Optimizing Outcomes for Cutaneous Head and Neck Melanoma

Abstract

In this issue, Moyer and colleagues 1 report long-term follow-up of a large cohort of patients with head and neck melanoma treated with a "square" staged excision technique using permanent sections for comprehensive margin assessment. The median follow-up of 9.3 years demonstrated excellent long-term disease control of 834 lesions with projected local recurrence rate of 2.2% at 10 years. The mean margin required for histologic clearance of tumor was 9.3 mm for melanoma in situ and 13.7 mm for invasive melanoma. The authors demonstrated that lesion size, presence of invasion, and prior incomplete excision were associated with larger surgical margins required for histologic clearance.Melanoma of the lentigo maligna subtype accounted for nearly 75% of the head and neck melanomas in this series. This is a critical point because melanomas developing in an area of chronic photodamage in the head and neck region present many challenges. Lentigo maligna has had a long, confusing history. It was initially called Hutchinson's melanotic freckle in the 1800s and felt to be an infectious process. Lentigo maligna is still misconstrued by some as a premalignant lesion. It is now well-recognized as a subtype of melanoma in situ. Once invasion is present, melanoma staging 2 and prognosis are directly related to tumor thickness, similar to other melanomas, with potential for metastasis and death, and should be treated according to current melanoma standards. 3 Following these guidelines, patients in this study underwent sentinel lymph node biopsy if indicated.It is now well-established, in the dermatologic literature, that standard surgical margins for excision of melanomas on the trunk and extremities are frequently inadequate when applied to melanomas of the head and neck region. This study further supports this finding, because only 25% of melanoma in situ lesions were cleared with a 0.5-cm margin, and only 25% of invasive melanomas were cleared with a 1-cm margin. The National Comprehensive Cancer Network clinical practice guidelines clearly state that for melanomas of the "lentigo maligna type, greater than 0.5 cm may be necessary to achieve histologically negative margins," and that "exhaustive histologic assessment of margins should be considered." 3 The surgical treatment of melanoma of the lentigo maligna type has therefore evolved from standard wide excision to staged techniques that allow enhanced margin evaluation and reduce local recurrence. However, there remains debate in the field of dermatologic surgery over the ideal method of margin examination for these challenging melanomas, ranging from per-

Correlation of Handheld Reflectance Confocal Microscopy With Radial Video Mosaicing for Margin Mapping of Lentigo Maligna and Lentigo Maligna Melanoma

“…Although dermoscopy and Wood lamp examination have been used to guide LM excisions, in our study in approximately 40% of the quadrants, HRCM identified LM and/or LMM extending beyond the dermoscopic and Wood lamp margins. These results highlight that HRCM improves LM and LMM margin evaluation and confirm the need for increased surgical margins to achieve clear margins . We used an imaging approach that parallels the design of staged excision with radial histopathologic sectioning by imaging with HRCM radially from the center to the periphery.…”

“…These results highlight that HRCM improves LM and LMM margin evaluation 12,14,15 and confirm the need for increased surgical margins to achieve clear margins. 4,[24][25][26] We used an imaging approach that parallels the design of staged excision with radial histopathologic sectioning by imaging with HRCM radially from the center to the periphery. Our results suggest that HRCM-RV correlates with surgical defects after staged excision of LM and LMM, although the mean HRCM-RV estimates were smaller than the actual defect.…”