Understanding Merkel Cell Carcinoma: What Patients and Families Should Know

Educational Video: Merkel Cell Carcinoma Explained

Merkel cell carcinoma (MCC) is a rare but aggressive type of skin cancer. In a recent symposium with Duke Cancer Institute, Dr. Salam shared important insights about MCC—covering what it is, who it affects, how it’s treated, and what new therapies are offering hope to patients. You can watch all the presentations from the symposium with Duke Cancer Institute by viewing the full symposium videos for patients and families.

What Is Merkel Cell Carcinoma?

Merkel cells are specialized neuroendocrine cells found in the skin’s top layer (the epidermis). They play a role in relaying touch sensation to the brain and in hormone production. When these cells become cancerous, they form Merkel cell carcinoma—a cancer that often appears as a painless, fast-growing lump on the skin.

Who Is at Risk

MCC is a rare cancer, with about 2,500–3,000 cases each year in the United States. However, as Dr. Salama points out, incidence is on the rise.

Risk factors include:

• Older age (it is very rare under age 50, more common over 65–70)
• Significant sun exposure, especially on the head, neck, trunk, and arms
• Fair skin
• A suppressed immune system (though most MCC patients do not have clear immune suppression)
• The Merkel cell polyomavirus, which is present in about half of cases

Diagnosis and Initial Management

Because MCC can be aggressive, patients benefit from care at multidisciplinary cancer centers that bring together dermatology, surgery, radiation oncology, and medical oncology.

Key steps may include:

• Surgery, often with sentinel lymph node biopsy to determine whether the cancer has spread
• Imaging, depending on the clinical situation
• Polyomavirus antibody blood tests for some patients, to help track disease after treatment and guide follow-up

Treatment Advances: The Role of Immunotherapy

Historically, outcomes for advanced MCC were poor, with chemotherapy offering only short-lived benefit. That changed with the arrival of immunotherapy, specifically checkpoint inhibitors.

• Pembrolizumab (Keytruda), a PD-1 inhibitor, has shown high response rates, with many patients experiencing significant and durable tumor shrinkage.
• Avelumab (Bavencio), a PD-L1 inhibitor, is also FDA-approved for MCC, including in patients previously treated with chemotherapy. Those who respond can have long-term survival.

For some patients, dual checkpoint inhibitors or immunotherapy before surgery (neoadjuvant therapy) are being explored in clinical trials, showing promising early results.

Looking Ahead

While progress has been dramatic, MCC remains a serious cancer. Clinical trials are critical to improving outcomes, and treatment at experienced cancer centers is strongly recommended.

Merkel cell carcinoma may be rare, but as Dr. Salama emphasized, the incidence is on the rise—and new immunotherapies are bringing real hope to patients and families.

If you have any questions about skin cancer or your care, our skin cancer nurse expert is here to help.