Surgical Margins in Melanoma

  • The standards set for wide excision of melanoma:
    • Are well-studied and are the result of:
      • Five randomized, prospective trials
  • Two trials:
    • The French Cooperative Group Trial and the Swedish Melanoma Trial Group:
      • Analyzed melanomas 2 mm in depth
      • Comparing 2-cm and 5-cm margins
      • The findings of these studies demonstrated:
        • No increased risk of local or distant recurrence associated with the smaller margin
  • The World Health Organization (WHO) Melanoma Trial number 10:
    • Also analyzed patients with melanomas 2 mm in thickness:
      • But compared 1-cm and 3-cm margins
    • It also demonstrated no difference in overall survival:
      • Although among the patients with a melanoma of 1- to 2-mm thickness:
        • The rate of local recurrence was slightly higher when a 1-cm margin was used:
          • The difference was not statistically significant, however:
            • And the recommendation from this trial was that a 1-cm margin was safe for lesions 2 mm Breslow thickness:
              • Although the rate of local recurrence in the 1- to 2-mm subgroup may be higher with this margin
  • The Intergroup Melanoma Trial:
    • Analyzed all patients with a melanoma of intermediate thickness (1 to 4 mm)
    • The authors compared 2-cm and 4-cm margins and, despite the inclusion of patients with melanomas 2 mm thick:
      • No difference was seen in overall survival or local recurrence
    • This trial demonstrated that a 2-cm margin of excision was safe for patients with a melanoma of up to 4 mm thick:
      • But did not address patients who had a lesion greater than 4 mm thick
  • The British Cooperative Group Trial:
    • Analyzed patients with lesions greater than 2 mm in thickness and randomly assigned them to 1-cm margins or 3-cm margins
    • This trial demonstrated a greater risk of recurrence among patients who had a 1-cm margin of excision:
      • However, importantly, this trial did not include SLN biopsy, and the greatest incidence of recurrence was regional:
        • When accounting for regional recurrence, the differences between groups were no longer statistically significant
      • Given this limitation, the application of these results to the standards in regions where SLN is routinely applied becomes somewhat ambiguous
      • Finally, the overall survival in both arms was not statistically different
  • Margins are measured grossly, not microscopically:
    • Therefore pathologic analysis after resection does not require repeat resection (except in the setting of positive margins) to ensure the appropriate distance
    • There is no role for compromise of these standards, i.e., biopsy margins cannot be added to planned surgical margins to obtain a total excision margin (i.e., 5 mm plus 5 mm):
      • Therefore, wide excision is planned around the biopsy site or the known primary lesion with the appropriate margin at the time of definitive wide excision:
        • In areas of anatomic or functional constraint, such as the hand or the face:
          • Margins may be compromised from the set standards:
          • In settings where margins must be compromised:
            • Local recurrence does not appear to have an impact on overall survival
  • Sentinel lymph node biopsy:
    • Should be discussed and offered for patients with melanoma greater than or equal to 0.8 mm in thickness
    • Melanomas less than 0.8 mm thick with the presence of high-risk features such as:
      • The presence of ulceration
  • Ultrasound surveillance of the regional lymph node basin(s):
    • Would be indicated only in the instance of a primary tumor that failed to localize on preoperative lymphoscintigraphy
  • Reference
    • Balch CM, Houghton AN, Sober AJ, et al, eds. Cutaneous Melanoma. 5th ed. St. Louis, MO: Quality Medical Publishing; 2009.
    • National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology. Melanoma. Available at
    • Morton DL, Cochran AJ, Thompson JF, et al. Sentinel node biopsy for early stage melanoma: accuracy and morbidity in MSLT-I, an international multicenter trial. Ann Surg. 2005;242:302-311.

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