Surgery for Merkel Cell Carcinoma

Surgery to diagnose or help stage the cancer

Some sort of surgery is often needed to diagnose MCC or find out if it has spread.

In many cases, a skin biopsy is done to remove a suspicious spot even before the doctor suspects it might be MCC (see Tests for Merkel cell carcinoma). This can be thought of as a type of surgery, but it’s not enough by itself to treat MCC. If MCC is diagnosed from a biopsy, a wide excision (described below) is used to remove more skin and other nearby tissues.

Even among people who have MCC with no obvious spread to nearby lymph nodes (or distant organs), about 1 out of 3 people will have cancer cells in their lymph nodes when the nodes are looked at with a microscope. Because of this, a sentinel lymph node biopsy (described in Tests for Merkel Cell Carcinoma) is usually an important part of determining the stage of the cancer. The results of the SLNB are also helpful when planning treatment and discussing outcomes.

It’s important that the SLNB be done before a wide excision (or another type of surgery) is used to remove more skin and other tissues from the main tumor site. This helps ensure the lymph drainage is intact so the results of the SLNB are accurate.

If the SLNB is negative (that is, the sentinel nodes do not contain cancer cells), no more lymph node surgery is needed, because it’s very unlikely the cancer would have spread beyond this point. But if a person has risk factors that make it more likely the cancer will return in the nearby lymph nodes, radiation therapy might still be given to the area, just in case.

If cancer cells are found in the sentinel node(s), the other nearby lymph nodes are often taken out and checked, too. This is called a completion lymph node dissection (see below). Another option might be to give radiation therapy to the area instead of doing a lymph node dissection.

Surgery to treat the cancer

Wide excision

When a diagnosis of MCC is made by skin biopsy, more of the tumor site will most likely need to be cut out (excised) to help make sure the cancer has been removed completely. This surgery might cure MCC if it hasn’t spread beyond the skin.

First, drugs to numb the area (local anesthesia) are put into the skin with a small needle (injected) before the excision. The surgeon then cuts out the tumor, along with some of the normal skin at the edges (including below the tumor). This normal, healthy skin around the edges of the tumor is called the margin. The skin is stitched back together afterward. This will leave a scar.

The removed tissue sample is then sent to a lab, where it's tested and checked with a microscope to make sure that no cancer cells are at the edges of the skin that was removed.

Wide excision differs from an excisional biopsy used to diagnose MCC. The margins are wider. This is because the diagnosis is already known, and the doctor is trying to be sure all of the cancer cells are removed.

The margins can also vary based on where the cancer is and other factors. For instance, if MCC is on the face, the margins may be smaller to avoid large scars or other problems. Smaller margins may increase the risk of the cancer coming back, so be sure to discuss the options with your doctor.

Amputation

In rare cases where the cancer is on a finger or toe and has grown deep into the skin, part or all of that digit might need to be removed (amputated).

Mohs micrographic surgery (MMS) and related techniques

Mohs surgery is sometimes used when the goal is to save as much healthy skin as possible, such as with cancers on the face or ears. It’s done by a doctor with special training.

Using the Mohs technique, the skin (including the tumor) is removed in very thin layers. Each layer is then quickly frozen and looked at with a microscope. If cancer cells are seen, another layer of skin is removed and examined. This is repeated until a layer shows no signs of cancer. This process is slow, often taking several hours, but it allows the doctor to save the normal skin near the tumor.

Mohs surgery is the most common type of micrographic technique (sometimes called peripheral and deep en face margin assessment or PDEMA), but there are others. Other techniques might differ slightly in how the surgery is done, how the tumor samples are processed, or how long the procedure might take. But they all allow the doctor to check the edges (margins) of the removed tumor sample and then remove more layers of tissue if needed.

Lymph node dissection

MCC often spreads to nearby lymph nodes. If cancer is found in the nearby lymph nodes (on a sentinel lymph node biopsy or any other type of biopsy), a lymph node dissection is often done.

In this operation, the surgeon removes all of the lymph nodes near the primary tumor. For instance, if the MCC is found on an arm, the surgeon would remove the underarm (axillary) lymph nodes on that side of the body. These nodes are where cancer cells would be most likely to travel first.

This type of surgery is done in an operating room, where medicines are used to put you into a deep sleep (general anesthesia). As with any major operation, complications can include reactions to anesthesia, bleeding, blood clots, and infections. Most people will have soreness or pain for some time after surgery. This can be helped with medicines, if needed.

A full lymph node dissection can cause some long-term side effects. One of the most troublesome is called lymphedema. Lymph nodes in the groin or under the arm normally help drain fluid from the limbs. If they are removed, fluid could build up. This can cause limb swelling, which may or may not go away. If it's severe enough, it can cause skin problems and an increased risk of infections in the limb. (A sentinel lymph node biopsy is less likely to cause this problem.) Talk to your doctor about your risk of lymphedema. It’s important to know what to watch for, and to take the steps to help reduce your risk.

For more on this, see Lymphedema.

Skin grafting and reconstructive surgery

After removing large skin tumors, it may not be possible to stretch the nearby skin enough to stitch the edges of the wound together. In these cases, healthy skin may be taken from another part of the body and grafted over the wound to help it heal and look better after surgery. Other reconstructive surgical procedures can also be helpful in some cases.