Avoiding exposure to the sun is the best way to prevent skin cancer. But there's more you should know about early diagnosis of suspicious areas on the skin . . . .

Introduction

In an earlier article (link below) we described the main features of the three common types of skin cancer -- melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). Sunlight (the ultraviolet-B, or UV-B rays) plays an important role in the causation of all three types. One skin response to excess sun, actinic keratosis, is an indicator of trouble to come, so we shall discuss it briefly before going on to list the practical steps to avoid skin cancer.

Actinic keratosis

Actinic keratosis (sometimes called solar keratosis) documents the total exposure to solar radiation over the years. Thus the number and size of these lesions give some indication of the risk for the non-melanoma types of skin cancer - BCC and SCC.

Actinic keratosis lesions are irregular, ill-defined, pale-brown or flesh-colored patches; sometimes they are scaly, or quite dark in color. Less than one in 1,000 will convert into SCC within a year. Although this risk seems small, remember that there may be dozens of such foci on one person. Therefore, once they've been diagnosed, they should be removed.

The best way to remove actinic keratosis is using intense freezing (cryotherapy) with a single application of liquid nitrogen. This is a pretty painless procedure, and very effective. Occasionally, surgical removal is used for large lesions. Chemical destruction (with a drug called 5-fluorouracil) is an alternative if there are many lesions involving the head and neck; application is twice daily for 2 to 5 weeks, and there may be a risk of infection and inflammation. More cosmetic approaches include chemical peeling and facial dermabrasion.

Actinic keratosis lesions may pass unnoticed or be dismissed as 'age-spots'. If they start changing into a SCC, there may be pain, redness, ulceration, hardening, deeper color, and increasing size. Most SCCs occur at a site of previous actinic keratosis.

Actinic keratosis is also a forerunner of BCC, but it's now known that severe sunburns in childhood and adolescence may also be responsible for some cases of BCC. In the case of melanoma, episodes of childhood sunburn are more significant as the probable risk factor than the accumulated total 'dose' of sun exposure.

What's to be done?

It's known that 80% of lifetime sun exposure is acquired before age 18. This makes taking sensible precautions in childhood and adolescence the prime preventive measure.

Here are 4 "Safe Sun" guidelines that are sponsored by the American Academy of Family Physicians:

• Avoid exposure to sunlight when the sun is strongest, that is between 10 am and 4 pm.
• Apply a sunscreen or sunblock protection, even on cloudy days. The sun protection factor (SPF) must be 15 or greater. Put it on 30 minutes before you go into the sun, everywhere the sun might touch you (even ears and back of the neck). Men shouldn't forget any areas of baldness. Add more sunscreen if you are sweating a lot or swimming.
• Dress sensibly. Wear a wide-brimmed hat -- baseball caps won't do, as they allow exposure of the back of the neck and the tops of the ears. Sunglasses that block both UV-A and UV-B rays are important, and they can protect you from cataracts as well. Protective clothing (e.g. tightly woven fabrics and long-sleeved shirts) are necessary when exposure cannot be avoided.
• Don't try to get a suntan, and don't use tanning salons.

Early diagnosis improves the likelihood of a successful cure enormously. And the greatest delay in diagnosis has been shown to be due to late presentation of patients to their physicians, rather than misdiagnosis. So increased awareness of the possibility of skin lesions is paramount.

There is some disagreement among experts as to the right frequency for full-body examination by a physician. A good compromise is for everyone to examine themselves all over once a month, with an annual inspection by a physician after the age of 40. (Of course, if there are potential risk factors, such as a family history, examinations should start earlier and be more frequent). Annual examinations offer an opportunity for the dermatologist to remove any actinic keratosis lesions.

People with moles should know what to look for -- they can use the ABCDE rule:

• A symmetry -- when both sides of a mole don't look the same
• B order -- the edges are blurry or jagged
• C olor -- if the mole is darker than before, if the color spreads ordisappears, or multiple colors appear
• D iameter -- when a mole is larger than ¼ inch across
• E levation -- when a mole is raised above the skin and has a rough surface

Other changes that people should watch for:

• A mole that bleeds
• A mole that grows fast
• A scaly or crusted growth on the skin
• A mole that itches
• A place on your skin that feels rough, like sandpaper

Some other risk factors

There are some risk factors that cannot be influenced by lifestyle changes. Increasing age is a risk factor for BCC and SCC, but less so for melanoma, which is generally seen in early adulthood. A family history plays a role in the occurrence of melanoma, but not in BCC and SCC. Men are slightly more likely to get skin cancer -- of any type - than women.

Some chemicals can increase the risk for BCC and SCC: coal-tar products, tobacco, and psoriasis therapies (e.g. PUVA therapy). Radiation may increase the risk of melanoma. Finally, certain illnesses can increase the risk of BCC and SCC - chronic skin infections, human papillomavirus, and immunosupression for any cause.

Summary

Avoiding the sun's rays is the main way to prevent skin cancers. This fact needs repeating, again and again, to counteract the glamour of a suntan. Early recognition of actinic keratosis, and its prompt treatment, will prevent a number of cases of BCC and SCC.

Improved awareness of skin cancers will lead to regular full-body check-ups, and will also result in earlier reporting of potentially malignant skin changes. This is an area where good health education can really make a difference in saving lives and reducing disease.

You can see photos of various precancerous and cancerous lesions, online, in the Atlas of Dermatology -- see the link below.

Source

Overview of skin cancer detection and prevention for the primary care physician. AJ. Bruce, DG. Brodland, Mayo Clin Proc, 2000, vol. 75, pp. 491--500

Early detection and treatment of skin cancer. AF. Jerant, JT. Johnson, CD. Sheridan, TJ. Caffrey, Am Fam Physician, 2000, vol. 62, pp. 357--368

Links

• Recognizing Skin Cancer
• Online Atlas of Dermatology