Skin cancer takes many forms
Late last month, doctors removed a cancerous growth from Gov. Jerry Brown’s nose. The diagnosis was basal cell carcinoma, a common skin cancer that is very treatable and only rarely spreads elsewhere in the body. It is not the same as melanoma, which is a less common but deadlier skin cancer.
“I think one of the biggest misunderstandings about skin cancer is the difference between melanoma and non-melanoma,” says Dr. Lisa Chipps, an L.A.-based dermatologist and educational spokeswoman for the Skin Cancer Foundation, a national awareness group based in New York City.
Here’s a closer look at the different types of skin cancers, how they’re detected and treated, and how to prevent them.
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What are the different kinds of skin cancer?
Non-melanoma skin cancers include basal cell carcinoma -- the type that Brown had and the most common form of skin cancer -- and squamous cell carcinoma. They arise in skin cells called keratinocytes and can begin as any of a number of skin imperfections, such as a scaly red patch that might look rash-like or a waxy bump that might be red or white. More than 2 million people in the U.S. are diagnosed with non-melanoma skin cancers every year, according to the American Cancer Society. They account for just 0.1% of deaths from all cancers.
Melanomas occur far less frequently but can strike young -- they’re the leading cancer in young adults ages 25 to 29. Arising from the pigment-making cells of the skin, the melanocytes, they show up either as new dark-colored marks or moles on the skin or changes in existing moles. The Skin Cancer Foundation recommends that people stay aware of potentially troublesome signs by minding the ABCDEs of moles: Asymmetry, Border irregularity, Color variation, Diameter larger than a pencil eraser, and Evolving or changing over time.
About 114,900 new cases of melanoma were diagnosed in 2010, and more than half of them were invasive, meaning the cancer had traveled to other parts of the body. Five-year survival rates for invasive melanoma are just 15%, compared with 98% when the cancer is localized.
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How are skin cancers diagnosed?
A dermatologist may use a magnifying glass or polarized light to better see the details of suspect marks. But to definitively diagnose a skin cancer, doctors take a biopsy and study the cells under a microscope.
Although skin cancer can occur in any person of any race, certain people are at higher risk of developing skin cancer and may want to get screened periodically. Men are at somewhat higher risk than women, and whites have 10 times the risk of African Americans. People with freckles and who easily burn are at the highest risk. Other risk factors include a history of sun (or tanning bed) exposure or of childhood sunburns, especially ones that blistered.
There are no universally agreed-on guidelines for who should get screened, at what age or how often, Chipps says. She recommends screening for people who have a lot of moles or very fair skin or a family history of melanoma. Many organizations, such as the Skin Cancer Foundation ( www.skincancer.org), the American Academy of Dermatology ( www.aad.org) and the American Society for Dermatologic Surgery ( www.asds.net), periodically offer free full-body screenings in many U.S. locations.
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How are skin cancers treated?
Non-melanomas are usually cut off surgically or frozen off with liquid nitrogen. Sometimes creams, such as 5-fluorouracil or imiquimod, are prescribed for superficial cancers, to be applied over a period of weeks. They are easy to use and less disfiguring than surgery, but they have a lower cure rate.
Brown underwent Mohs surgery, which is the gold standard for removal of non-melanoma cancers, Chipps says. The technique is used for cancers that are large-sized, recurrent or on certain parts of the body, such as the nose, ears and scalp.
In Mohs surgery, a doctor will take out all the cancer he or she can see, Chipps says. Then the doctor will take very thin layers from the surgical site’s edges, which are examined while the patient waits, and will continue to remove tissue until it no longer shows cancer. “With this method, there’s a 99% cure rate,” she says. If necessary, reconstructive surgery is done to repair the wound.
Melanomas that haven’t spread can be removed surgically. Patients whose melanoma has spread should see an oncologist with experience in treating these advanced cancers.
Melanomas are notoriously resistant to most chemotherapeutic drugs, but new treatments are energizing the field, says Dr. Antoni Ribas, a oncologist and researcher with UCLA’s Jonsson Comprehensive Cancer Center. “These new therapies are based on a better molecular understanding of the cancer,” he says.
Yervoy, which was approved by the Food and Drug Administration in March, is an immunotherapy that helps the body’s own defenses fight cancer cells. In clinical trials, patients for whom other treatments had failed lived an average of 10 months after starting Yervoy, compared with 6.5 months for those who received another immune stimulant drug. In addition, 20% of patients who took Yervoy lived at least two years.
A second drug, called PLX4032, turns off a genetic switch that is abnormally activated in cancer cells and causes them to divide uncontrollably. This mutation, in a gene called BRAF, occurs in about half of all melanomas; the drug blocks the product of that gene. In one early clinical trial, 80% of patients responded to the experimental drug and their tumors shrank. Larger clinical trials are in progress in order to obtain FDA approval.
The results are very impressive, Ribas says, but the gains don’t seem to last forever: “Unfortunately, the melanoma figures out a way to turn [the gene] on again -- or to turn on another switch.”
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What steps can you take to reduce your risk of skin cancer?
Understand that ultraviolet radiation from the sun is a carcinogen, Chipps says. The link between sun exposure and non-melanoma skin cancer is very strong; it is less so for melanoma. Minimize exposure by avoiding the midday sun, particularly between 10 a.m. and 4 p.m. Don’t use tanning beds. Use sunscreen that is at least SPF 15 and protects against UV-A and UV-B. Wear protective clothing such as hats and UVR-rated clothing.
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