Excision simply means “to cut out.” Surgical excision can be used to treat melanoma and non-melanoma skin cancer. Excision is also called “wide excision.” This is because the tumor is cut out together with some of the healthy skin around it. The healthy skin is called a margin. The reason for taking a margin is to remove any cancer cells that have spread into the surrounding tissue.
The complexity of the excision depends on the tumor type, size, and location. The simplest and most common way to excise a tumor is a technique called elliptical excision. Excision and repair are more complicated for tumors on the scalp, foot, or other tricky places.
After a tumor is excised, a pathologist will study the tissue that was removed. This is done to be certain that all the cancer cells are gone.
How is elliptical excision performed?
Elliptical excision is the most common way to excise a tumor.1 Your dermatologist will draw the margin around the tumor. For a low-risk non-melanoma skin cancer, the margin may be as narrow as 4 millimeters (mm). For a thick melanoma, the margin may be as wide as 2 centimeters (cm).2,3 If you had an excisional biopsy, your doctor will mark the margins from the biopsy scar.1
Your dermatologist will cut an elliptical (football) shape around the margin. An elliptical cut removes more skin than a circle would, but results in a better looking scar.4 Your doctor will close the incision with stitches. The scar will look like a thin, flat line.4
How are tumors excised from complex areas?
Excision of tumors on some parts of the body can be tricky. Tricky areas include the face, ear, scalp, sole of the foot, fingers, and toes. If tumors are excised from these areas, it may not be possible to stretch the skin over the site to close it. Special repairs may be needed.1 Examples of repair procedures are skin grafts or flaps. Margins in these areas may be smaller.3
How is excision different for treatment and biopsy?
The main difference between excision for treatment and for biopsy is the size of the margin. The margins for biopsy are 1 to 3 millimeters (mm).3 The margins for confirmed skin cancers range from 4 mm to 2 cm.2,3
What types of skin cancer are excised?
Excision is used to treat melanoma and non-melanoma skin tumors.
Excision is the main treatment for melanoma.3 The margins are based on how thick (deep) the tumor is.3 Large studies have shown that margins wider than 3 cm do not improve survival.3 If the border of the tumor is unclear, it can be difficult to determine the margins. Lentigo maligna melanoma and melanoma in situ (melanoma in the outer layer of skin) are challenging in this way.3
Recommended Margins for Melanoma
Low-risk non-melanoma skin cancer
Excision is one treatment option for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Low-risk BCC is excised with a 4-mm margin.2 Low-risk SCC is excised with a 4 to 6 mm margin.5 Depending on location and size, the incision may be left to close on its own. Alternatively, your doctor may close it with stitches or repair it with a skin graft. Your doctor will send the tumor to a pathologist. If the margins are clear, then the cancer has been cured. This surgery cures about 98% of low-risk BCC and 92% of low-risk SCC.2
High-risk non-melanoma skin cancer
Excision is also a treatment option for high-risk BCC or SCC. High-risk BCC is more likely to return (recur). High-risk SCC is more likely to recur or spread. Therefore, your doctor will use wider margins to remove these cancers.2 Additionally, a pathologist may check the excised tumor while you are still in surgery. Your surgeon will not close the incision until the margins are clear.2,5
Merkel cell carcinoma
Wide excision is used to remove Merkel cell carcinoma tumors.6 This surgery will cure early Merkel cell carcinoma that has not spread beyond the skin.
Excision can be used when there are only a few Kaposi sarcoma lesions to remove.7 Tumors may grow back (recur) in the same spot.7
What should I expect before, during, and after excision?
The best type of doctor and setting for excision will depend on tumor size, location, and type. Thin melanomas and low-risk non-melanoma skin cancers can be excised in a doctor’s office. A numbing medicine (local anesthesia) will be injected at the tumor. After the procedure, you will be given instructions on how to care for the incision.
Excision of thicker melanomas may be done at the same time as sentinel lymph node biopsy. This procedure is usually done at the hospital under general anesthesia. Often it is an outpatient (same day) surgery, although sometimes patients stay overnight.
What are the risks of this procedure?
You will have a scar after excision. Before your surgery, talk to your doctor about how the scar may look.
Possible complications of excision include:8
- Pain and discomfort
- Incision re-opening
- Nerve damage
- Reaction to the numbing medication (anesthetic) or sutures
Margin descriptions: what do they mean?
Pathologists, doctors, and patients may use different terms to describe margins. After a tumor is surgically removed, a pathologist will study it. The pathologist checks the edges of the sample for cancer cells.Below are some common terms with their definition.3,9,10
- Negative margin: No cancer cells found at the edge of the sample
- Clean margin: No cancer cells found at the edge of the sample
- Clear margin: The tissue around the tumor is healthy and cancer free
- Close margin: Vague term which means cancer cells are 1 mm to 5 mm away from the edge of the sample
- Positive margin: Cancer cells found at the edge of the sample, suggesting that the cancer has not been entirely removed
- Involved margin: Cancer cells found at the edge of the sample, suggesting that the cancer has not been entirely removed
Sources: National Cancer Institute. Dictionary of Cancer Terms; NCCN Clinical Practice Guidelines in Oncology. Melanoma. Version 1.2017; Ranjan R, et al. Indian J Dermatol. 2014;59:567-570.
What happens if the margins are positive?
The pathologist will check whether the cancer cells extended to the edge of the sample. If they do, the margins are “positive” or “involved.” You will need additional treatment to remove all the cancer cells. Treatment may include:1-3,5 (Kimbrough; NCCN, BCC; NCCN, Melanoma; NCCN, SCC)
- Another excision procedure
- Mohs microsurgery
What questions should I ask before an excision operation?
- How will you perform the excision?
- How will you repair the area?
- What will the scar look like?
- What type of anesthesia will you use?
- How wide will the margins be? What is the reason for that?
- What is the chance of recurrence?
- What should I expect for my recovery?
- How will I find out what the pathology report says?
- How often should I have follow-up exams to check for cancer recurrence or a second skin cancer?