Surgical Excision

How well it works

The table above summarizes the evidence by condition. The detail below adds the key numbers.

For melanoma, surgery is the main treatment. The margin is matched to how deep the melanoma goes. This is one of the most studied questions in skin surgery. In thin melanoma, a 1 cm margin gave the same survival as a 3 cm or wider one.⁶ But the margin can be too narrow. In melanoma 2 mm or thicker, a 1 cm margin led to more cancer returning nearby than a 3 cm margin, and over time more melanoma deaths. So 1 cm is not enough for thicker tumors.⁷⁸ Going wider than needed does not help either. For thicker melanoma a 2 cm margin matched a 4 cm one, and for thinner melanoma 2 cm matched 5 cm.³⁹¹⁰ The trials point to a margin matched to the tumor: wide enough to be safe, not wider.¹¹

For the earliest, surface-only melanoma (melanoma in situ, including the lentigo maligna type on the face), the catch is that it can spread sideways under normal-looking skin. The usual small margin often does not clear it, so a wider or staged removal may be needed.¹²

For basal cell carcinoma, surgery is highly curative. A 4 mm rim of normal skin cleared more than 95% of small, well-defined tumors in a margin study.⁴ In a head-to-head trial of low-risk BCC, surgery cleared 98% of people at 3 years, more than a prescription cream at 84%.¹³ For squamous cell carcinoma, a 4 mm margin cleared most tumors, with a wider margin for higher-risk ones.¹⁴ When cancer is left at the edge, it comes back more often. That is why clear margins matter, and why an involved edge is usually re-removed.¹⁵¹⁶

For high-risk or returning cancers on the face, the edges matter even more, so a margin-controlled removal is used. This includes Mohs surgery, where the surgeon checks the whole edge under the microscope during the procedure. In a 10-year trial of high-risk facial BCC, standard excision had more recurrences than this approach, a difference that was clear for returning tumors.¹⁷ Many recurrences appeared after 5 years, so long follow-up matters.

Scars and recovery

Every excision leaves a scar, and a wider margin means a bigger one. The honest trade-off is that more skin removed can mean more repair work and a longer mark. In a melanoma trial, people treated with the wider margin had more early discomfort and a bit more trouble in the first month, but that settled by 6 months; they did tend to keep a poorer view of their scar.¹⁸ A more recent trial found a wider margin needed more reconstruction and had more wound problems, with no difference in quality of life at a year.¹⁹ The margin is chosen to clear the cancer first; the scar is the cost of doing that well.

Other options patients ask about

People often look for a way to avoid surgery. Here is what the evidence shows.

• A cream instead of surgery is reasonable only for some low-risk, surface-level basal cell carcinomas, and surgery still cures more. In the head-to-head trial, surgery cleared 98% of people vs 84% with the cream.¹³ A cream is not a substitute for surgery for deeper BCC, for squamous cell carcinoma, or for melanoma.
• Black salve and similar corrosive pastes are harmful. They are sold online as a skin cancer cure, but the claims are not backed by evidence. In one series they left cancer behind in the skin and let it hide under a scar, with poor cosmetic results.²⁰
• Cutting or scraping a growth off at home is unsafe. You get no lab diagnosis, the cancer may be left behind, and the wound can get infected. Even edges missed by a trained surgeon raise the chance the cancer returns, and a home attempt has no margin check at all.¹⁵

Why getting the spot checked first matters

The whole value of surgical excision is that it removes the cancer with a measured margin and gives a sample the lab can read. Anything that destroys a growth without a diagnosis, like a corrosive paste or a home removal, throws away both of those. A melanoma or a deeper squamous cell cancer can be left behind, hidden under a scar.²⁰ A spot that is new, changing, bleeding, or different from your others should be examined, and biopsied if needed, then removed properly if it is a cancer. It should not be burned or cut off blind.

When to see a doctor

See a clinician for any spot that is new, changing, bleeding, or not healing, so it can be checked before anything is done to it. After an excision, call your clinician if the wound becomes very painful, oozing, or looks infected, if the stitches open, or if a treated area later forms a new bump or firm spot, since some cancers can return years later.¹⁷

Frequently asked questions

What is a margin? The margin is the rim of normal-looking skin taken around the cancer. A skin cancer can reach a little past its visible edge, so removing a margin gives the best chance of clearing it.⁴ The width is matched to the type and depth of the cancer.²

Is a bigger margin always better? No. For melanoma, trials show a margin matched to the tumor is as safe as a wider one, and a wider margin mainly means a bigger scar and more repair work, not better survival.³¹¹ The goal is a margin wide enough to clear the cancer, not wider.

Will I need stitches, and how big is the scar? Most excisions are closed with stitches and leave a thin line. A wider margin or a tricky spot can mean a larger repair, sometimes a flap or graft. Early discomfort from a wider removal tends to settle within months.¹⁸

What if the lab finds cancer at the edge? That means some cancer may have been left behind, which raises the chance it returns, so the area is usually re-removed.¹⁵¹⁶ This is one reason the lab check is so useful.

Can I treat it with a cream instead? Only for some low-risk, surface-level basal cell carcinomas, and surgery still cures more (98% vs 84% in a head-to-head trial).¹³ A cream is not an option for melanoma or for deeper cancers.

Are at-home removal kits or black salve safe? No. Corrosive pastes are harmful and can leave a cancer hidden under a scar, and home removal gives no diagnosis and no margin check.²⁰ Get the spot examined and treated properly.

Questions to ask your clinician

• Has this spot been examined, and does it need a biopsy before it is removed?
• What margin do you plan to take, and how will the wound be closed?
• Will the sample be checked for clear edges, and how will I hear the result?
• What should I watch for as the wound heals, and when do the stitches come out?
• How will we follow this area over time in case anything returns?

Surgical excision is one of several ways to treat skin cancer. Others, like cryotherapy, creams such as 5-fluorouracil and imiquimod, and photodynamic therapy, fit specific situations. Which one is right depends on the type of cancer, where it is, and your own health. A thorough skin cancer screening is the place to start.

Reviewed by Tyler Long, DO. Last reviewed 2026-06-24.