Elizabeth A. Reid, MD Skin Cancer: Common and Usually Curable
men and women leave the world wrinkled, mottled, spotted, and scarred. In between birth and death, an individual’s skin re- places itself many hundreds of times and in the process accu- mulates enough DNA damage to make skin cancers the most com- mon of all cancers, with more than two million cases occurring in the United States each year. Fortunately, most skin cancers stay put in the locations where they start. They don’t invade nearby tissues and don’t spread through the base of the skin to travel to other parts of the body. For this reason, skin cancer is largely curable by simple removal of the cancerous lesions.
B Types of Skin Cancer
The three most common types of skin cancer arise from cells that grow in the epidermis, or outermost layer of the skin. The epidermis has at least three lay- ers. The inner layer of the epi- dermis is made up of basal cells. Basal cells regularly reproduce themselves in order to make squamous cells, which are re- placement skin cells that form a middle epidermal layer. This layer also contains cells called mel- anocytes. Melanocytes produce melanin, the pigment that gives skin its color. The outer layer of
10
ABIES arrive in the world with soft, smooth, usu- ally flawless skin. Old
Preventing and Controlling Skin Cancer
• Beginning early in life, protect your skin, particularly the skin on your face, scalp, ears, lips, back, arms, and hands. Use hats, shirts, and sunscreen (at least 30 SPF) to help block the harmful rays of the sun.
• Avoid prolonged sun exposure when the sun is high in the sky.
• At least once in middle age, have a professional examination of all your skin. If you are fair-skinned, and/or have sun damaged skin, heed your physician’s advice if he suggests more frequent checkups. The American Academy of Dermatol- ogy sponsors free screening exams every May.
• Make sure to keep an eye on your skin and have new, enlarging, color-changing, nonhealing, or bleeding spots checked by a physician.
the epidermis consists of dead skin cells that are constantly be- ing shed. The three most com- mon skin cancers come from these types of skin cells: basal cells, squamous cells, and mel- anocytes. Cancers arising from these cells are more common in fair-skinned, light-haired, light- eyed people. All three are also related to lifetime sun exposure. Basal cell cancer is the most common type of skin cancer, ac- counting for 80 to 90 percent of reported skin cancer cases. It is also the most benign form of skin cancer. Basal cell cancers begin with errors in a cell’s DNA. When abnormal cells are created by damaged DNA they form a tiny area of skin that is different from surrounding normal skin. Typi-
cally, this area looks like a little dome, with a waxy, pale appear- ance. Over time, tiny blood ves- sels may develop around it. It might bleed easily or develop a sunken center or a crusted top. Sometimes the color may be a little darker or rosier than that of the surrounding skin.
Basal cell cancers grow slowly and very rarely travel to other parts of the body. That said, they can invade nearby tissues, and the earlier they are removed, the less likely they are to recur (and the smaller the scar caused by their removal will be). Basal cell cancers occur most commonly on areas of the body exposed to the sun, especially the scalp, fore- head, and corner of the nose. They are also more common in
people who have been intermit- tently exposed to the sun without protection. Basal cell cancers take many years to develop, and by age sixty-five, about 50 per- cent of the population will have developed at least one such can- cer. Within five years of treat- ment of one basal cell cancer, one-half of patients will develop a second one. Because of the popularity of tanning, both indoors and out, basal cell cancers are now appearing in some people before middle age. Squamous cell cancers can occur in areas of the body that are not generally exposed to the sun, like the mouth and the geni- tal region. However, when squa- mous cell cancers appear on the skin, they typically develop in ar- eas that show other signs of sun damage—wrinkling,
freckling,
mottling, thinning, and sagging. They may also evolve from so- lar, or actinic, keratoses, which are
considered precancerous
markers of sun damage. Usually appearing as small red spots (un- der a quarter of an inch in diam- eter), solar keratoses have some white scaling on their surfaces. Some are sore and tender, and thickening with increased tender- ness can indicate a progression to a skin cancer. Squamous cell cancers can be flat and scaly patches of skin or firm, red nod- ules or nonhealing sores. Unlike (Continued on page 69)
A P R I L 2 0 1 2
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76