Skin Cancer, Danger And Protection

YOUR SKIN

“People are unaware of the very real risk posed by the sun . . . and the damage it can cause to the skin’s DNA. Accumulation of this damage can lead to a skin cancer time bomb.”​—Dr. Mark Birch-Machin, skin-cancer expert.

THE skin is the body’s largest organ, measuring some 20 square feet [1.8 sq m] for an average male and 17 square feet [1.6 sq m] for an average female. It contains receptors that respond to pain, touch, and temperature. The skin is the body’s first line of defense against heat, cold, and trauma, as well as against toxins, chemicals, and pollutants. It makes the body waterproof and leakproof. However, the skin has a potential enemy​—the sun. But is not sunlight essential to life?

Yes, it is. Plants, upon which we depend, need sunlight for growth. Moreover, small amounts of sunlight stimulate the body to produce vitamin D, which metabolizes calcium, building strong bones. But this does not mean that if a little is good, more is better. The sun produces ultraviolet (UV) radiation, which can cause irreversible damage to the skin. One result is premature aging.

The book Saving Your Skin warns of an even greater danger: “Ultraviolet light damages DNA [the genetic material that controls cell activities, such as cell division], causes immunosuppression and may activate chemicals in the body that stimulate the chain of events leading to cancer.” The word “cancer” is frightening. But just how prevalent is skin cancer? Is there cause for alarm?

Skin Cancer​—A Modern-Day Plague

The Merck Manual states that this is the most common type of cancer in the world. In the United States, 1 out of every 6 to 7 people gets some form of skin cancer. But rates are increasing. According to Dr. I. William Lane in the book The Skin Cancer Answer, “it is now estimated that 50 percent of people who reach the age of sixty-five will develop some form of skin cancer.” Malignant melanoma causes some 7,500 deaths yearly in that country and is on the rise, according to the American Academy of Dermatology. Dark-skinned people have a lower incidence of skin cancer, but they too are at risk.

Why has skin cancer become such a plague? While there may be many relevant  factors, such as elevation, latitude, the amount of cloud cover, and the condition of the ozone layer, the main culprit may simply be too much exposure to the sun. Life-styles have changed. Vacations at the beach and outdoor recreation such as mountain climbing and skiing have become more popular and accessible for people with indoor occupations. Fashions have changed. Whereas modesty used to dictate that men and women wear long swimming costumes, swimming suits have become ever skimpier, exposing more of the skin. Skin cancer has increased correspondingly. Did desert dwellers such as the Bedouin, with their long, flowing robes and head coverings, know something that we seem to have ignored?

Skin Cancer​—A Very Real Danger

The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. Basal cell and squamous cell carcinomas begin in the outer layer of the skin, which is only 1/25th of an inch thick [1 mm] on the average. These nonmelanoma cancers appear to result from chronic sun exposure, such as that of outdoor workers, and they occur almost exclusively on parts of the body exposed to the sun, such as the face and the hands. * These carcinomas tend to begin as a nodule or a lesion on the skin that enlarges, often bleeds, and does not heal completely. It may spread locally, invading surrounding tissue. About 75 percent of skin cancers are basal cell carcinomas. Although less common, squamous cell carcinoma is more likely to metastasize, or spread, from the primary site to other parts of the body. Early diagnosis is important because while nonmelanomas are the most curable type of skin cancers, they can result in death if left untreated.

Malignant melanomas, which account for only 5 percent of all skin cancers, also begin in the outer layer of the skin. One of the main factors for developing melanoma appears to be intense, intermittent exposure to the sun, such as that received by indoor workers who vacation in the sun. Some 50 percent of malignant melanomas develop from pigmented moles, particularly on the upper back and lower legs.

This type of skin cancer is the most deadly, for if it is not treated early, it can invade the inner layer of the skin, the dermis, where blood vessels and the lymph are located. From there it can quickly metastasize. Says oncologist Dr. Larry Nathanson: “The paradox of melanoma is that it is a highly curable disease when it is treated early. On the other hand, when it is metastatic it is relatively resistant to treatment by drugs or radiation.” In fact, only 2 or 3 percent of patients with metastasized melanoma survive for five years. (See the box on page 7 for early warning signs of melanoma.)

Who are at risk for skin cancer? In addition to people who have had chronic or intense, intermittent exposure to the sun, those with fair skin, light hair and eyes, moles and freckles, and a family history of the disease are especially at risk. Skin cancer is much less likely among people with a darker complexion. Does this mean that the more tanned you are, the less danger there is of skin cancer? No, because although tanning is the skin’s reaction to protect itself from UV radiation, the skin is damaged during the tanning process, and repeated injury increases your risk of skin cancer.

Treatment of Skin Cancer

Depending on the type of tumor, its location and size, and previous therapy, there are several methods of treatment: surgical excision, scraping, burning with an electric needle, cryosurgery (freezing), and radiotherapy. The challenge is to remove all cancerous cells. A procedure called Mohs surgery, using microscopically controlled excision, is effective in eradicating basal cell and squamous cell carcinomas (a 95 to 99 percent cure rate), while preserving the greatest amount of healthy tissue and producing less noticeable scarring. In any case, tissue reconstruction may be necessary.

The U.S. National Institute on Aging says: “All skin cancers could be cured if they were discovered and brought to a doctor’s attention before they had a chance to spread.” Thus, early detection is vital. But what can be done to prevent skin cancer?

Educate Yourself About Safe Sun Habits

Education about safe sun habits is necessary from childhood. According to The Skin Cancer Foundation, most ‘people receive about 80 percent of their lifetime sun exposure before the age of 18. Just one blistering sunburn in childhood is estimated to double the risk of melanoma later in life.’ This is because skin cancer can take 20 or more years to develop. (See the box on page 8 for useful tips on safe sun habits.)

Australia has a high rate of skin cancer​—in particular, of melanoma. * This is because the country is populated mainly by fair-skinned Northern European immigrants, the majority of whom live along the coast with its sunny beaches. A study of these immigrants suggested that the earlier in their life they arrived in Australia, the greater their risk of melanoma, bearing out the need to educate about safe sun habits from an early age. The Australian government has mounted an aggressive campaign to educate people about the dangers of the sun, using the slogan “Slip, Slap and Slop,” which stands for “Slip on a T-shirt, Slap on a hat, and Slop on sunscreen.” These moderate changes in life-style are having an impact on the incidence of melanoma among younger age groups in that country.

As to sunscreen, using a broad-spectrum product that filters out both UVA and UVB radiation is wise. This is important even on cloudy days because 85 percent of UV rays can penetrate clouds. The rays can also penetrate clear water. A sunscreen with a sun protection factor (SPF) of at least 15 is recommended by some experts. To find out how much protection this affords, multiply the number of minutes in which you normally burn by 15. Sunscreen should be reapplied at least every two hours, but this does not double the total protection time.

 Moreover, The Skin Cancer Answer warns that you should not be lulled into a false sense of security just because you use sunscreen. No sunscreen is 100 percent effective against sunburn, nor does it necessarily prevent skin cancer. In fact, the use of sunscreen may indirectly increase the risk of skin cancer​—if using it causes you to stay in the sun longer. The book notes: “There is no substitute for safe sun habits. Wearing protective clothing and staying indoors during peak sunlight hours are considered ‘effective’ weapons against skin cancer.”

What about getting a tan indoors, from sun lamps and tanning beds? Just 20 minutes in a tanning salon is estimated to be equivalent to approximately four hours in the sun. Indoor tanning was thought to be safe because it used mainly UVA radiation, which did not seem to cause burns. But The Skin Cancer Answer states: “It is now known that UV-A penetrates more deeply into the skin than UV-B, can cause skin cancer, and may suppress the immune system.” One study reported on in the international edition of The Miami Herald found that women who visited tanning salons once a month or more “increased their chance of developing melanoma by 55 percent.”

Thus, it is necessary to give serious attention to safe sun habits. Remember, the sunburn you receive today may develop into skin cancer 20 years or more in the future. How have some struggled with skin cancer, and what has helped them to cope?

early melanomas are often uneven and may have scalloped or notched edges. Common moles have smoother, more even borders.

KEY WARNING SIGNS OF MALIGNANT MELANOMA

1. ASYMMETRY. Most early melanomas are asymmetrical (the two sides do not match). Common moles are round and symmetrical.

2. BORDER IRREGULARITY. The borders of early melanomas are often uneven and may have scalloped or notched edges. Common moles have smoother, more even borders.

3. COLOR VARIABILITY. Varied shades of brown, tan, or black are often the first sign of melanoma. As melanomas progress, the colors red, white, and blue may appear. Common moles usually are a single shade of brown.

4. DIAMETER. Larger than common moles, early melanomas tend to grow to a diameter of more than one fourth of an inch [6 mm].

TIPS FOR SAVING YOUR SKIN

1. Limit sun exposure, especially between 10:00 a.m. and 4:00 p.m., the peak hours for harmful ultraviolet (UV) radiation.

2. Examine your skin from head to toe at least once every three months.

3. When outdoors, use a broad-spectrum sunscreen rated SPF 15 or higher. Apply it liberally 30 minutes before sun exposure and every two hours thereafter. (Sunscreen should not be used on children under six months of age.)

4. Teach your children good sun protection habits at an early age, for the damage that leads to adult skin cancers starts in childhood.

5. Wear protective clothing such as long pants, long-sleeved shirts, broad-brimmed hats, and UV-protective sunglasses.