What are the key statistics about melanoma skin cancer?

What are the key statistics about melanoma skin cancer?  

Cancer of the skin is by far the most common of all cancers. Melanoma accounts for less than 2% of skin cancer cases but causes a large majority of skin cancer deaths.

Here are the American Cancer Society’s estimates for melanoma in the United States for 2015:

• About 73,870 new melanomas will be diagnosed (about 42,670 in men and 31,200 in women).

• About 9,940 people are expected to die of melanoma (about 6,640 men and 3,300 women).

The rates of melanoma have been rising for at least 30 years.

Melanoma is more than 20 times more common in whites than in African Americans. Overall, the lifetime risk of getting melanoma is about 2.4% (1 in 40) for whites, 0.1% (1 in 1,000) for blacks, and 0.5% (1 in 200) for Hispanics. The risk for each person can be affected by a number of different factors, which are described in the section “What are the risk factors for melanoma skin cancer?”
The risk of melanoma increases as people age. The average age at the time it is found is 62. But melanoma is not uncommon even among those younger than 30. In fact, it is one of the most common cancers in young adults (especially young women).

For melanoma survival statistics, see the section “What are the survival rates for melanoma skin cancer by stage?”

What is melanoma skin cancer?

What is melanoma skin cancer?

Melanoma is a cancer that starts in a certain type of skin cell. To understand melanoma, it helps to know about the normal structure and function of the skin.
Normal skin

The skin is the largest organ in your body. It does many different things, such as:

• Covering the internal organs and helping protect them from injury
• Serving as a barrier to germs such as bacteria
• Preventing the loss of too much water and other fluids
• Helping control body temperature
• Protecting the rest of the body from ultraviolet (UV) rays
• Helping the body make vitamin D
The skin has 3 layers: the epidermis, the dermis, and the subcutis (see picture).

Epidermis 

This top layer of skin is very thin, averaging only about 1/100 of an inch thick. It protects the deeper layers of skin and the organs of the body from the environment. 

The main types of cells in the epidermis include: 

• Squamous cells: These are flat cells in the outer part of the epidermis that are constantly shed as new ones form.  

• Basal cells: These cells are in the lower part of the epidermis, called the basal cell layer. These cells constantly divide to form new cells to replace the squamous cells that wear off the skin’s surface. As these cells move up in the epidermis, they get flatter, eventually becoming squamous cells.  

• Melanocytes: These are the cells that can become melanoma. They make a brown pigment called melanin, which gives the skin its tan or brown color. Melanin protects the deeper layers of the skin from some of the harmful effects of the sun. For most people, when skin is exposed to the sun, melanocytes make more of the pigment, causing the skin to tan or darken.   

The epidermis is separated from the deeper layers of skin by the basement membrane. When a skin cancer becomes more advanced, it generally grows through this barrier and into the deeper layers. 

Dermis 

This middle layer of the skin is much thicker than the epidermis. It contains hair follicles, sweat glands, blood vessels, and nerves that are held in place by a protein called collagen, which gives the skin its elasticity and strength. 

Subcutis 

The deepest layer of the skin (the subcutis) and the lowest part of the dermis form a network of collagen and fat cells. The subcutis helps the body conserve heat and has a shock-absorbing effect that helps protect the body’s organs from injury. 

Benign skin tumors 

Many types of benign (non-cancerous) tumors can develop from different types of skin cells.

Benign tumors that start in melanocytes  

A mole (nevus) is a benign skin tumor that develops from melanocytes. Almost everyone has some moles. Nearly all moles (nevi) are harmless, but having some types can raise your risk of melanoma. See the section “What are the risk factors for melanoma skin cancer?” for more information about moles. 

A Spitz nevus is a kind of mole that sometimes looks like melanoma. It is more common in children and teens, but it can also be seen in adults. These tumors are generally benign and don’t spread. But sometimes doctors have trouble telling Spitz nevi from true melanomas, even when looking at them under a microscope. Therefore, they are often removed, just to be safe. 

Benign tumors that develop from other types of skin cells   

• Seborrheic keratoses: Tan, brown, or black raised spots with a “waxy” texture 

• Hemangiomas: Benign blood vessel growths, often called strawberry spots 

• Lipomas: Soft growths made up of fat cells 

• Warts: Rough-surfaced growths caused by some types of human papilloma virus (HPV) 

Most of these tumors rarely, if ever, turn into cancers. There are many other kinds of benign skin tumors, but most are not very common.