Skin cancer forms in the tissues of the skin. There are several types of skin cancer. Skin cancer that forms in melanocytes (skin cells that make pigment) is called melanoma and is the most aggressive type. Skin cancer that forms in the lower part of the epidermis (the outer layer of the skin) is called basal cell carcinoma. Skin cancer that forms in squamous cells (flat cells that form the surface of the skin) is called squamous cell carcinoma. Most skin cancers form in older people on parts of the body exposed to the sun or in people who have weakened immune systems.
For all types of skin cancer the main risk is over-exposure to ultraviolet light from sunlight or tanning beds. Over-exposure in childhood puts people at much greater risk of developing melanomas later in life. There are several other things that increase the risk of skin cancer:
Exposure to radiation or long-term exposure to chemicals, such as coal tar, soot, pitch, asphalt, creosote, paraffin wax or arsenic, can also increase the risk of developing non-melanoma skin cancer.
Skin cancers are the most common of all cancer types and basal cell carcinoma is the most common skin cancer. Anyone can develop skin cancer — even people with darker skin, hair and eyes. However, skin cancer is more common in people who have light-colored skin, hair and eyes. It’s also more common in those who spend time in the sun without protective clothing, have been sunburned, are over the age of 40 and have a family history of skin cancer. One in five Americans will develop skin cancer in the course of their lifetime.
The majority of melanomas occur on the head, neck, arms and back — the skin most-often exposed to sunlight. Melanoma is usually dark or black, but can be lighter brown or even speckled. The surface is usually raised and sometimes rough. In the early stages, it can look like a mole, but with a ragged outline and different shades of color. Sometimes, it may appear as a mole that is bleeding, oozing or crusty. The most important thing is that melanoma usually changes shape or color as it grows. Any spot that changes shape or color should be reported to your healthcare provider. Visit the melanoma section to learn more.
The majority of basal cell carcinoma (BCC) occurs on the face. It starts as a small, pink, pearly or waxy spot, that is often circular or oval in shape. As it grows, it can become a raised, flat spot with a “rolled” edge and may develop a crust. Then, it can bleed at the center and develop an ulcer. This is called a rodent ulcer and, if left untreated, can become large and erode the skin and tissue below. Basal cell carcinoma is a non-melanoma skin cancer. Visit the basal cell carcinoma section to learn more.
Squamous cell carcinoma (SCC) is most common on the limbs, head and neck. It is pink and irregular in shape, usually with a hard, scaly or horny surface, and it can become ulcerated. The edges are often raised and it may be tender to the touch. Squamous cell carcinoma is a non-melanoma skin cancer. Visit the squamous cell carcinoma section to learn more.
Malignant melanoma can be one of the most dangerous types of cancer. It can spread into nearby tissue, if left untreated. Some types of melanoma grow faster and spread further than others. If diagnosed late, treatment may not be able to cure the cancer.
Squamous cell carcinoma can also spread, but more slowly than melanoma. Even the types of SCC that spread more rapidly can be effectively treated as long as they are diagnosed fairly early.
Basal cell carcinoma almost never spreads, apart from the slow growth of a rodent ulcer itself. Even in advanced cases, treatment for BCC is almost always successful.
There are some rare, inherited skin diseases, known generally as photodermatosis, which make people highly sensitive to sunlight and more likely to get skin cancer. Skin cancer is more common in light-colored, freckly skin. In addition, there is evidence that if you have a close relative (brother, sister parent or child) with skin cancer, you have about twice the normal risk of getting that type of skin cancer.
Ultraviolet (UV) light — from sunlight or tanning beds — is the main cause of skin cancer. It can damage the DNA make up in the genes of skin cells and cause the cells to become cancerous. There are two main types of UV light — UVA and UVB. UVB was originally found to cause sunburn and skin cancer, but more recently, it has been discovered that UVA can also cause skin cancer.
UVB light is known to cause sunburn and skin cancer, so most tanning beds were originally designed to produce only UVA light. However, recent research has found that UVA can also cause skin cancer. It is best to avoid tanning beds all together in order to lower your risk of developing skin cancer.
UVB light is known to cause sunburn and skin cancer, so most sunscreens were originally designed to block out only the UVB rays. But UVA light can also cause skin cancer and many sunscreens now block out UVA rays, as well as UVB. A big concern, however, is that since most sunscreens prevent sunburn, people will spend much more time in the sun. As a result, this over exposure to sunlight, and ultraviolet light, increases the risk of developing skin cancer.
For almost all non-melanoma skin cancers, such as basal cell carcinoma and squamous cell carcinoma, and for early melanomas, surgery to remove the cancer and a small amount of surrounding tissue may be all that is needed. If a melanoma has spread, chemotherapy can be used, but may not eliminate the cancer. Additional surgery and radiation therapy may be needed for any secondary tumors, as well.
Surgical treatment of non-melanoma skin cancer, such as basal cell carcinoma and squamous cell carcinoma, is usually completely effective. For melanoma, if the tumor is surgically removed before it has spread, the treatment is usually quite effective. By removing more tissue around the tumor (the margin), its spread is more likely to be halted and the chance of a cure is increased. Once a melanoma has spread to other parts of the body, treatment is usually aimed at prolonging life, as the chance of a cure is limited.
Early diagnosis is critical for malignant melanoma, as treatments for advanced melanoma are rarely effective. For other types of skin cancer, early diagnosis is recommended as well, so treatment can begin as soon as possible.
Skin cancer can be prevented, by following these easy and sensible steps: