Not all melanomas can be prevented, but there are things you can do that could reduce your risk of getting melanoma.

Limiting ultraviolet (UV) exposure

The most important way to lower your risk of melanoma is to protect yourself from exposure to UV rays. Practice sun safety when you are outdoors. Simply staying in the shade is one of the best ways to limit your UV exposure. If you are going to be in the sun, Slip! Slop! Slap! and Wrap is a catch phrase that can help you remember some of the key steps you can take to protect yourself from UV rays:

• Slip on a shirt.
• Slop on sunscreen.
• Slap on a hat.
• Wrap on sunglasses to protect the eyes and sensitive skin around them.

Seek shade

An obvious but very important way to limit your exposure to UV light is to avoid being outdoors in direct sunlight too long. This is particularly important in the middle of the day between the hours of 10 am and 4 pm, when UV light is strongest. If you are unsure how strong the sun's rays are, use the shadow test: if your shadow is shorter than you are, the sun's rays are at their strongest, and it is important to protect yourself.

Keep in mind that sunlight (and UV rays) can come through light clouds, can reflect off water, sand, concrete, and snow, and can reach below the water's surface, so protect your skin whenever you are outdoors.

The UV Index: The amount of UV light reaching the ground depends on a number of factors, including the time of day, time of year, elevation, and cloud cover. To help people better understand the strength of UV light in their area on a given day, the National Weather Service and the US Environmental Protection Agency (EPA) have developed the UV Index. It gives people an idea of how strong the UV light is in their area, on a scale from 1 to 11+. A higher number means a higher chance of sunburn, skin damage, and ultimately skin cancers of all kinds. Your local UV Index should be available daily in your local newspaper, on TV weather reports, online (www.epa.gov/sunwise/uvindex.html), and on many smartphone apps.

Protect your skin with clothing

Clothes provide different levels of UV protection, depending on many factors. Long-sleeved shirts and long pants or skirts protect the most. Dark colors generally protect more than light colors. A tightly woven fabric protects better than loosely woven clothing. Dry fabric is generally more protective than wet fabric.

Be aware that covering up doesn't block out all UV rays. If you can see light through a fabric, UV rays can get through, too.

Some companies in the United States now make clothing that is lightweight, comfortable, and protects against UV exposure even when wet. These sun-protective clothes may have a label listing the ultraviolet protection factor (UPF) value the level of protection the garment provides from the sun's UV rays (on a scale from 15 to 50+). The higher the UPF, the higher the protection from UV rays.

Newer products, which are used in the washing machine like laundry detergents, can increase the UPF value of clothes you already own. They add a layer of UV protection to your clothes without changing the color or texture. This can be useful, but it's not exactly clear how much it adds to protecting you from UV rays, so it's still important to follow the other steps listed here.

Wear a hat

A hat with at least a 2- to 3-inch brim all around is ideal because it protects areas often exposed to intense sun, such as the ears, eyes, forehead, nose, and scalp. A dark, non-reflective underside to the brim can also help lower the amount of UV rays reaching the face from reflective surfaces such as water. A shade cap (which looks like a baseball cap with about 7 inches of fabric draping down the sides and back) is also good, and will provide more protection for the neck. These are often sold in sports and outdoor supply stores.

A baseball cap can protect the front and top of the head but not the neck or the ears, where skin cancers commonly develop. Straw hats are not as protective as ones made of tightly woven fabric.

Use sunscreen

Use sunscreens and lip balms on areas of skin exposed to the sun, especially when the sunlight is strong (for example, between the hours of 10 am and 4 pm). Sunscreens with broad spectrum protection (against UVA and UVB rays) and with sun protection factor (SPF) values of 30 or higher are recommended. Use sunscreen even on hazy days or days with light or broken cloud cover because UV rays still come through.

Always follow directions when applying sunscreen. Ideally, a 1-ounce application (about a shot glass or a palmful of sunscreen) is recommended to cover the arms, legs, neck and face of an average adult. Protection is greatest when sunscreen is used thickly on all sun-exposed skin. Sunscreens need to be reapplied at least every 2 hours to maintain protection. Sunscreens can wash off when you sweat or swim and then wipe off with a towel, so they might need to be reapplied more often be sure to read the label. And don't forget your lips; lip balm with sunscreen is also available.

Some people use sunscreens to stay out in the sun for long periods of time without getting sunburned. Sunscreen should not be used to spend more time in the sun than you otherwise would, as you will still end up with damage to your skin.

Remember that sunscreens are a filter they do not block all UV rays. The sunscreen's SPF number is a measure of how long it would take you to get sunburned, compared to how long it would have taken if you were not using it. For example, if you would normally burn after only 5 minutes in the sun, using a product with an SPF of 30 would mean you would still get burned in 150 minutes. And that's assuming that you applied it as directed, which unfortunately many people do not.

Sunscreens may help reduce your exposure to UV light and reduce your risk of melanoma. But there is no guarantee, and if you stay in the sun a long time, you are at risk of developing skin cancer even if you have put on sunscreen.

Wear sunglasses

Wrap-around sunglasses with at least 99% UV absorption provide the best protection for the eyes and the skin area around the eyes. Look for sunglasses labeled as blocking UVA and UVB light. Labels that say UV absorption up to 400 nm or Meets ANSI UV Requirements mean the glasses block at least 99% of UV rays. If there is no label, don't assume the sunglasses will give any protection.

Avoid tanning beds and sunlamps

Many people believe the UV rays of tanning beds are harmless. This is not true. Tanning lamps give out UVA and usually UVB rays as well, both of which can cause long-term skin damage and can contribute to skin cancer. Tanning bed use has been linked with an increased risk of melanoma, especially if it is started before the age of 30. Most dermatologists and health organizations recommend not using tanning beds and sun lamps.

If you want a tan, one option is to use a sunless tanning lotion, which can provide a darker look without the danger. These lotions contain a substance called dihydroxyacetone (DHA). DHA interacts with proteins on the surface of the skin to give it a darker color. You do not have to go out in the sun for these to work. The color tends to wear off after a few days. These products can give skin a darker color (although in some people it may have a slight orange tinge), but if you use one you still need to use sunscreen and wear protective clothing when going outside. These tans do not protect against UV rays.

Some tanning salons offer DHA as a spray-on tan. A concern here is that DHA is approved for external use only and should not be inhaled or sprayed in or on the mouth, eyes, or nose. People who choose to get a DHA spray tan should make sure to protect these areas.

Protect children from the sun

Children need special attention, since they tend to spend more time outdoors and can burn more easily. Parents and other caregivers should protect children from excess sun exposure by using the steps above. It's important, particularly in parts of the world where it is sunnier, to cover your children as fully as is reasonable. You should develop the habit of using sunscreen on exposed skin for yourself and your children whenever you go outdoors and may be exposed to large amounts of sunlight. Children need to be taught about the dangers of too much sun exposure as they become more independent.

Babies younger than 6 months should be kept out of direct sunlight and protected from the sun with hats and protective clothing. Sunscreen may be used on small areas of exposed skin only if adequate clothing and shade are not available.

A word about sun exposure and vitamin D

Doctors are learning that vitamin D has many health benefits. It may even help to lower the risk for some cancers. Vitamin D is made naturally by your skin when you are in the sun. How much vitamin D you make depends on many things, including how old you are, how dark your skin is, and how strong the sunlight is where you live.

At this time, doctors aren't sure what the optimal level of vitamin D is. A lot of research is being done in this area. Whenever possible, it is better to get vitamin D from your diet or vitamin supplements rather than from sun exposure, because dietary sources and vitamin supplements do not increase risk for skin cancer, and are typically more reliable ways to get the amount you need.

For more information on how to protect yourself and your family from UV exposure, see our document Skin Cancer: Prevention and Early Detection.

Watching for abnormal moles and having them removed

Certain types of moles have an increased risk of developing into melanoma (see the section What are the risk factors for melanoma skin cancer?). If you have moles, depending on how they look, your doctor may want to watch them closely with regular exams or may remove some of them if they have certain features that suggest they might change into a melanoma.

Routine removal of many moles is not usually recommended as a way to prevent melanoma. Some melanomas may develop from moles, but most do not. If you have many moles, getting careful, routine exams by a dermatologist, along with doing monthly skin self-exams, might be recommended.

If you find a new, unusual, or changing mole, you should have it checked by a doctor experienced in recognizing skin cancers. See the section Can melanoma skin cancer be found early? for descriptions of what to look for.

Genetic counseling and testing for people at high risk

Gene mutations (changes) that increase melanoma risk can be passed down through families, but they account for only a small portion of melanomas. You might have inherited a gene mutation that increases your risk of melanoma if any of the following apply:

• Several members of one side of your family have had melanoma
• A family member has had more than one melanoma
• A family member has had both melanoma and pancreatic cancer
• You have had more than one melanoma

Genes such as CDKN2A (also known as p16) have been found to be mutated in some families with high rates of melanoma. Tests for these gene changes are now available, although they are not widely recommended by doctors at this time. People interested in learning whether they carry gene changes linked to melanoma may want to think about taking part in genetic research that will advance progress in this field.

It is very important to meet with a genetic counselor before deciding if you should have testing. The genetic counselor can describe the tests to you and explain what the results may or may not tell you about your risk. Genetic testing is not perfect, and in some cases the tests may not provide solid answers. See Genetic Testing: What You Need to Know for more on this.

Because it's not clear how useful the test results might be, most melanoma experts do not recommend genetic testing for people with a personal or family history of melanoma at this time. Still, some people may choose to get tested. In any event, people with a family history of melanoma should ask their doctor about getting regular skin exams, learning to do skin self-exams, and being particularly careful about sun safety.

- cancer.org
http://www.cancer.org/cancer/skincancer-melanoma/detailedguide/melanoma-skin-cancer-prevention