Q: What steps can I take to avoid skin cancer?

A: Skin cancer is by far the most common type of cancer in the United States, according to the American Cancer Society. It affects people of all skin tones, despite complexion and skin pigmentation. The most preventable cause of skin cancer is overexposure to ultraviolet light, either from the sun or from artificial sources, such as tanning beds.

There are three main types of skin cancer. Basal cell carcinoma and squamous cell carcinoma are cancers most often found in areas exposed to the sun, such as the head, neck and arms. These cancers are very common and usually very treatable. Melanoma is less common, but is the most concerning skin cancer due to its risk of spreading elsewhere in the body.  When discovered early, melanoma can be cured. But despite amazing advances in treatment, advanced melanoma can still be deadly.

The ACS estimates there will be about 91,270 new cases and 9,320 deaths from melanoma in 2018. Although melanoma accounts for only 1 percent of skin cancers, it causes the most skin cancer deaths.

The ABCDE rule of skin sancer

A new spot on the skin, or a spot that's changing in size, shape, or color is the most important warning sign for skin cancer. The ABCDE rule is a useful guide in helping patients and medical providers to identify high-risk lesions or potential malignancies.

  • Asymmetry: Melanoma lesions are often asymmetrical (not equal on both sides) in shape. Benign moles are usually symmetrical.
  • Border: Melanoma lesions usually have irregular borders that are hard to define. Non-cancerous moles usually have smooth borders.
  • Color: A mole with more than one color (blue, black, brown, tan, etc.) or the uneven distribution of color may be a warning sign of melanoma. Benign moles are usually a single shade of brown or tan.
  • Diameter: Melanoma lesions are often larger than 6 millimeters in diameter (about the size of a pencil eraser).
  • Evolution: If a mole or skin lesion that someone has had for years begins to undergo changes in color and/or size, contact your provider as soon as possible.

Although those who get a lot of exposure to ultraviolet light are at higher risk for skin cancer, it isn't necessary to avoid the sun completely. Here are a few tips to prevent skin cancer:

  • Seek shade when the sun is strongest, between 10 a.m. and 4 p.m. Use the shadow test to determine how strong the sun's rays are: If your shadow is shorter than you, then rays are strongest.
  • Protect with clothing. If light can shine through your clothing, then UV rays can penetrate, as well. Dark colors provide better protection than light ones, as do more tightly knit weaves. Wear UV-blocking sunglasses for eye protection and a wide-brimmed hat to protect your scalp, face and ears. There is now SPF clothing that can provide built-in UV protection.
  • Use a broad spectrum (UVA/UVB) sunscreen with an SPF of 30 or higher on unprotected skin. Pay close attention to the face, ears and neck. Use lip balm with sunscreen on your lips. Be aware that sunscreen does not block all UV rays and needs to be reapplied at least every two hours to maintain protection, especially when sweating or swimming. Sunscreen is just as important on hazy or overcast days.
  • Avoid tanning beds, booths and sunlamps. There is no safe tanning. Studies have shown that exposure to UV radiation damages your skin, whether the exposure comes from tanning beds or natural sunlight.

Jeffrey Farma, MD, FACS is the codirector of the melanoma and skin cancer program at Fox Chase Cancer Center.