Understanding Skin Cancer

What Is Skin Cancer?

skin cancers involve abnormal cell changes in the outer layer of skin called the epidermis.It is by far the most common cancer in the world. Most cases are cured, but the disease is a major health concern because it affects so many people. The incidence of skin cancer is rising, even though most cases could be prevented by limiting the skin's exposure to ultraviolet radiation.Skin cancer is about three times more common in men than in women, and the risk increases with age. Most people diagnosed with skin cancer are between ages 40 and 60, although all forms of the disease are appearing more often in younger people. If you or any close relatives have had skin cancer, you are more likely to get the disease.Every malignant skin tumor in time becomes visible on the skin's surface, making skin cancer the only type of cancer that is almost always detectable in its early, curable stages. Prompt detection and treatment of skin cancer is equivalent to cure.Types of Skin CancerSkin cancers fall into two major categories: melanoma and non-melanoma.Melanoma can start in heavily pigmented tissue, such as a mole or birthmark, as well as in normally pigmented skin. Melanoma usually appears first on the torso or back, although it can arise on the palm of the hand; on the sole of the foot; under a fingernail or toenail; in the mucous linings of the mouth, vagina, or anus; and even in the eye.Melanoma is an extremely virulent, life-threatening cancer. It is readily detectable and usually curable if treated early, but it progresses faster than other types of skin cancer and tends to spread beyond the skin to affect the bones or brain. Once this occurs, melanoma becomes very difficult to treat and cure.The two most common skin cancers, basal cell carcinoma and squamous cell carcinoma, are non-melanomas, which are rarely life-threatening. They progress slowly, seldom spread beyond the skin, are detected easily, and usually are curable. Basal cell carcinoma, which accounts for nearly 3 out of 4 skin cancers, is the slowest growing. Squamous cell carcinoma is somewhat more aggressive and more inclined to spread. In addition, there are a few rare non-melanomas, such as Kaposi's sarcoma, a potentially life-threatening disease characterized by purple growths and associated with a suppressed immune system and almost always seen in patients with AIDS.Some technically noncancerous skin growths have the potential to become cancerous. The most common are actinic keratoses - crusty reddish lesions that may scratch off but grow back on sun-exposed skin. Another precancerous skin growth, cutaneous horns, appears as funnel-shaped growths that extend from a red base on the skin.

Who Is at Highest Risk?

Skin cancer tends to strike people of light skin color. Dark-skinned people are rarely affected, and then only on light areas of the body such as the soles of the feet or under fingernails or toenails. An estimated 40% to 50% of fair-skinned people who live to be 65 will develop at least one skin cancer. The incidence of skin cancer is predictably higher in places with intense sunshine, such as Arizona and Hawaii. It is most common in Australia, which was settled largely by fair-skinned people of Irish and English descent.

What Causes It?

Excessive exposure to sunlight is the main cause of skin cancer. Sunlight contains ultraviolet (UV) rays that can alter the genetic material in skin cells, causing mutations. Sunlamps, tanning booths, and X-rays also generate UV rays that can damage skin and cause malignant cell mutations. Basal cell carcinoma and squamous cell carcinoma have been linked to chronic sun exposure, typically in fair-skinned people who work outside. Melanoma is associated with infrequent but excessive sunbathing that causes scorching sunburn. One blistering sunburn during childhood appears to double a person's risk for developing melanoma later in life.
Fair-skinned people are most susceptible because they are born with the least amount of protective melanin. Redheads, blue-eyed blonds, and people with pigment disorders such as albinism are at the greatest risk. But people with many freckles or moles, particularly abnormal-looking ones, may also be vulnerable to melanoma. Workers regularly exposed to coal tar, radium, inorganic arsenic compounds in insecticides, and certain other carcinogens are at slightly higher than normal risk for non-melanoma skin cancer.