Long-term study results show that a wider surgical margin for cutaneous melanomas greater than 2-mm thick improved melanoma-specific survival vs a 1-cm margin.
Long-term follow-up from a large randomized study has shown that a wider surgical margin for cutaneous melanomas greater than 2 mm in thickness improved melanoma-specific survival when compared with a surgical margin of 1 cm.
The 5-year results of this trial were published previously by Andrew J. Hayes, MD, of the Royal Marsden National Health Service Foundation Trust in the United Kingdom, and colleagues, and showed that a narrow surgical margin resulted in increased frequency of locoregional relapse, but had no significant effect on overall survival. The long-term results, published in Lancet Oncology, confirmed that the size of the surgical margin did not have a statistically significant effect on overall survival.
“Our study has re-emphasised that the choice of surgical margins taken around a cutaneous melanoma is important and, to our knowledge, for the first time provides evidence to suggest that a narrower excision margin used for thick primary tumours affects melanoma-specific survival,” wrote Hayes and colleagues. “This finding might be pertinent for specific melanomas for which narrow (1 cm) margins are presently advised-ie, melanomas between 1 mm and 2 mm in thickness with other adverse prognostic features (ulceration or high mitotic rate, or both).”
This study enrolled patients with one primary cutaneous melanoma greater than 2 mm in thickness from 59 hospitals between 1992 and 2001. The patients were randomly assigned to surgery with either 1-cm excision margin (narrow; n = 453) or 3-cm excision margin (wide; n = 447).
This long-term analysis was conducted with 8.8 years of follow-up. At this time, 494 patients had died; 359 from melanoma. Melanoma-specific deaths occurred in 194 patients in the 1-cm group compared with 165 in the 3-cm group (unadjusted hazard ratio [HR], 1.24 [95% confidence interval (CI), 1.01–1.53]; P = .041). The estimated absolute difference between the two groups in melanoma-specific survival at 10 years was 5.95% (95% CI, -0.54–12.44).
Overall, a greater number of patients assigned to the 1-cm group (253) died compared with the 3-cm group (241); however, this numerical difference was not statistically significant (unadjusted HR, 1.14 [95% CI, 0.96–1.36]; P = .14).
“Current international guidelines advise a 2-cm excision for melanomas greater than 2 mm in thickness and findings from the other major randomised study for thick melanomas suggested that a 4-cm excision was not better than a 2-cm excision in terms of melanoma-specific survival,” wrote the researchers. “Hence, although the findings from our study suggest that a 1-cm margin seems inadequate for excision of melanomas thicker than 2 mm, margins greater than 2 cm need not necessarily be taken.”