What Is Mohs Surgery? How It Works, What to Expect, and When It’s Used

This approach allows the surgeon to confirm that all cancer cells have been removed while preserving as much healthy skin as possible. Because of its precision, Mohs surgery offers very high cure rates and is particularly valuable when treating skin cancers on cosmetically or functionally important areas such as the nose, eyelids, ears, lips, and fingers.

How does Mohs surgery work?

Mohs surgery is performed in stages, usually under local anaesthetic.

First, the visible skin cancer is removed along with a very thin layer of surrounding tissue. This tissue is carefully mapped, processed, and examined under a microscope while the patient waits.

If cancer cells are found at any edge of the removed tissue, the surgeon knows precisely where they remain and removes another thin layer only from that specific area. The process is repeated until no cancer cells are detected.

Because each stage is guided by microscopic examination, Mohs surgery removes the smallest amount of healthy tissue necessary while achieving complete tumour removal.

When is Mohs surgery used?

Mohs surgery is not appropriate for every skin cancer. It is most commonly recommended for basal cell carcinoma (BCC) and selected squamous cell carcinomas (SCC) where preserving healthy tissue is especially important or where there is a higher risk of recurrence.

A specialist may recommend Mohs surgery if the skin cancer:

• Is located on the face, ears, lips, scalp, hands, feet, or genital area
• Has returned after previous treatment
• Has poorly defined borders
• Is larger or more aggressive than usual
• Has developed within previously treated skin

In selected situations, modified forms of Mohs surgery may also be considered for certain early melanomas, such as lentigo maligna, although this is far less common and depends on specialist assessment.

Understanding the most appropriate treatment for your diagnosis is important. If skin cancer has been confirmed, the most suitable skin cancer treatment will depend on the type of cancer, its location, and whether it has spread beyond the skin.

What should you expect on the day?

Mohs surgery is usually performed as a day-case procedure.

After the area has been numbed with local anaesthetic, the surgeon removes the first layer of tissue. While the sample is examined under a microscope, patients usually wait in the clinic. This process may be repeated several times until all cancer cells have been removed.

Because each stage takes time to process, the procedure often lasts several hours. However, much of this time is spent waiting for laboratory analysis rather than undergoing surgery.

Once the margins are clear, the wound is assessed. Depending on its size and location, it may be:

• Closed with stitches
• Reconstructed using a skin flap or skin graft
• Left to heal naturally in selected cases

Your surgical team will explain which option is most appropriate for you.

What are the benefits of Mohs surgery?

One of the biggest advantages of Mohs surgery is that it combines complete margin assessment with maximum preservation of healthy tissue.

Benefits may include:

• Very high cure rates for appropriately selected basal cell carcinomas and selected squamous cell carcinomas
• Removal of the smallest possible amount of healthy skin
• Lower risk of recurrence compared with standard excision in selected high-risk cancers
• Better cosmetic and functional outcomes, particularly on the face and other delicate areas

These advantages make Mohs surgery particularly valuable where both complete cancer removal and tissue preservation are important.

Recovery after Mohs surgery

Recovery varies depending on the size of the wound and how it is repaired.

Most patients experience some swelling, bruising, tenderness, or mild discomfort during the first few days. Pain is usually manageable with simple pain relief.

Most people can return to their usual daily activities within a few days, although recovery depends on the size of the wound and whether reconstruction was required.

Your surgical team will provide detailed wound care instructions, including when dressings should be changed, when stitches may be removed, and when you can return to normal activities.

Although scars continue to mature for several months, most improve significantly with time.

Is Mohs surgery always the best option?

No. Although Mohs surgery is an excellent treatment for many high-risk skin cancers, it is not necessary for every patient.

Some basal cell carcinomas and squamous cell carcinomas can be successfully treated with standard surgical excision, while other cases may be managed with radiotherapy or different treatments depending on the type of skin cancer, its location, and the patient’s overall health.

The most appropriate treatment should always be based on an individual assessment rather than a one-size-fits-all approach. For some patients, seeking advice through a private oncology consultation can provide additional clarity when considering complex treatment decisions or exploring a second opinion.

When might a second opinion be helpful?

It is natural to have questions after a skin cancer diagnosis, particularly if several treatment options have been discussed.

A second opinion may be helpful if:

• You are unsure why Mohs surgery has been recommended
• You have been offered more than one treatment option
• Your skin cancer has returned after previous treatment, or the diagnosis is more complex than expected
• You would like greater confidence before making a treatment decision
• You don’t feel as though you’ve been told about all of the treatment options available to you

A second opinion can help you understand the reasoning behind your treatment plan and ensure you feel fully informed before proceeding.

About Dr James Wilson

Mohs surgery is an important surgical treatment for selected skin cancers, but it is only one part of the wider management of skin cancer.

Dr James Wilson is a consultant clinical oncologist in private practice in London, specialising in the treatment of melanoma and skin cancer. His work includes advanced radiotherapy, immunotherapy, targeted therapies, and systemic cancer care. He helps patients understand their diagnosis, explore treatment options, and make informed decisions through expert consultations and second opinions.