All cancer originates from uncontrolled and abnormal growth of cells. Cells are the small individual units that together make up the different organs of our body. Cell growth is normally very tightly regulated and controlled by the body.
Skin cancer is the result of uncontrolled and abnormal growth of cells that originate in the skin. A tumor results when the unregulated cells continue to grow and increase in number. Different types of skin cancer develop from the different types of normal cells that reside in the skin.
Skin cancers are removed to prevent the tumor from further invading and destroying the normal structures that surround it and from spreading to other parts of the body (this is called metastasis). Metastasis is very rare except in melanoma and a few other unusual forms of skin cancer that are not common.
Types of Skin Cancer
Basal Cell Carcinoma
Basal cell carcinoma (BCC) is the most common type of skin cancer and accounts for 79% of all skin cancer. BCC originates from the bottom layer of cells in the epidermis (surface layer of skin) called the basal layer. BCC is the least dangerous type of cancer since it is slow growing and rarely spreads to other parts of the body except under extreme circumstances. It can, however, invade and destroy the local area and cause deformity if left untreated. This type of cancer is most common on the sun exposed areas of the head, neck, arms, and legs.
BCC usually appears as a sore that won’t heal or a pearly, shiny bump or knot that sometimes has small blood vessels within the affected area. The area may bleed with minor trauma. This tumor can be mistaken for pimples, cysts, scars, and rashes.
Squamous Cell Carcinoma
Squamous cell skin cancer (SCC) is the second most common type of skin cancer (15% of all skin cancer). It also arises from the outer layer of the skin from cells in the epidermis called squamous cells. SCC can occur anywhere on the skin, but is most common on the face and arms. It has many appearances, but most commonly is a rough and scaling bump or patch.
Unlike BCC, squamous cell carcinoma can spread into the lymph nodes and blood stream and become life threatening. This is more common in large and aggressive squamous cell carcinomas, cancers located on the ears, lips, or genitalia, or recurrent skin cancers that have been treated before. The overall chance of any squamous cell carcinoma spreading outside the local region is about 2%.
Squamous cell carcinoma in situ (also known as Bowen’s disease) is a superficial form of SCC that is limited to the epidermis or the outer layer of skin. Although SCC in situ does not grow deep into the skin, it can be very extensive in its diameter or width.
Melanoma is a form of skin cancer that develops from the pigment-making cells of the skin that give it color called melanocytes. These skin cancers are usually black or brown as a result. Melanoma accounts for 1–2% of all skin cancer. There are two common forms of melanoma that we see. Melanoma in situ (also known as Lentigo Maligna) is a superficial and slow-growing form of melanoma. This type is usually a large very slow growing freckle or brown patch of skin on the sun exposed areas. Although it tends to not be very dangerous, it can evolve into a Malignant Melanoma.
Malignant melanoma (MM) is a very dangerous form of skin cancer that has a strong tendency to spread to other parts of the body, but has an excellent prognosis if caught early. MM can occur anywhere on the skin, but is most commonly located on the legs of women or the backs of men. It is usually a brown to black lesion which is not uniform in border, color, or surface. The “ABCDE’s of melanoma” help distinguish a MM from a regular mole. The acronym stands for Asymmetry (most healthy moles are uniform), Border (irregular), Color (irregular or change in), Diameter, and Evolving (changing).
Facts and Figures
Skin cancer is the most common of all types of cancer. Over one million skin cancers are diagnosed each year in the United States alone. This is more than the combined number for all cancers of the prostate, breast, lung, colon, uterus, ovaries, and pancreas. The incidence of skin cancer has been on the rise for the past few decades.
Basal cell carcinoma is the most common and accounts for 79% of all skin cancers.
One in 59 men and women will be diagnosed with melanoma during their lifetime.
One in five Americans and one in three Caucasians will develop skin cancer in the course of a lifetime.
Skin cancer is the #1 cancer in men over age 50, ahead of prostate, lung, and colon cancer.
More than 20 people die each day from skin cancer, primarily melanoma.
Melanoma is the third most common cancer in women ages 20–39.
Squamous cell carcinoma is the second most common form of skin cancer (15% of all). More than 250,000 cases are diagnosed each year, resulting in approximately 2,500 deaths each year.
The percentage of women under age 40 with basal cell carcinoma has tripled in the last thirty years, while their rate of squamous cell cancer has increased fourfold.
The survival rate for melanoma patients with early detection is about 99%. The survival rate falls to between 15% and 65% or higher, depending on how far the disease has spread.
Causes of Skin Cancer
Ultraviolet (UV) Light and Sunburns
The sun gives off invisible rays of radiation energy. Ultraviolet rays are the ones most responsible for damaging the skin and causing cancer. When the skin is injured from UV light, it defends itself by tanning, but tanning does not prevent skin cancer. It is only a sign that the skin has been damaged. Most people receive 80% of their sun exposure by age 18. The damage to the skin from UV light accumulates over the years, making skin cancer more likely in older individuals. Tanning beds are artificial sources of UV light.
- One blistering sunburn in childhood more than doubles a person’s chances of developing melanoma later in life.
- More than 90% of all skin cancers are caused by sun exposure.
- A person’s risk for skin cancer doubles if he or she has had five or more sunburns.
- Ultraviolet radiation is a proven human carcinogen, according to the U.S. Department of Health and Human Services.
- Exposure to tanning beds before age 35 increases melanoma risk by 75%.
- People who use tanning beds are 2.5 times more likely to develop squamous cell carcinoma and 1.5 times more likely to develop basal cell carcinoma.
- Occasional use of tanning beds almost triples the chances of developing melanoma.
- New high-pressure sunlamps emit doses of ultraviolet radiation that can be as much as 15 times that of the sun.
Although sun exposure is the most important risk factor for skin cancer, there are other important risks to consider. People with a family history of skin cancer are at increased risk. Fair complexions with skin that easily burns or does not readily tan are also risk factors. Certain ethnic groups such as Scottish, Irish, and Northern Italians are particularly prone to skin cancer due to their fair skin. Melanoma occurs very strongly in certain families due to genetic factors. These people are at a much higher risk for melanoma.
Other causes for skin cancer include radiation, chronic arsenic exposure, certain wart viruses, and exposure to coal tar or pitch derivatives. If you have a history of any of these please notify our office at your appointment.