Skin cancer is the most common malignancy diagnosed in the United States with over 1,250,000 new cases reported each year. Americans over the age of 65 have a forty to fifty percent chance of developing at least one skin malignancy. Your Skin: Layer by Layer
Although we don’t tend to think of it as such, the skin is the largest organ in the human body, weighing approximately six pounds. The outermost layer is called the epidermis, which is further divided into different layers:
Stratum Corneum: consists of flattened keratinocyte cell remnants (mostly keratin). This is the surface layer of the skin and is constantly being shed.
Stratum Granulosum & Stratum Spinosum: consist of keratinocytes (squamous cells) at different stages of maturation.
Stratum Basale: consists of cuboidal shaped keratinocytes (basal cells). The melanocytes (pigment-producing cells) are also found in this layer.Beneath the epidermal levels is the dermis. The dermis contains blood vessels, sweat glands hair follicles and lymph vessels. The dermis also contains glands that produce sebum, an oil that prevents the skin from drying out.
Types of Skin Cancer
Three different types of cancer affect the epidermis: basal cell carcinoma, squamous cell carcinoma and malignant melanoma.
Basal cell carcinoma (BCC) is the most common type of epidermal cancer. Over one million Americans are diagnosed with BCC every year. Basal cell carcinoma is slow growing, and rarely metastasizes (the medical term for cancer that spreads to other organs).
Squamous cell carcinoma (SCC) is less common than BCC, accounting for 200,000 news cases a year in the U.S. Although squamous cell carcinoma spreads faster than BCC, it is still uncommon for the disease to metastasis.
Malignant melanoma is the rarest of the types of skin cancer, with approximately 50,000 new cases in the U.S annually. However, malignant melanoma is also the fastest growing of the three cancers, and diagnosis rates of the disease have doubled in America since the 1970s. Malignant melanoma begins in the melanocytes, and is more often called just melanoma.
Common Causes: Tanning and DNA Damage
Ultraviolet rays from sunlight are the most common cause of skin cancer. The UV rays damage DNA in the epidermis. The damaged DNA replicates and allows the cellular damage to spread. Light-skinned and fair-haired people are most susceptible to UV-related DNA damage.
Tanning and exposure to the sun without sunscreen or protective clothing adds to the risk of skin cancer development. The UV rays used in tanning salons are just as damaging to DNA as UV found in sunlight.
ABCDE Rule for Skin Cancer
Periodic self-examinations for new or abnormal-looking moles, growths, sores, and skin discoloration can help catch skin cancer in its earliest stages. (A mirror or a partner can help you check hard-to-see places.) Use the ABCDE rule for skin cancer: Asymmetry, Border, Color, Diameter, and Elevation:
Asymmetry: One side of the growth or mole differs in shape from the other side.
Border: The border of the abnormal area changes from smooth to blurry, irregular or “ragged.” Pigment from the area may “bleed” into the
Color: The mole has multiple colors and shades. These colors may be tans and browns, but may also be white, red, pink or even blue. Watch for color changes.
Diameter: Has the mole or growth increased in size since you last examined it? Increases in size are most common, but shrinkage may also occur. Report any mole larger than 1/4 of an inch (about the width of a pencil eraser) to your doctor.
Elevation: Has a previously flat mole become raised, or elevated from the surrounding skin? A change of thickness should be discussed with your physician.
The ABCDE rule for skin cancer applies mainly to melanoma and helps you remember features to check for possible malignancy. Other signs to look for include open sores, raised bumps, red patches, pink-colored growths and scar-like formations. Report any discomfort, such as burning or itching, or bleeding from a skin lesion to your doctor for further examination.
Survival Rates and Mortality
If an epidermal skin cancer is diagnosed and treated in its early stages, survival rates are very good. Almost 100 percent of non-melanoma skin cancers can be cured with early treatment. Five year survival rates for early stage malignant melanoma are approximately ninety percent. Once melanoma metastasis, five-year survival rates drop to fifty percent.