Can Mohs Surgery Be Used for Melanoma?

How melanoma surgery usually works

The standard operation for melanoma is wide local excision. The surgeon removes the biopsy site and any remaining melanoma together with a measured border of normal-looking skin. For invasive melanoma that border is usually one to two centimeters, roughly three-eighths to three-quarters of an inch, depending on how thick the melanoma is. Melanoma in situ usually starts with a smaller planned margin, though some need more skin removed to clear their edges.

The tissue goes to a pathology laboratory, where sections are examined to describe the tumor and check whether it reaches the edges of the specimen. Results usually take several days. Wide excision is the guideline-recommended standard for invasive melanoma and works well for many patients. Standard pathology samples the edges rather than examining the complete outer and deep margins the way Mohs does. If melanoma is found at an edge, another operation may be needed.

How Mohs surgery for melanoma is different

During Mohs, the surgeon removes the tissue in carefully mapped stages. The outer and deep edges of each stage are prepared and examined under the microscope while you wait. If melanoma is found at an edge, the surgeon removes another thin layer from exactly that spot and checks again. Repair is planned once the examined margins are clear.

Melanoma Mohs needs specialized laboratory methods. Special stains, MART-1 and SOX10, highlight melanocytes, the pigment cells melanoma arises from. The stains highlight normal pigment cells too, so the surgeon reads the pattern, the number, and the arrangement of the stained cells to judge whether melanoma is present. Our laboratory runs these stains in-house during your surgery, which is what makes same-day margin assessment possible. Appropriate cases have removal and repair in the same visit; some need additional testing or a different repair plan.

Checking mapped margins also helps preserve healthy skin while the melanoma is removed. That matters most near the eyes, nose, lips, and ears, where extra tissue removal affects function and repair. The central tumor tissue is examined separately to confirm depth and the other features that guide staging. Occasionally this shows a higher stage than the original biopsy suggested and changes the plan. In one published Mohs series, 5.5 percent of melanomas were upstaged this way, and almost all were identified before repair.

Recurrence: what the numbers show

Many studies of melanoma Mohs focus on local recurrence, meaning melanoma returning at the treated spot. A 2022 systematic review pooled 71 published studies covering 16,575 patients. The pooled local recurrence estimates were about 7 percent after wide local excision, 3 percent after staged excision, and less than 1 percent after Mohs. Staged excision also uses mapped margins, usually with laboratory processing that takes longer. The studies included different tumors and follow-up periods, so these figures are a pattern across the literature, not a direct comparison of otherwise identical patients.

Several individual Mohs series report low local recurrence too, although they have no wide-excision group to compare against. In a multicenter study of 785 invasive melanomas of the head and neck treated with Mohs and MART-1 staining, four local recurrences were reported, about half of one percent, over a twelve-year study period. Another series reported seven local recurrences among 1,419 primary melanomas, again about half of one percent. In a separate single-center study of melanoma in situ, estimated five-year recurrence was 1.1 percent after Mohs and 4.1 percent after wide excision, a difference that was not statistically conclusive.

Survival: the newest evidence

Keeping melanoma from returning at the treated spot is important, but it is not the same as preventing spread or death. Survival comparisons between Mohs and wide excision come from observational studies, which can show an association but cannot prove that the operation caused a difference.

A 2026 study used the U.S. SEER cancer registry to compare melanoma-specific survival after Mohs and after wide excision in more than 90,000 patients with invasive melanoma treated between 2000 and 2020. The reported five-year melanoma-specific survival was 93 percent after Mohs and 88 percent after wide excision. At ten years it was 88 percent and 83 percent. These figures count deaths attributed to melanoma, not deaths from all causes, and they were not adjusted for the differences between the two groups. The authors also reported that an association favoring Mohs remained after statistical adjustment, but adjustment cannot make the groups fully comparable.

The same estimates, shown with 100 squares

The display below shows the same survival estimates in another form. Each square is one percentage point, not an individual patient. The gap is five percentage points at both time points. That does not tell us how many lives either operation saved.

What this study can and cannot tell you

This was a registry study, not a randomized trial, and the two groups were not the same to begin with. Patients treated with Mohs generally had thinner, earlier-stage tumors, more often on the head and neck, and more often of the lentigo maligna melanoma subtype. Statistical adjustment tries to account for the differences that were measured, but important differences can remain, including overall health and the other care each patient received. The authors describe their finding as a potential advantage that deserves confirmation in prospective studies, and we agree.

Other registry studies give useful context, though several drew on overlapping years of the same national database and should not be counted as fully independent confirmations. A 2019 study of stage I invasive melanoma and a 2020 study of head and neck melanoma both reported better overall survival among patients treated with Mohs. Overall survival includes deaths from all causes, so general health can influence those results. A 2021 study of melanoma on the trunk and limbs found no statistically significant survival difference between the two operations.

Taken together, these studies support considering Mohs for appropriately selected melanomas. They do not prove that Mohs is better than wide excision for survival, and they do not prove the two are equivalent. The choice depends on the melanoma's features, its location, what staging it needs, and the expertise available.

Who may be a candidate

Mohs may be considered when a melanoma's borders are hard to define or when preserving nearby healthy skin matters. These are reasons for an assessment, not automatic eligibility:

• Selected melanoma in situ, including lentigo maligna, especially on the face, scalp, ears, and neck, where the cancer often extends beyond its visible edge
• Selected thin invasive melanomas in areas where preserving tissue helps protect function or simplify repair, after reviewing tumor depth and any need for lymph node evaluation
• Some melanomas with tumor remaining at a previous surgical margin, or a local recurrence, after the diagnosis and stage have been reassessed
• Melanomas with poorly defined borders

When wide excision is the right choice

Wide local excision remains the standard operation for invasive melanoma and is often the most appropriate approach, including for many melanomas on the trunk and limbs. Tumor thickness and other pathology findings determine whether a sentinel lymph node biopsy should be discussed. If melanoma has already been found in a lymph node, that calls for a separate staging and treatment plan. We recommend, or coordinate, whatever care your melanoma needs.

The decision weighs tumor thickness, ulceration and other pathology findings, location, lymph node evaluation, your health, and your preferences. Your surgeon will explain the recommendation and bring in another specialist when that is the right thing to do.