The most heartening news about melanoma is that many cases of skin cancer can be prevented simply by following these precautions:

• Avoid the sun between 10 a.m. and 3 p.m. Because the sun's rays are strongest during this period, try to schedule outdoor activities for other times of the day, even in winter or when the sky is cloudy. You absorb UV radiation year-round, and clouds offer little protection from damaging rays.

• Wear sunscreen summer and winter. Sunscreens don't filter out all harmful UV radiation, especially the radiation that can lead to melanoma. But they play a major role in an overall sun protection program. Be sure to use a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 15 when you go outside, summer and winter. Broad-spectrum products provide protection against both UVA and UVB radiation. Use sunscreen on all exposed skin, including your lips, the tips of your ears, and the backs of your hands and neck. You need to use about an ounce of sunscreen to adequately cover your entire body.

• For the most protection, apply sunscreen 30 minutes before sun exposure and reapply it every 2 hours throughout the day. Also be sure to reapply it after swimming or exercising. Apply sunscreen to young children before they go outdoors, and teach older children and teens how to use sunscreen to protect themselves. Keep sunscreen in your car as well as with your gardening tools and sports and camping gear to remind yourself and your family to use it.

• Be an educated sunscreen consumer. Most sunscreens provide physical protection, chemical protection or a combination of both. Knowing the difference can help you select the best product for you and your family.

• Physical sunscreens contain ingredients such as titanium dioxide. These form an opaque film that reflects UV rays before they can penetrate your skin. Chemical sunscreens, on the other hand, absorb sunlight before it can cause any damage. Combination products do a little of both.

• Even if you know what to look for, sunscreen labels can be confusing, and sometimes actually misleading. That's why the Food and Drug Administration has instituted new labeling guidelines. Among the changes is the elimination of the terms sun block (no product actually "blocks" UV rays), all-day (no sunscreen lasts all day) and waterproof (all sunscreens wash off in water to some extent — the new term is water-resistant). Sunscreens claiming an SPF higher than 30 are now labeled 30+, rather than 45 or 60, because tests show little difference among products with SPF factors over 30. Finally, make sure any product you use actually contains sunscreen — many tanning oils and lotions don't. Products that don't contain sunscreen are required by law to clearly indicate that on the label.

• Wear protective clothing. Sunscreens don't provide complete protection from UV rays. That's why it's a good idea to also wear dark, tightly woven clothing that covers your arms and legs, and a broad-brimmed hat, which provides more protection than a baseball cap or visor. Some companies also design photoprotective clothing. Your dermatologist can recommend an appropriate brand. Don't forget sunglasses. Look for those that block out both UVA and UVB rays.

• Avoid tanning beds and tan-accelerating agents. Tanning beds emit UVA rays, which may be as dangerous as UVB rays, especially since UVA light penetrates deeper into your skin and causes precancerous skin lesions.

• Be aware of sun-sensitizing medications. Some common prescription and over-the-counter drugs — including antibiotics; certain cholesterol, high blood pressure and diabetes medications; birth control pills; nonsteroidal anti-inflammatories such as ibuprofen (Advil, Motrin, others); and the acne medicine isotretinoin (Accutane) — can make your skin more sensitive to sunlight. Ask your doctor or pharmacist about the side effects of any medications you take. If they increase your sensitivity to sunlight, be sure to take extra precautions.

• Have regular skin examinations. See your doctor for a complete skin exam every year if you're older than 40, or more often if you're at high risk of developing melanoma.

• Check your skin regularly and report changes to your doctor. Examine your skin often for new skin growths or changes in existing moles, freckles, bumps and birthmarks. With the help of mirrors, check your face, neck, ears and scalp. Examine your chest and trunk, and the tops and undersides of your arms and hands. Examine both the front and back of your legs, and your feet, including the soles and the spaces between your toes. Also check your genital area, including between your buttocks.

Alternative medicine refers to therapies that may be used instead of conventional treatments. Complementary or integrative medicine, on the other hand, usually means therapies used in conjunction with traditional treatments. These distinctions aren't firm, however, and the boundaries between types of therapies are constantly changing.

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