Merkel Cell Carcinoma--Melanoma’s Adopted Brother

​A friend of mine is presently being treated for Merkel cell carcinoma and began radiation about a month ago, so I thought I might write a little about this form of skin cancer. Your first thought might be, “What is a Merkel cell? I’ve never heard of it.” Merkel cells lie on the outermost layer of the skin. They were identified in the 1800’s by Friedrick Merkel, a German anatomist. Their complete function has not yet been identified but they are found all over the body in varying amounts, with the highest density on the fingertips, lips, and face where touch sensitivity is at its greatest. They have also been found to produce hormones, although the function of this capacity is still unknown. So this is still very new territory.
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Merkel cell carcinoma has been rare but, as with melanoma, the number of occurrences has been increasing rapidly in recent years. Diagnosis can be a little random since doctors are rarely looking for it when it is found. Most of the time it is discovered when a biopsy is being performed for another form of skin cancer and it turns up. It is a like going for a walk and hearing hoof beats behind you. You turn to look at the horse you expected but instead you find a zebra. An early diagnosis can mean minimal treatment and an assurance of being cured. But it is aggressive and can metastasize in its early stage.

The cause of Merkel cell carcinoma is still a mystery, though a few pieces of the puzzle are beginning to come to light. As with melanoma, sunlight is a factor in its growth, yet another reason to follow the safety precautions we recommend with melanoma prevention. Patients with suppressed immune symptoms are at a greater risk of developing this particular cancer as well. Those whose tumors contain more killer T cells and those whose immune systems are able to heal their primary tumor without intervention tend to fare better. In 2008 a common virus, polyomavirus, was found in a vast majority of Merkel cancer cells, at least 80% of the time. This virus rarely causes any symptoms other than in those cases where it contributes to triggering the MCC.

Treatment options are not dissimilar to those for melanoma. When the risk of the tumor spreading is relatively low, surgery alone can be all that is recommended, although a series of radiation treatment sessions is often added to insure the risk of local recurrence is minimized. It may be possible to remove the tumor with a Mohs micrographic surgery when on the face and there is a need to limit the margin it 1 cm. Since such a small margin is taken, radiation is almost always recommended in this case. Chemotherapy can be used initially but MCC develops resistance to these drugs very rapidly. Immune therapy began to advance about 10 years ago and over the last five years a version of immunotherapy using immune checkpoint inhibitors has shown the best results when skin cancer of any kind metastasizes. There are presently four checkpoint inhibitor drugs available for use, which can be used individually, in conjunction with the others, or in conjunction with other treatments.
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The prognosis and chances of beating the disease are unique to each individual. Early detection and the state of a person’s immune system are key contributing factors to chances of survival.

--Robin Zimmerman
   Sol Survivors Oregon
www.wearesolsurvivors.org

Resources: https://www.merkelcell.org/

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