mm was 50%, c ompared with 82% in patients with thicker tumor-free margins (P=0.01). In m ultivariate analysis, these margins remained an independent significant pro gnostic factor, as were four other variables. Evidence indicating a tendenc y for local and distant melanoma recurrence in thin excisions with Small ma rgin/tumor thickness ratio was detected. The recurrence rate in the group w ith margin/tumor thickness ratio smaller than I was nearly five times highe r than the rate in patients with higher ratios (6% vs 14%, P=0.003). In uni variate and multivariate analysis of 10 years survival, this ratio also pro ved to be an independent prognostic factor. In this study we have shown tha t the tumor-free margins resected under the lesion play an important role i n the comprehensive surgical treatment of primary cutaneous melanoma and in determining the clinical outcome of the patients.