Merkel cell carcinoma (MCC), a rare form of skin cancer that has no specialized treatment method, is becoming more common, according to a study presented at the American Academy of Dermatology 2018 Annual Meeting in San Diego on Feb. 16 and published in the Journal of the American Academy of Dermatology (Mar. 2018; 78(3):457-463).
“We believe the aging of the U.S. population is likely driving the increase in MCC, as this cancer is much more prevalent in older individuals,” said study author Dr. Paul Nghiem, head of the Division of Dermatology and George F. Odland Endowed Chair in Dermatology at the University of Washington in Seattle, in a press release.
MCC manifests as a firm lump that is red, purple, or skin-coloured. Photo by Klaus D. Peter.
Dr. Nghiem added that weakened immunity in aging populations may play a role in MCC. Incidence rates for MCC increase 10-fold between ages 40 to 44 and 60 to 64 years, and a further 10-fold between ages 60 to 64 and 85 years plus.
Investigators analyzed 6,600 MCC cases from the SEER-18 Database. From 2000 to 2013, the number of reported MCC cases increased by 95%, compared to 57% for melanoma and 15% for other cancerous tumours. Based on current population trends, the researchers predict that MCC incidence will grow to more than 3,200 in 2025 from nearly 2,500 cases in 2013.
MCC is linked to a common virus called Merkel cell polyomavirus that is found on human skin and frequently-touched surfaces. The virus is not associated with any other disease. Most people exposed to Merkel cell polyomavirus do not develop MCC. Diagnosis of MCC is more likely when the virus is encountered by people with compromised immune systems.
A highly aggressive and rapidly growing cancer, early diagnosis is vital for increasing MCC survival rates.
“Compared to melanoma, MCC is much more likely to be fatal, so it’s important for people to be aware of it,” said Dr. Nghiem.