Skin Cancer

Basic Facts

What is Skin Cancer?

Skin cancer refers to cancer that develops in one of the tissues of the skin. It  becomes more common as the effects of years of sun exposure begin to show. Some types of skin cancer are, at most, a minor problem. Other skin cancers are life-threatening conditions. Getting a regular annual check-up by a healthcare professional, and being alert to any skin changes, are the best ways to keep your skin healthy.  

What is Not Skin Cancer?

There is a common type of skin lesions in older adults which is not a skin cancer. It is called seborrheic keratosis. These lesions starts to appear when people enter their 50s, and gradually increase in number. The lesions look like superficial, stuck-on, dark brown growths, and are usually found on the torso and face. 

How Common is Skin Cancer?

The rate of skin cancer has risen in the United States over the last several decades, most likely because of the thinning ozone layer, as well as the popularity of sun-bathing and tropical vacations. Annually, more than 2 million cases of all types of skin cancer are identified in this country. Nine out of 10 skin cancers belong to the basal cell type (described in greater detail below).

Some people are diagnosed with skin cancer more than once in their lives. About half of all Americans will be diagnosed with some form of skin cancer before they reach age 65.

The Most Common Types of Skin Cancer 

The three most common types of skin cancer are:

  • Basal cell carcinoma
  • Squamous cell carcinoma
  • Melanoma

Basal Cell Carcinoma

Basal cell carcinoma is the most common skin cancer of any type in the United States.  It is rarely fatal. It is a type of cancer that starts in the outer layer of the skin (epidermis). In most cases, it grows slowly in its original location, and does not spread (metastasize) to other parts of your body. It must be treated because it can eventually destroy underlying tissues and bone if it is not removed. Three subtypes of basal cell carcinoma that are often seen include nodular, superficial, and pigmented (which can be confused with melanoma).  

Squamous Cell Cancer

Squamous cell cancer is the second most common skin cancer. It develops from the flat squamous cells on the surface of the skin and is most likely to show up in skin areas that have been regularly exposed to the sun for long periods of time. It may also develop in wounds that take an abnormally long time to heal, and in scars caused by burns or radiation. This type of skin cancer is more invasive and destructive than basal cell skin cancer. Its tendency to spread to other parts of the body is low, but the risk of spread is higher than with the basal cell type.   


Melanoma is the most dangerous form of skin cancer, with the greatest risk of spreading to other parts of the body. Melanomas begin in melanocytes, the specialized cells in your skin that produce melanin (a skin pigment). A melanoma is likely to spread to other areas of the skin, as well as to the brain, lungs, and intestines. This type of cancer is difficult to treat in later stages. If caught early, however, 97% of melanomas can be cured. 

There are four types of melanoma:

  • Lentigo maligna
  • Superficial spreading
  • Nodular
  • Acral lentiginous

Last Updated August 2020