Merkel cell carcinoma (MCC) is a rare form of skin cancer, but its numbers are climbing.
Also referred to as neuroendocrine carcinoma of the skin, trabecular carcinoma or trabecular cancer, MCC made headlines in September when it was revealed that singer-songwriter Jimmy Buffett, who died Sept. 1 at the age of 76, had received a diagnosis of MCC four years earlier.
MCC affects approximately 2,400 patients in the United States each year, Dr. Manisha Thakuria, director of the Merkel cell carcinoma clinic at the Dana-Farber Cancer Institute and assistant professor of dermatology at Harvard Medical School, told CURE®.
“That number is increasing at a rate of about 8% per year,” she said. “So, it’s a rapidly increasing incidence. However, just to put it into perspective, melanoma, which is the skin cancer that most people have heard of as the dangerous skin cancer, will affect over 100,000 people in 2023, and probably double that number if you include the in situ melanomas, which are fully curable cancers, usually with simple surgeries.
According to the American Cancer Society, MCC, is one of the most dangerous types of skin cancer and is more likely than common skin cancers to spread to other parts of the body and potentially very difficult to treat if it spreads.
Risk factors for MCC, according to the American Cancer Society, include Merkel cell polyomavirus infection, exposure to ultraviolent rays (with sunlight as the main source), light-colored skin and a weakened immune system. It is very rare among people younger than age 50, and approximately 80% of patients with MCC are older than age 70 — and men are almost twice as likely to develop MCC.
Thakuria told CURE®about some of the potential reasons for the increased incidence of MCC:
There’s a lot of speculation and this is something I think about a lot just personally with my patients. I think some of it is probably increased awareness and diagnosis, which is a good thing, right? So, rather than somebody dying of some mysterious unknown neuroendocrine carcinoma, they’re diagnosing it appropriately as Merkel cell carcinoma, and some of those patients are getting to treatment on time, and so the numbers are going up for that good reason.
But, I think also the numbers are truly going up because we have an aging population. This is a cancer of older adults. So, the average age of a person with Merkel cell carcinoma is probably about 74, 75, depending on what study you look at. And we also have, increasingly, a population where patients are immunosuppressed for various reasons.
So, although the majority of patients with Merkel cell carcinoma are not actually immunosuppressed — only about 10% of patients with Merkel cell carcinoma are classically immunosuppressed in a way that we can measure, like they take medications that bring down their immune system for common diseases like rheumatoid arthritis or psoriatic arthritis, or they might be immunosuppressed because of (being) post-transplant so they take medicines again to suppress their immune system for that, and then certain blood cancers can also immunosuppress a patient.
And so, certainly there they are over-represented, that group is over-represented, in Merkel cell carcinoma patients versus the normal population.
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