Merkel Cell Carcinoma Diagnosis & Treatment

Memorial Sloan Kettering Cancer Center has the largest single-center experience with Merkel cell carcinoma of anywhere in the world. Our team includes practice-leading experts in surgery, pathology, radiation oncology, and medical oncology who use advanced diagnostic techniques and provide state-of-the-art surgical procedures and other therapies to treat Merkel cell carcinoma.

Merkel Cell Carcinoma Diagnosis

The following tests are used to identify Merkel cell carcinoma and to determine its stage (how far the disease has progressed).

Biopsy

In this procedure, all or part of the tumor is removed for examination by a pathologist. MSK pathologists examine the tumor cells under a microscope or study the proteins or gene abnormalities in the cells to make an accurate diagnosis.

CT or PET Scan

Diagnostic imaging of the entire body is usually performed in patients if there is evidence that the cancer has spread to the lymph nodes. These imaging tests can help determine whether the disease has spread to other areas of the body.

Merkel Cell Carcinoma Treatment

Merkel cell carcinoma is frequently curable with surgical and nonsurgical therapies, particularly if caught early. Treatments are often highly individualized, depending on a patient’s general health, as well as the tumor’s location, size, depth, and degree of spread.

Patients with Merkel cell carcinoma are usually first treated with surgery. Patients with more advanced disease may receive additional treatments such as radiation and drug therapy after or instead of surgery.

Surgery

Surgery to remove the primary tumor is the most common initial treatment for Merkel cell carcinoma. The surgeon typically removes a safety margin of up to 1 inch of normal skin around the tumor to ensure that all cancer cells have been removed.

Surgery may be the only treatment needed if the tumor is small and a wide margin of skin and soft tissue can be removed.

Surgical removal of the tumor is usually done at the same time as a sentinel lymph node biopsy, which determines if the cancer has spread to nearby lymph nodes.

Reconstruction After Surgery for Skin Cancer

Any form of surgery can leave a scar, some more noticeable than others. When removal of a Merkel cell carcinoma leaves a wound that is too large to close with simple sutures, MSK surgeons can use skin grafts, flaps, and other reconstructive procedures to help heal the skin and restore its appearance.

Sentinel Lymph Node Biopsy

This low-risk procedure involves injecting a radioactive material at the tumor site, where lymphatic channels carry it to the sentinel node — the first lymph node to which cancer cells will spread if they were going to spread. For example, tumors of the leg usually spread first to the groin. The sentinel node is then removed and examined to determine whether cancer cells are present. Researchers at MSK were among the first to publish the use of sentinel lymph node mapping for Merkel cell carcinoma.

If the biopsy indicates that the cancer has spread to the sentinel lymph node, most patients are offered radiation therapy. Spread to lymph nodes is found in more than one-third of patients.

Radiation Therapy

Localized radiation therapy can be used to destroy any remaining cancer cells following surgery. Radiation can also be used to treat the area surrounding lymph nodes. Radiation therapy delivers penetrating beams of high-energy particles to the cancer cells and a small margin around the tumor. Radiation therapy can also be used to treat patients who are not candidates for surgery because of ill health or the location of their tumor, or to treat tumors that have returned after an initial round of treatment.

Medical Therapy

A variety of drugs can be used to treat Merkel cell carcinoma. Chemotherapy was traditionally used, but in recent years, immunotherapy has emerged as the most effective strategy to treat patients with more advanced Merkel cell carcinoma. Immunotherapy is most often used for Merkel cell carcinoma in combination with surgery, radiation therapy, or both. It may also be used on its own when surgery and radiation therapy are not possible.

Research studies are ongoing to determine if immunotherapy may be helpful in reducing the risk that the cancer will return in people with earlier stages of Merkel cell carcinoma.

Follow-Up Care for Merkel Cell Carcinoma

Even after successful treatment, Merkel cell carcinomas can often come back. After your initial treatment, your doctor will discuss your specific risk of recurrence and outline a structured plan of follow-up. This plan will include clinic visits and may also include radiologic studies, such as PET scans or CT scans. Individuals who have been treated for Merkel cell carcinoma should see their doctor immediately if they find a growth, bump, spot, or any changes in their skin that could indicate a recurrence of disease. Also, people who have one skin cancer are at a higher-than-average risk for developing new skin cancers of all types.