Skin cancer excision

A skin cancer excision removes the cancer together with a measured border of apparently normal skin around it. That border is the surgical margin, and its purpose is to reduce the chance that cancer cells remain at the edges of the wound. It is the reason the wound is almost always larger than the spot you can see — often considerably so. How wide the margin needs to be is not a fixed number: it depends on the type of cancer, its depth and microscopic features, its size and location, whether it is a first or a recurrent cancer, and the state of the surrounding skin.

Anaesthetic: Local, or sedation or general for larger cases
Hospital stay: Usually a day case
Time off work: Varies with site and closure
Final result: Scars mature over 12–18 months

A general guide only — your own timeline is confirmed at consultation.

What it involves

Most excisions are performed under local anaesthetic, so you stay awake while the area is numbed — you may feel pressure or movement, but should not feel sharp pain. Larger or more complex cases may need sedation or a general anaesthetic. The operation runs in a set sequence:

The lesion and the planned surgical margin are marked
The skin is cleaned and local anaesthetic injected
The lesion and its margin are removed
The specimen is marked for orientation and sent to the pathology laboratory
Bleeding is controlled
The wound is closed or reconstructed
A dressing is applied

Who it may suit

For patients with a confirmed or suspected skin cancer. Dr Chen's MMed research was in skin oncology and reconstruction after skin-cancer treatment, and that work informs how these cases are planned — the removal and the repair are designed together rather than one after the other. How much skin has to come out is decided case by case, according to:

The type of skin cancer
The thickness or depth of the tumour
Its microscopic features
Its size and location
Whether it is a first or a recurrent cancer
The health of the surrounding skin, and any previous treatment

Recovery

Most excisions are day procedures. Recovery depends far more on where the cancer was and how the wound was closed than on the excision itself. Follow the wound-care instructions you are given rather than general advice, and do not use antiseptics, creams or home remedies unless the team has recommended them. A small amount of spotting on the dressing can be normal; persistent or heavy bleeding needs attention — sit or lie down and apply firm, continuous pressure over the dressing for fifteen to twenty minutes without lifting it to check, and if it continues, contact us or seek urgent care. Scars are red, firm or raised at first and take twelve to eighteen months, sometimes longer, to mature:

Keep the dressing clean and dry, and leave the original dressing in place for the period advised
Avoid stretching, bending, lifting, exercise or pressure on the wound
Sleep with the operated area elevated where practical
Attend for dressing changes, wound review and suture removal on the dates advised
Protect the healing scar from sunlight
Avoid smoking and nicotine — both reduce blood flow and raise the risk of poor healing, infection, and graft or flap failure

This page is a general guide. Every procedure is planned individually — the details, risks and recovery relevant to you are discussed at consultation.

Common questions

Why is the wound so much bigger than the spot?

Because of the margin. The visible lesion is only the part you can see; the excision takes it together with a measured border of normal-looking skin around and beneath it, to reduce the chance that cancer cells are left at the edge. On top of that, a round defect usually has to be closed as an ellipse so the skin lies flat, which lengthens the scar further. The expected size and position of the wound is explained before surgery, so it should not come as a surprise on the day.

When will I get the result, and what if the margins are not clear?

The tissue goes to a pathology laboratory, which reports the type of cancer, its depth and microscopic features, and whether it has been completely removed. Results often take a week or more, and the timing varies between laboratories — a delay does not in itself mean anything is wrong. A 'clear' margin means no cancer cells are seen at the cut edge. If cells are present at or close to an edge, further treatment may be advised: a wider excision, Mohs surgery, radiotherapy, or in selected cases a non-surgical treatment. Needing further surgery does not mean the cancer has spread — usually it simply means the original site needs to be completely treated.

How will the wound be closed?

That depends on the size, depth and site of the defect. Small wounds are often closed directly, with the edges brought together. Some are left to heal gradually from the base, which needs regular dressings. Larger wounds may need a skin graft, taken from elsewhere on the body, or a local flap, where neighbouring skin and tissue are moved in while keeping their own blood supply. The reconstruction is planned at the same time as the excision, not afterwards.

What is Mohs surgery, and how is it different from a standard excision?

The difference is in how the margin is examined. In a standard excision the specimen is sliced at intervals, rather like a loaf of bread, and the pathologist examines those slices — which represent only a proportion of the true edge, so a positive area lying between two slices can be missed. In Mohs, the layer is removed as a mapped, oriented specimen: it is divided, inked and drawn onto a map, then sectioned so that the entire peripheral and deep margin is examined rather than sampled. Anything still positive can be located on the map, and only that area is re-excised. That is what allows the cancer to be cleared while sparing the greatest possible amount of healthy tissue, which matters most on the face.

Do you offer Mohs surgery?

Not Mohs itself. Mohs is performed in specialised units, and where it is clearly the right approach for a particular cancer we will say so and refer you. Most skin cancers do not need it. The standard operation is an excision with an appropriate margin, with reconstruction where it is needed. In selected cases — particularly in cosmetically sensitive areas — we use a staged approach instead: the lesion is excised, the wound is dressed, and we wait for the histology before reconstructing. The reconstruction is planned and performed only once the margins are confirmed clear. For selected skin cancers, a carefully planned staged excision with thorough microscopic assessment of the margins can achieve rates of complete clearance comparable to Mohs surgery, and it is far more widely available in South Africa. The trade-off is real — more than one procedure, and a longer overall process. What you gain is that nothing is reconstructed over a cancer that has not been fully cleared, and a flap or graft does not have to be taken down and redone if the margins come back positive.

What happens if it turns out to be a melanoma?

A wider local excision is usually recommended, and how much additional skin is removed depends mainly on the melanoma's measured thickness and stage. Depending on the findings, you may also be offered examination or ultrasound of the nearby lymph nodes, a sentinel lymph-node biopsy, scans, genetic testing of the tumour, or systemic treatment, with specialist oncology follow-up. None of these is needed for every melanoma — the recommendations that apply to you are discussed with the team treating you.

Am I likely to get another one?

Having had one skin cancer does increase the risk of developing another, which is why follow-up and self-examination matter as much as the operation. Check your whole skin surface, including the scalp, ears, back, palms, soles, between the toes and under the nails, and ask someone to look at the places you cannot see. Reduce ultraviolet exposure with shade, clothing, a broad-brimmed hat and a high-factor broad-spectrum sunscreen reapplied regularly — but do not use sunscreen as a reason to stay out longer in strong sun. Do not wait for a scheduled appointment if you notice a new or changing lesion, a lump near the treated area, or a change in the scar.