What’s New in Merkel Cell Carcinoma Research?

Causes of Merkel cell cancer (MCC)

Researchers are learning more about the Merkel cell polyomavirus (MCV), which is found in most MCC tumors.

It’s not yet clear exactly how damage from UV light, infection with MCV, and changes in the body’s immune system might interact to cause MCC, but this is an active area of research.

Prevention and early detection of Merkel cell cancer (MCC)

Most skin cancers, including many MCCs, can be prevented by people limiting their exposure to ultraviolet (UV) rays. The best way to lower the number of skin cancers is to educate the public, especially parents, about skin cancer risk factors and warning signs. It’s important for health care professionals and skin cancer survivors to remind others about the dangers of too much UV exposure (both from the sun and from man-made sources like tanning beds) and about how easy it can be to protect your skin from UV rays.

MCC can often be found early, when small, hasn't spread, and is most likely to be cured. Monthly skin self-exams and awareness of the warning signs of MCCs and other skin cancers can be helpful in finding them early.

The American Academy of Dermatology (AAD) sponsors annual free skin cancer screenings throughout the country. Many local American Cancer Society offices work closely with AAD to provide volunteers for registration, coordination, and education efforts related to these free screenings. Look for information in your area about these screenings or call the American Academy of Dermatology for more information. 

Treatment of Merkel cell cancers (MCC)

While early-stage MCCs often can be cured, more advanced MCCs tend to be much harder to treat. It’s been hard to study the best way to treat these cancers because they're not common. But in recent years, doctors have begun to look at newer types of treatment.

Immunotherapy

This type of treatment helps the body’s immune system attack cancer cells more effectively. Doctors have been hopeful that this approach might be useful against MCC, especially because some of these cancers appear to be linked to infection with the Merkel cell polyomavirus (MCV).

Immune checkpoint inhibitors: In recent years, immunotherapy drugs known as checkpoint inhibitors have been approved for treating advanced MCC. Doctors are now studying if these drugs might be helpful earlier in the course of the disease. For example, studies are looking at whether giving one of these drugs after surgery and/or radiation (known as adjuvant treatment) might lower the risk of the cancer coming back. Doctors are also looking at giving them before surgery (known as neoadjuvant treatment) to try to shrink the cancer and make it easier to remove.

Oncolytic virus therapy: Viruses are a type of germ that can infect and kill cells. Some viruses can be altered in the lab so that they infect and kill mainly cancer cells. These are known as oncolytic viruses. Along with killing the cells directly, the viruses can also alert the immune system to attack the cancer cells.

Talimogene laherparepvec (Imlygic), also known as T-VEC, is an oncolytic virus that can be injected directly into tumors. This treatment is already used to treat some melanomas of the skin, and it's now being studied for use against MCC as well.

Hormone-like drugs

MCC is a type of neuroendocrine tumor, which means its cells share features with cells that normally make hormones in the body. Doctors are testing whether drugs that affect hormone-making cells might be helpful against MCC.

One example is a group of drugs known as somatostatin analogs, such as octreotide and lanreotide. These drugs have shrunk some MCC tumors in early clinical trials.

Another drug being studied is lutetium Lu-177 dotatate (Lutathera). This is a drug linked to a radioactive element. It works by attaching to the somatostatin receptor on cancer cells, allowing radiation to enter the cells and cause damage.

Studies testing these types of drugs against MCC are now under way.

Targeted therapy drugs

Newer drugs called targeted therapies are also being studied to see if they can help treat MCC. Targeted drugs attack parts of cancer cells that make them different from normal cells. Each type of targeted drug works differently, but they all alter the way a cancer cell grows, divides, repairs itself, or interacts with other cells. Targeted drugs are already used to treat many types of cancer, and many are now being studied for use against MCC.

Combining treatments

Studies are looking at treatment combinations that might work better against MCC, especially for cancers that no longer respond to the usual treatments. For example, several studies are looking at combining immunotherapy and chemotherapy drugs.