The essential facts about skin cancer

To the untrained eye, skin cancer can look a lot like a harmless pimple or mole — so it’s easy to overlook or ignore it. But it’s important to keep a close eye on your skin, because skin cancer can happen to anyone at any age. In fact, 1 in 5 Americans gets some form of skin cancer by the age of 70.^{1, 2}  

But if you detect skin cancer early, you’ll likely have a better outcome, explains Thomas Rohrer, M.D., director of dermatologic surgery at SkinCare Physicians in Chestnut Hill, Massachusetts.  

Find out who’s at a higher risk of skin cancer, what the symptoms can look like and how to help prevent it.

Too much exposure to ultraviolet (UV) rays from the sun is the top cause of skin cancer, though UV light from tanning beds is equally damaging. Skin cancers start at the upper layer of the skin.

Here’s what happens: Healthy skin cells are constantly copying and replacing themselves. But excess UV can damage the DNA in skin cells and cause abnormal changes. The abnormal cells may multiply at a much higher rate, explains Dr. Rohrer. Eventually those damaged cells may form tumors, which can be cancerous.³

There are four main types of skin cancer:⁴

Is the most common. It usually appears on the parts of the body that get the most sun, including your face, scalp, ears, neck or arms, explains Dr. Rohrer. Basal cell cancer is slow growing. It’s important to have it removed early though. “If it continues to grow, it can eat away at its location, causing a lot of destruction,” Dr. Rohrer says.

What it looks like: A round-like patch. “But instead of going away, it slowly gets bigger,” Dr. Rohrer explains.

Is the second most common. It also tends to start on the parts of the body that get the most sun. Squamous cell cancer can go deep into the skin and spread to other parts of the body.

What it looks like: A red bump, scaly patch or a sore that won’t heal.

Affects the cells that give skin its tan or brown color. Melanoma can grow anywhere on your body — not just the skin exposed to the sun, notes Dr. Rohrer. It can quickly spread through the blood or lymphatic system to other parts of the body too. That makes it the most serious kind of skin cancer.

What it looks like: It often starts inside a mole or dark spot. It also has what’s known as ABCDE features:⁵

• Asymmetry, meaning one half of the spot doesn’t look the other half
• Border or edge that is irregular or not well-defined
• Color that changes from one part of the spot to the other
  
• Diameter or size is usually as large as a pencil eraser
• Evolving (or changing) in size, shape or color over time, or the spot looks different than the rest

Is rare. But it can spread quickly too. It usually develops in people over age 50 who have fair skin.⁶

What it looks like: An insect bite, sore or pimple.⁶ 

Other risk factors for skin cancer include:²

• Having 5 or more bad sunburns that cause blisters between the ages of 15 and 20
• Having more than 50 moles, atypical moles or large moles increases your risk of developing melanoma
• A lot of unprotected exposure to ultraviolet (UV) rays, from going to tanning salons or sun exposure frequently
  
• A personal and/or family history of melanoma  

“It depends on the type, size and location of your skin cancer,” says Dr. Rohrer. But it can involve the following:

“For small cancers that haven’t spread, your doctor might suggest a cream that you put on your skin,” says Dr. Rohrer. Some creams have chemotherapy agents that kill the cancer cells. 

A surgeon scrapes or cuts out the cancer after numbing the skin with anesthesia.⁸

A surgeon uses a microscope to carefully inspect and remove small amounts of skin until the cancer is all gone.⁸ “Especially when the cancer is on the face, this technique spares tissue. We don’t take any more tissue than we absolutely have to,” says Dr. Rohrer.  

Chemo drugs may be used to stop the growth of cancer cells.⁸

When you’re outside, wear sun protection factor (SPF) clothing that covers your arms and legs. And wear a wide-brimmed hat and UV blocking sunglasses.⁹

Use sunscreen too. Get a broad-spectrum, water-resistant one with an SPF of 30 or higher. Then reapply every 2 hours, or right after swimming or sweating a lot⁹

Make sure to apply it to the spots people often miss, explains Dr. Rohrer, including the insides and backs of the ears, tops of the feet, hands, lips and any bald spots on your head or where your hair parts.

Protecting yourself from the sun whenever you’re outside may help lower your risk. And the earlier you catch skin cancer, the better. That’s why skin checks with a dermatologist are critical.