Skin lesion suspicious of melanoma: time to one-step removal

We read with interest the recent study by Brian and Jameson¹ on compliance with clearance margins recommended by the Clinical Practice Guidelines for the Management of Melanoma in Australia and New Zealand. These guidelines recommend a 2 mm horizontal margin for cases of suspected melanoma treated with excision biopsy.² The recommendation of similar margins in many countries is beginning to stir debate on this topic.^3,4

The 2 mm recommendation is a low-grade recommendation (C) supported by an even lower level of evidence (IV).² The main reason for such a small margin is not to interfere with lymphatic drainage as sentinel lymph node (SLN) biopsy may be indicated. However, SLN biopsy does not improve melanoma-specific survival,⁵ and neither does complete lymph node dissection following a positive biopsy, highlighting the need for reassessment of how primary melanomas should be managed.

One option that merits evaluation is one-step surgery for suspected in situ or thin melanomas as these account for a large proportion of incident cases of primary tumours.⁶ Although no tools are yet available for confirming a diagnosis of melanoma before excision, dermoscopy is very useful for distinguishing between nevus and melanoma in situ.⁷ The distinction between in situ and invasive melanoma is somewhat less clear.⁸

We propose performing one-step excision with a 10-mm horizontal clearance margin (Fig. 1) in patients with lesions that are strongly suspected to be melanoma located in suitable anatomic sites. This approach would avoid the need for re-excision in the case of thin melanomas (≤ 1 mm) or in situ melanomas. Its limitation is that the margin taken in the case of an in situ melanoma would be 5 mm larger than that recommended by clinical practice guidelines, but we believe that the aesthetic outcome is acceptable.

Fig. 1.  (a) Superficial spreading melanoma that following one-step excision (c), (d) was found to have a thickness of 0.65 mm. Dermoscopy (b) showed a multicomponent pattern characterised by asymmetry in two axes, atypical globules, an atypical network, and four colours.

This one-step approach would reduce costs and could even have a favourable psychological impact, as some patients scheduled for re-excision believe that their prognosis has worsened.⁹

The authors declare no conflicts of interest.

This research did not receive any specific funding.