Commentary on “Recurrence Rate for Melanoma Excised by Mohs Micrographic Surgery Without Immunostaining”

Abstract

M ohs micrographic surgery is becoming an increasingly utilized therapy for noninvasive and early-stage melanoma of the head and neck. 1 Data have emerged supporting this practice, highlighting lower rates of recurrence with Mohs and complete circumferential peripheral and deep margin assessment over conventional wide local excision. [2][3][4][5] Specific practice patterns vary, as do outcomes among treatment facilities with differing volumes. 6 With these discrepancies come a calling for standardization of best practices. In this edition of Dermatologic Surgery, Vieira and colleagues 7 publish a retrospective cohort study of 224 cases of cutaneous melanoma treated at a tertiary academic center with Mohs micrographic surgery, without immunostaining, by a single surgeon.The technique utilized in the study was outlined thoroughly in the article. To begin, a standard 5-mm margin was taken for all melanomas, with narrower margins considered on a case-by-case basis. The current guidelines of the National Comprehensive Cancer Network 8 recommend a wide local excision to the level of fascia with 1-cm margins for T1a melanoma, and a margin of 0.5 to 1 cm for melanoma in situ. The guidelines caution that more narrow margins may increase the risk for margin positivity and/or local recurrence. In fact, the guidelines stress that "the gold standard for histologic assessment of excised melanoma is use of permanent sections" and state that Mohs surgery "may be considered selectively for minimally invasive (T1a) melanomas in anatomically constrained areas". Despite data showing equivalent or superior outcomes, there remains resistance to the acceptance of Mohs surgery for invasive melanoma.The second point of discussion is that immunostains were not utilized in this study. The majority of Mohs surgeons performing Mohs surgery on melanoma in situ and invasive melanoma today do utilize immunohistochemistry, 9 but this, too, is a source of dissension. A recent review of technical variations for Mohs micrographic surgery for melanoma reported that 45.8% of surgeons utilized MART-1, 20.8% utilized other immunohistochemistry (IHC) either in place of or in addition to MART-1, such as HMB-45, MEL-5, and S100, and 33.3% did not use IHC at all.