Understanding Skin Cancer and How to Prevent It
Kelly B. Cha, M.D., Ph.D., a Michigan Medicine dermatologist and skin cancer expert, answers questions about how to best detect and prevent skin cancer
What is the difference between melanoma and other skin cancers, like basal cell and squamous cell carcinoma?
Basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma each arise from different cell types in the top layer of the skin. BCC and SCC are far more common than melanoma, and also less dangerous. Each year, over 2 million people in the U.S. are diagnosed with BCC and SCC. When detected and treated early, nearly all BCCs and SCCs can be cured. In comparison, approximately 139,000 people will be newly diagnosed this year with melanoma – the most deadly form of skin cancer. Unfortunately, melanoma has a greater tendency to aggressively spread (metastasize) beyond the skin, to lymph nodes and internal organs. Thankfully, however, the vast majority of melanomas are caught early and cured.
What do skin cancers look like?
BCC and SCC are usually raised pink areas that are scaly, shiny, crusted, or non-healing. These are most common on the sun-exposed surfaces of your body. Melanoma is typically brown, black, or multicolored. Melanoma usually starts as a flat spot, and in some cases stays that way for months or years, but eventually it will turn into a bump. The most common areas for melanoma are also the sun-exposed surfaces, but you can develop melanoma anywhere at all on the skin surface, so don’t neglect a worrisome spot even if it’s somewhere unusual like the bottom of your foot. In general, skin cancer grows with time. There are many completely benign skin spots that can resemble skin cancer, but if you have any question, the best approach is to get your skin checked by a professional.
What can you do to catch skin cancer early?
Keep an eye out for changes in your skin: new or changing spots (these may be flat or raised), or a spot that itches, bleeds, or won’t heal. Make a habit of regularly checking your entire skin surface from head to toe, perhaps once a month. You don’t have to memorize each spot, just get familiar with the types of spots you have so that you’ll spot an "ugly duckling" (a spot that doesn't fit in with the rest) more easily. Once you get used to it, a thorough exam will take only a few minutes. To help guide your self-exam, check out the UM Comprehensive Cancer Center’s Skin Cancer Screening Card: Be Smart About Your Skin, Know Your ABCDs and the UMSkinCheck App. Be sure to have anything you think is suspicious checked out by your dermatologist, and consider having an annual skin check completed by your dermatologist or primary physician.
How much do factors like sun exposure, ethnicity, and age affect an individual’s risk of skin cancer?
A person's lifetime exposure to UV rays – from sunburns, tanning booths, and chronic sun exposure – is a major risk factor for all types of skin cancer. Those with fair skin are at higher risk because they have less pigment in their skin to protect them from damaging ultraviolet rays. However, it is really important for those with more darkly pigmented skin to know the signs of skin cancer and check their skin too, because although at lower risk, they are not immune. In terms of age, those with older skin have accumulated more damage from the sun, and BCC and SCC typically affect individuals who are middle-aged or older. Melanoma is more "equal-opportunity." We see cases throughout life, including in the late teens or early 20s, especially in young women who have used indoor tanning.
What measures can we take to protect ourselves, especially during the sunnier summer season?
Since UV exposure increases your risk for all skin cancers, it's helpful to put something between the sun and your skin. Choose what works best for you. For some, that's a roof! But even those of us who worry about skin cancer professionally still enjoy being outdoors. Take advantage of shade, an umbrella at the pool or beach, a hat (broad-rimmed is better than a baseball cap to protect your ears and neck), sunglasses, keeping your shirt on while mowing, and so on. If you know your skin will be exposed, I recommend broad-spectrum SPF 30 sunscreen. Don't be stingy with applying the sunscreen – you have to use a generous layer to achieve the SPF on the label. Reapply the sunscreen every couple of hours if you’ll be outside for a long time, and more often if you're swimming or sweating. Nowadays it even comes in convenient forms like sprays if you don't like applying it with your hands.
Finally, please avoid tanning booths. Although they may help you avoid a painful sunburn, they do not protect you from the damage the ultraviolet rays are doing to your skin, and they increase the risk of melanoma, not to mention the risk that you will start looking much older than your age. It's better to use a spray tan or bronzing lotion to achieve the color you wish, and then use sunscreen to protect yourself from the ultraviolet rays.
What about people who have spent years in the sun getting burned and tanned. Does it make sense to be careful in the sun now?
It's true that previous sunburns (or indoor tanning booths/beds) increase the risk that you'll get skin cancer someday. You can't completely erase the damage they may have done to your skin. However, if you are more careful now, you're doing your skin a big favor. You will be less likely to encounter the "final straw" that turns damaged skin cells into cancerous ones. Don't beat yourself up for what's in the past. Just focus on keeping your skin healthy now, and check your skin regularly so that if cancer turns up, you can catch it early when it's far easier to treat and cure.