MCC typically appears as a painless pink or purple bump on sun-exposed areas of skin. It usually spreads first to nearby lymph nodes, and may then spread, or metastasize, to lymph nodes or skin in distant parts of the body, lungs, brain, bones, or other organs. (1) Merkel cell cancer tends to grow quickly and spread beyond the skin even in the early stages of the disease, making it a difficult cancer to catch and treat soon enough. It is the second most common cause of skin cancer–related death after melanoma. (1) RELATED: RA Drug Methotrexate Tied to Higher Risk of Skin Cancer, Other Risks Though MCC is much less common than other types of skin cancer — roughly 30 times less common than melanoma — incidence has been increasing quickly, having quadrupled in the past few decades. (3) According to the Skin Cancer Foundation, roughly 2,500 new cases of MCC are diagnosed annually in the United States. (14) Though MCC is very rare, incidence has been rising quickly. A study published in the Journal of the American Academy of Dermatology found that between 2000 and 2013, MCC increased by 95 percent. This trend is expected to continue, with annual incidence reaching 3,250 cases per year by 2025. (15) Some of the uptick in MCC is likely due to the fact that lab tests to diagnose MCC have become more accurate. But it might also be caused by increases in risk factors. More people are living longer, and many people over age 65 did not regularly protect their skin from the sun. (4) RELATED: The Difference Between Chemical and Mineral Sunscreen With early detection and treatment, MCC can be well contained and often cured. Treatment becomes more difficult as the tumor grows and spreads. That’s why it’s critical to recognize this cancer in its earliest stage. Common characteristics of MCC:

They appear as a single bump located on the face, head, neck, or arms.They are often firm and dome shaped or raised.They are frequently pink, red, or purple in tone.They are painless.They are fast growing, usually becoming notably bigger in a few weeks to months.

RELATED: Is It Toenail Fungus or Something Else? MCP lives on the skin of most people without any signs or symptoms — and without ever developing into MCC. Just how this virus triggers a dangerous skin cancer in some people and not others has yet to be determined, but researchers have identified a number of factors that markedly increase your risk. These include:

Excessive Exposure to UV Light Chronic exposure to light from the sun or tanning beds damages the DNA of genes that control skin-cell growth. This puts you at risk of all skin cancers — and MCC is no exception. The vast majority of MCCs appear on skin surfaces that are frequently exposed to the sun.Older Age Though MCC can occur at any age, your risk significantly increases as you get older. More than half of MCC patients are over the age of 65 years at the time of diagnosis. The average age of diagnosis is 74. (6)A Weakened Immune System If your immune system is suppressed (as a result of HIV infection, chronic leukemia, or immunosuppressive drugs), you are about 15 times more likely to develop MCC than people with healthy immune function. (7)Light Skin Color More than 9 out of 10 cases of MCC in the United States are diagnosed in whites. (7)

RELATED: Cancer Risk Genes: Everything You Need to Know About ATM If MCC is found, your doctor will perform additional tests to determine whether the cancer has spread to other parts of the body, a process known as staging. These tests may include:

A sentinel lymph node biopsy, to see if the cancer has spread to nearby lymph nodes.Diagnostic imaging tests, such as an X-ray, computed tomography (CT) scan, or positron emission tomography (PET) scan, of your body to find out if the cancer has spread to other organs.

RELATED: Many DIY Sunscreens on Pinterest Don’t Work, Study Suggests The earliest stage Merkel cell cancers are called stage 0 (or carcinoma in situ), and then range from stages 1 through 4. Generally, the lower the number, the less the cancer has spread. Some stages are also subdivided by letter; an earlier letter means a lower stage. (8) The stage of your MCC at diagnosis determines the chance for later spread, as well as your treatment plan. RELATED: 10 Sun-Care Products That Dermatologists Use For regional MCC (when the cancer has spread outside the skin to nearby lymph nodes or other structures), the five-year survival rate falls to 51 percent. If MCC has spread to distant organs, the survival rate is 17 percent. (9) Overall, about one third of MCC patients succumb to the disease. (3) While survival rates can give you an idea of how long people live based on what stage their cancer was at diagnosis, they can’t tell you how long you will live. Other factors, such as your age and overall health, as well as how well the cancer responds to treatment, also play a significant role in your prognosis. Moreover, current survival statistics are based on outcomes of people diagnosed with MCC between 2008 and 2014. Thanks to new and better treatments, people now being diagnosed with MCC may have a much better outlook. (9) If the MCC has spread to the lymph nodes, then either radiation (which uses high-energy beams, such as X-rays and protons, to kill cancer cells) or surgery to remove the nodes is recommended. Radiation therapy is also sometimes used after surgery to destroy any cancer cells that remain after the tumor is removed. For advanced MCC, immunotherapy — which helps the body’s own immune cells recognize and destroy cancer cells — is rapidly becoming a preferred systemic treatment. One class of immunotherapy drugs, called checkpoint inhibitors, are showing particular promise in the treatment of MCC. Checkpoint inhibitors turn on the immune system by blocking an inhibitor (a “checkpoint”) that normally restrains the immune system. Studies suggest that checkpoint inhibitors can help shrink MCC tumors in many patients and that responses, when they occur, tend to be long lasting. (10) Two checkpoint inhibitors are currently available for patients with MCC:

avelumab (Bavencio)pembrolizumab (Keytruda)

A number of other promising immunotherapy treatment approaches, including other checkpoint inhibitors and infusions of immune cells (T cells), are also being investigated for MCC in clinical trials. Researchers are also studying the use of hormone-like therapies, targeted therapies, and different combinations of therapies for the treatment of MCC. (11) To learn more about active MCC clinical trials, their eligibility and location sites, visit the NIH’s website. RELATED: A Consumer’s Guide to Clinical Trials

Limit UV exposure. You can practice prevention every day by wearing protective hats and clothing, avoiding the midday sun and tanning beds, and using broad-spectrum sunscreen with an SPF of at least 30 even on cloudy days. Reapply sunscreen every two hours when swimming or sweating.Keep an eye out. MCC lesions don’t have the dramatic look or color of other skin cancers. That’s why it’s so important to closely examine your skin from head to toe once a month. If you notice a new or unusual spot or a raised bump that seems to be growing, contact your doctor right away.Get screened. See a dermatologist once every year for a professional skin exam.

If you’ve been treated for MCC, also be sure to:

Follow up regularly with your dermatologist once treatment is complete. Stick to the exam schedule your doctor recommends — it’s the best way to quickly detect a recurrence.Play close attention to the site and surrounding region. MCC can return suddenly. Contact your medical team immediately if you see any suspicious changes.Consider getting the blood test that can help pick up recurrences early. The Merkel polyomavirus serology test measures antibodies to the Merkel polyomavirus in the blood. It can help pick up recurrences of MCC early, when they can be most effectively treated. (12,13)

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