If you're old enough to remember when nothing stood between you and the sun but a bathing suit and baby oil, you're at risk for skin cancer. If you've always included sunscreen in your beach bag, consider yourself lucky. According to the Skin Cancer Foundation (SCF), 1 in 5 Americans will get skin cancer, a disease that kills about 11,000 people a year. Ninety percent of all skin cancer cases are caused by sun and ultraviolet exposure. That's a terrible price for a day in the sun.

Types of skin cancer

The medical term for "skin" is epidermis. Squamous cells make up the top layer. Basal cells are underneath. Melanocytes are pigment cells (skin color). Skin cancers are divided into two camps: nonmelanoma and melanoma. The most common nonmelanoma carcinomas (cancers) are basal and squamous cell. Cancer of the melanocytes is melanoma.

Ultraviolet rays and sunshine damage skin cells. Some changes are no big deal, but others, like actinic keratoses, can be dangerous. Actinic keratoses are scaly, crusty skin growths. According to the SCF, they are considered precancerous because up to 10 percent of them may become squamous cell carcinoma. How do you know what's trouble and what's not? Only your dermatologist (skin doctor) knows for sure.

Let's take a look at the different kinds of skin cancer and learn how to prevent them.

  • Basal cell carcinoma (BCC): It's the most common skin cancer, the easiest to treat and the least likely to spread. Dr. Katherine Morris, surgical oncologist at Legacy Good Samaritan Hospital in Portland, Oregon, says: "While they probably won't kill you, they can get really ugly. They usually grow on sun-exposed, visible skin—the trunk, face, arms and legs."
  • Squamous cell carcinoma (SCC): This is the second most common form of skin cancer. Each year, there are more than 250,000 new cases and about 2,500 deaths from it. Dr. Morris says, "If they're caught early, they don't cause much trouble but can be very disfiguring."
  • Melanoma: It's the most dangerous form of skin cancer, but in the early stages it has a high cure rate. Dr. Morris says, "If it spreads beyond lymph nodes into surrounding tissues and organs, the chance of cure is slim." The National Cancer Institute (NCI) reported 68,720 new cases of melanoma and 8,650 deaths in 2009.

What causes skin cancer?

We used to think childhood sun exposure was the major cause, but recent studies from the SCF show that people get a fairly consistent dose of ultraviolet radiation over their entire lifetime. Fortunately, we now know how to reduce UV exposure. Unfortunately, skin cancer rates, especially among young women, are spiking. Tanning beds are to blame. The SCF reports, "Frequent tanners using new high-pressure sunlamps may receive as much as 12 times the annual UVA dose compared to ... sun exposure."

According to Dr. Morris: "There's no such thing as a safe tan. I had a 26-year-old patient [a "tanner"] diagnosed with stage 3 melanoma right before her wedding. We had to cut a huge chunk out of her leg and remove lymph nodes. Her leg became chronically swollen. Young people find death very abstract. Scarring and swelling make a bigger impression."

Those most at risk

According to the SCF, men are more likely to get skin cancer than women. Men spend an average of 10 more hours per week in the sun, mainly due to outdoor work and sports, and also tend to use less sunscreen than women do. Also, a 2001 study by the American Academy of Dermatology found that middle-aged and older men are the least likely to do self-exams to check their skin or visit a dermatologist.

Seniors are more likely to get skin cancer because they've had more years in the sun. The National Institutes of Health says: "A person's risk of skin cancer is related to lifetime exposure to UV radiation. Most skin cancer appears after age 50, but the sun damages the skin from an early age."

Make no mistake—everyone can get melanoma. Just how likely you are to get it depends on sun exposure, how many moles you have, genetics, your history of sunburns, previous skin cancers or precancerous growths and your immune system.

Prevention

"The only way to prevent skin cancer is to prevent blistering sunburns and avoid excessive sun exposure," says Dr. Morris.

Tips from the Skin Cancer Foundation include:

  • Stay in the shade between 10 a.m. and 4 p.m.
  • Apply 1 ounce (2 tablespoons) of SPF 15 (or greater) sunscreen to your entire body 30 minutes before going outside. Reapply every two hours.
  • Keep yourself covered with long sleeves and a hat.
  • Get annual skin checkups with a doctor.
  • Examine your own skin monthly.

Self-exams

The SCF describes how to do a self-examination to check every inch of your skin for changes.

The SCF lists these warning signs for skin cancer:

  • A skin growth that grows in size and looks pearly, translucent, tan, brown, black or multicolored
  • A mole, birthmark, beauty mark or any brown spot that:
    • changes color
    • grows in size or thickness
    • changes in texture
    • is uneven in outline
    • is bigger than 6 millimeters or 1/4 inch, the size of a pencil eraser
    • appears after age 21
  • A spot or sore that continues to itch, hurt, crust, scab, erode or bleed
  • An open sore that does not heal within three weeks

If you find something that worries you, schedule a complete head-to-toe exam with a dermatologist. The doctor may do a biopsy of the suspect blemish.

Treatment

How skin cancer is treated depends on what kind of skin cancer it is and how big it is. If the biopsy removed the whole cancer, you might not need further treatment. If you need more treatment, it might include freezing, surgery to remove more tissue, laser therapy, radiation, chemotherapy or other procedures. With melanoma, Dr. Morris says, "We take [out] a big shark bite to make sure all margins around the cancer are clear. It's not pretty."

Beyond the sun

If skin cancer isn't enough to chase you into the shade, Dr. Morris says, "The sun is also responsible for wrinkles." Instead of sun-worshipping, consider self-tanning lotions and bronzers. You'll get that golden glow without the damage.

Published on July 15, 2009; updated on June 6, 2014.