What Is Skin Cancer?

Skin cancer affects more people worldwide than all other types of cancer combined. Learn about skin cancer symptoms, treatments, and risk factors, as well as how to prevent it from striking you.

Skin cancer: An overview

Skin cancer is the most common type of cancer in the United States, with more cases diagnosed annually than every other type of cancer combined. It's so common that an estimated one in five Americans will develop one of the types of skin cancer—such as melanoma, actinic keratosis, basal cell carcinoma, or squamous cell carcinoma—by age 70. People of all ages can get skin cancer, but it's most common in people older than 50, those who have light-colored skin, who have a family history of skin cancer, or have spent lots of time out in the sun. Though a funny-looking mole is the skin cancer symptom people are most familiar with, it can present with many other symptoms as well. The good news: most skin cancers can be cured if they're caught early.

What causes skin cancer?
You probably already know this one: spending a lot of time out in the sun increases your risk for skin cancer. Why? The sun's ultraviolet (UV) rays damage the DNA in your skin cells, and sometimes, that damaged DNA goes haywire and produces mutations, or errors. The mutations can cause your skin cells to grow uncontrollably, forming tumors.
You're at an increased risk for skin cancer if you've been exposed to a lot of sun over a long period of time. But the scary truth is, you're also at risk if you've had just one blistering, peeling sunburn in your lifetime—even if you've spent the bulk of your adulthood slathering on sunscreen and staying in the shade.
Other skin cancer risk factors include:
Having red hair and fair skin
Having lots of moles on your body
Living at a high altitude
Exposure to radiation
A family history of skin cancer