Surgery for Merkel cell carcinoma
Surgery is the main treatment for most Merkel cell carcinomas (MCCs).
Initial skin biopsy
In many cases, a skin biopsy is done to remove a suspicious spot even before the doctor suspects it might be MCC (see “How is Merkel cell carcinoma diagnosed?”). This can be thought of as a type of surgery (especially if an excisional biopsy is done), but it’s not considered adequate treatment for MCC. If MCC is diagnosed from the biopsy, a wide excision (described below) is used to remove more skin and other tissues in the area.
Sentinel lymph node biopsy (SLNB)
Even in people who have MCC with no obvious spread of the cancer to nearby lymph nodes (or distant organs), about 1 out of 3 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 “How is Merkel cell carcinoma diagnosed?”) is typically a very important part of determining the stage of the cancer.
Whenever possible, it’s important that the SLNB be done before a wide excision is used to remove more skin and other tissues from the main tumor site. This helps ensure the results of the SLNB are accurate.
If the SLNB result is negative (that is, if the sentinel node does not contain cancer cells), no more lymph node surgery is needed because it’s very unlikely the cancer would have spread beyond this point (although radiation therapy might still be given to the nearby lymph nodes just in case).
If cancer cells are found in the sentinel node, the remaining lymph nodes in this area are often removed and looked at, too. This is known as a lymph node dissection (see below). Radiation therapy might be given to the area after the lymph node dissection. (In some cases radiation might even be used instead of doing a lymph node dissection.)
When a diagnosis of MCC is made by skin biopsy, the tumor site will most likely need to be excised (surgically cut out) again to help make sure the cancer has been removed completely. This fairly minor surgery might cure MCC if it hasn’t spread beyond the skin.
Local anesthesia is injected into the area to numb it before the excision. The surgeon then cuts out the tumor site, along with some normal skin at the edges. The normal, healthy skin around the edges of the cancer is called the margin. The skin is carefully stitched back together afterward. This will leave a scar.
The removed tissue sample is then sent to a lab, where it is viewed 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. The margins are wider (usually at least 1/2 inch). 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 might need to be altered based on where the cancer is on the body and other factors. For example, 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.
If the cancer is on a finger or toe and has grown deeply, the treatment might require amputation of all or part of that digit.
Mohs micrographic surgery
Mohs surgery is sometimes used when the goal is to save as much healthy skin as possible, such as with cancers around the eye. It’s done by a doctor with special training in this approach.
Using the Mohs technique, the doctor removes the tumor and a margin of normal appearing skin and then checks the sample under a microscope. If cancer cells are seen at the edges of the sample, another layer of skin is removed and examined. This is repeated until the skin samples are free of cancer cells. This process is slow, often taking several hours, but it allows more normal skin near the tumor to be saved.
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 another type of biopsy), a lymph node dissection is usually done.
In this operation, the surgeon removes all of the lymph nodes in the region near the primary tumor. For example, if the MCC is found on an arm, the surgeon would remove the nodes in the underarm region on that side of the body, which is where cancer cells would be most likely to travel first.
This type of surgery is done in an operating room and requires general anesthesia (where you are in a deep sleep). 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 usually be helped with medicines, if needed.
A full lymph node dissection can also 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 severe enough, it can cause skin problems and an increased risk of infections in the limb. Elastic stockings or compression sleeves can help some people with this condition. For more information, see Understanding Lymphedema (for Cancers Other Than Breast Cancer). (Sentinel lymph node biopsy is less likely to cause this problem.)
Skin grafting and reconstructive surgery
After removing large skin cancers, 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.
Last Medical Review: 04/13/2015
Last Revised: 02/09/2016