A retrospective observational study of primary cutaneous malignant melanoma patients treated with excision only compared with excision biopsy followed by wider local excision

For primary cutaneous malignant melanoma the guidelines recommend an excision biopsy of the suspected lesion followed by wider local excision; the diagnosis can then be confirmed and excision margins planned.

To compare retrospectively the clinicopathological features, surgical margins and survival of patients from the Scottish Melanoma Group database whose tumour was removed by excision only (one-stage) or excision biopsy followed by wider local excision (two-stage) surgery.

The Scottish Melanoma Group database records the clinicopathological features, surgical treatment and follow-up information of all patients with malignant melanoma in Scotland. From this 1595 patients were identified over a 19-year interval from 1979 to 1997 with follow-up until the end of December 1999. Overall survival, disease-free survival and recurrence-free interval were examined with univariate and multivariate statistical methods.

The patients in the one-stage excision group (n = 547) were statistically significantly older (P < 0.001), had thicker melanomas (P < 0.001), a higher proportion of lentigo maligna melanomas (P < 0.001), head and neck (P < 0.001), and ulcerated lesions (P < 0.003) compared with the two-stage group (n = 1048). The margins of excision were significantly narrower in the one-stage compared with the two-stage group (P < 1 x 10(-5)). Fifty-two percent of all one-stage excisions were performed with a margin < 1 cm compared with 20% of the two-stage group. The excision margin was more positively correlated with the Breslow thickness for the two-stage over the one-stage group (Spearman rho = 0.38, P < 0.001; and 0.27, P < 0.001, respectively). Overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RF) were all statistically significantly better in the two-stage compared with the one-stage excision group, P < 1 x 10(-5), P < 1 x 10(-5) and P = 0.001, respectively (log rank test). After adjusting for the prognostic factors of age, sex, tumour thickness, site, histology and ulceration, OS, DFS and RF were still significantly better in the two-stage compared with the one-stage group [hazard ratio (HR) 0.75, 95% confidence interval (CI) 0.61-0.92, P = 0.006; HR 0.75, CI 0.62-0.90, P = 0.002; and HR 0.78, CI 0.62-0.99, P = 0.04, respectively].

This study showed that one-stage excisions were more common in patients with poorer prognostic features and that excision with margins narrower than those suggested by current guidelines was more likely. Patient survival was statistically significantly better with the two-stage procedure, although the reasons for this were unclear.