Ultraviolet rays from the sun — not to mention tanning booths — get the lion’s share of the blame for skin cancer, as they should, experts emphasize. But as with many other conditions, in addition…
Ultraviolet rays from the sun — not to mention tanning booths — get the lion’s share of the blame for skin cancer, as they should, experts emphasize. But as with many other conditions, in addition to the outsized role of UV rays, genetics may also affect a person’s chances of developing skin cancer.
“For nearly all cases of skin cancer, environmental factors seem to play a much larger role than inherited risks,” Dr. Kelly Cha, an assistant professor of dermatology at Michigan Medicine and dermatologist who treats skin cancer patients at the University of Michigan Rogel Cancer Center, noted via email. Still skin cancer is genetic “in that it involves some degree of inherited risk. It’s also genetic in the sense that environmental factors like sun exposure lead to genetic alterations within individual cells, allowing cancer to develop.”
Of primary concern when it comes to skin cancer is melanoma. “Melanoma accounts for only about 1% of skin cancers but causes a large majority of skin cancer deaths,” according to the American Cancer Society. It’s projected that approximately 7,230 people will die this year from melanoma — about 4,740 men and 2,490 women.
“In the case of melanoma, we do think more about inherited risk factors besides background skin pigmentation,” Cha says. “In a small minority (perhaps 5 to 10%) of people with melanoma, there may be some specific genetic change that predisposed them to develop melanoma. These genetic changes can occur in genes like CDKN2A, CDK4, BAP1 and POT1.”
Roughly 90 percent of skin cancer cases are caused by environmental factors — far and away most often UV rays. Less commonly everything from radiation to other types of burns (beyond sunburn) to the human papilloma virus, or HPV, can be the cause. And a small subset are the result of genetic syndromes like basal cell nevus syndrome, or Gorlin syndrome, and xeroderma pigmentosum, which results in extreme sensitivity to sunlight and is usually diagnosed in early infancy, as well as separate genetic changes, or mutations, that commonly go undetected. “About 10% of melanomas are caused by a gene mutation (change) that passes from one generation to the next,” the American Academy of Dermatology notes.
“Typically, a family history of melanoma is considered more meaningful than a family history of basal or squamous cell cancer. The risk of BCC or SCC is quite high in general, so family history of these common skin cancers may not significantly impact our counseling,” Cha explains. “Nonetheless, this information does help us to better understand our patients’ concerns and to recommend sun-protective behaviors and self- and professional skin surveillance when advisable.”
Genetic Testing for Melanoma
“For the vast majority of individuals, the risk of skin cancer is related much more strongly to UV exposure than to identifiable inherited risks,” Cha reminds. “For these individuals, genetic testing is not necessary, would be unlikely to yield a positive result and would not change our approach or recommendations. That said, there are some individuals who could benefit from genetic testing for skin cancer risk.”
According the AAD, genetic counseling and possibly genetic testing for melanoma may be advised by a dermatologist for patients who’ve had at least one of the following:
— Three or more melanomas that have grown deep into the skin (or spread), particularly if a melanoma was diagnosed before a person’s 45th birthday.
— At least three blood relatives on one side of a person’s family who’ve had melanoma or pancreatic cancer.
— Two or more unusual-looking moles that are called Spitz nevi.
— At least one more Spitz nevi and a close blood relative who’s had a type of cancer called mesothelioma, meningioma (a type of brain tumor) or melanoma of the eye.
In certain cases genetic factors may increase a person’s risk for other types of cancer as well as skin cancer. “Sometimes even BRCA genes can be related to developing melanoma,” says Dr. Mona Gohara, a dermatologist and an associate clinical professor of dermatology at the Yale School of Medicine, and fellow of the American Academy of Dermatology. Most notably, BRCA gene mutations are tied to a higher risk of breast cancer. However, where some women go as far as to have mastectomies — or surgery to remove their breasts — as an aggressive prevention measure, there’s no analogous procedure to prevent skin cancer. Rather it’s about close monitoring. “You can’t take off your skin. So it translates into very judicious surveillance of the skin and other organs,” such as the pancreas and lungs, Gohara says.
Additionally, referral for genetic testing may be recommended where an individual has had melanoma and that person or family members have had other cancers, such as pancreatic cancer, thyroid cancer, mesothelioma, breast cancer — especially at a young age or in a male — or kidney cancer, Cha says. “Cancer genetics professionals (counselors and physicians) should be involved in evaluating patients for these tests,” she says.
In addition, individuals who have developed a high number of skin cancers of any type, including basal or squamous cell cancer — or started to develop them from a very young age — may also talk with a dermatologist about whether genetic testing is warranted.
Including any and all types, skin cancer is far and away more common than any other cancer in the U.S. “It’s more common than colon, lung, prostate and breast (cancer) combined,”Gohara points out. “One in 5 Americans are going to get skin cancer.”
Fortunately, it’s far down the list in regards to causes of cancer death. Early detection is key for effective treatment — primarily surgical removal of the cancerous growth. That’s not to say, however, that routine cancer screening is recommended for anyone and everyone. In regards to skin cancer screening, he U.S. Preventive Services Task Forces, an independent group of national experts in prevention, found in 2016 that “evidence is insufficient to assess the balance of benefits and harms of visual skin examination by a clinician to screen for skin cancer in adults .”
“In general, other than in the context of specific cancer predisposition genetic syndromes, it is a person’s individual risk factors (background skin pigmentation, sun exposure, personal history of skin cancer, etc.) rather than family history that are most important in informing our recommendations about how often to get checked,” Cha says.
Along with genetic considerations, risk factors for skin cancer include skin that burns easily, blond or red hair, a history of excessive sun exposure and sunburns, tanning bed use and a weakened immune system, according to the American Cancer Society. Even one bad sunburn or trip to the tanning bed can increase your risk. And tanning beds are now widely recognized as a cause of skin cancer. Sunlamps used in tanning salons have been shown to emit doses of UVA — a type of UV ray — equivalent to many times that of the sun, and research finds use of a tanning bed in childhood or adolescence, in particular, can greatly increase one’s risk for developing melanoma.
Knowing your body — and keeping an eye out for even small changes — is especially important, experts say. Regardless of one’s skin color, the AAD notes that anyone can get skin cancer. “Check your skin head to toe monthly,” Cha suggests. The AAD provides instructions online on doing a full body skin check — back, front and sides — in front of a mirror, and even a downloadable body mole map that you can use to document your self-exam.
“If you have a mole that’s been with you since childhood without significant change, that’s usually a good sign that you don’t need to worry about it. However, a spot that has changed, or one that is new and doesn’t fit in well with others on your skin, needs to be evaluated,” Cha says. “Melanoma can start as a flat, discolored spot, so don’t ignore funny-looking flat spots any more than you would ignore an unusual bumpy spot. Basal cell and squamous cell cancers are more often pink, sometimes scaly, and sometimes with a sore that won’t heal.”
Adds Gohara: “There is kind of a general rule that dermatologists talk about with the ABCDEs of melanoma.” That is, take heed of any of the following — if you see a mole that’s:
— Border is irregular.
— Color is irregular.
— Diameter is getting wider.
— Evolving in any way.
“That’s a great starting point. But I always encourage my patients to really get to know the milieu of the moles and their skin lesions, so that they can identify any minor change,” Gohara says. “And patients are actually really good at that once you empower them to do that.”
If you have any concerns, don’t wait to see a dermatologist.
Preventing Skin Cancer
For the vast, vast majority, the primary risk factor for skin cancer remains unprotected exposure to UV rays. And so, in addition to doing regular skin self-exams, and irrespective of whether genetics raise your risk or not, it’s key to wear sunscreen with an SPF of 30 or higher, limit full sun exposure, avoid tanning beds and take other measures to reduce exposure. That includes, according the AAD:
— Seeking shade as needed, remembering from 10 a.m. to 2 p.m. the sun’s rays are strongest.
— Wearing protective clothing, from a lightweight long-sleeved shirt to a wide-brimmed hat.
— Reapplying sunscreen, when outside, every two hours, or after swimming or sweating.
— Using extra caution around water, snow and sand, which reflect the sun’s rays.
— Considering a self-tanning product (and still wearing sunscreen) if you want to look tan, instead of a tanning bed.
“Beyond shared genes, family members often share similar ultraviolet exposures in terms of outdoor activities (sports, vacation, work, hobbies) and share similar habits like using indoor tanning salons or using sun-protective behavior, such as sunscreen and hats,” Cha notes. “Although these factors aren’t genetic, they definitely contribute to the tendency for skin cancer to ‘run in the family.'”