Skin Cancer Prevention
What are the major risk factors for developing skin cancer?
The major risk factor for developing skin cancer, primarily for basal cell carcinomas and squamous cell carcinomas, is ultraviolet exposure. Ultraviolet exposure, probably for basal cell carcinomas and squamous cell carcinomas, can account for 90-95% of all skin cancers. In order for ultraviolet exposure to have some effect, however, on the skin, the skin has to be susceptible. We grade skin based on skin type, 1 through 6, with 1 being the most sensitive to sun, and 6 being the least sensitive. So, the more likely that the patient will have ultraviolet damages, the more likely they will have a lower skin type number. Redheads clearly are more susceptible to skin damage from ultraviolet than people of pigment. This is a major factor that we see in defining which groups get skin cancer. In addition, it would be the behavioural changes of those that get a lot of sun and those that are more careful in the sun. There are other factors, including familial factors and genetic factors, but they're far outweighed by the two issues that I just explained.
How effective is sun block?
Sun block is an important part of our armamentarium to protect ourselves from ultraviolet damage and prevent skin cancer. It's extraordinarily important to note, however, that sunblock is the third thing that's important in protecting ourselves against skin cancer. The most important one is behaviour. The second most important one would be clothing. Where behaviour and clothing doesn't work, sunblock has a role. Trying to ask sunblock to protect ourselves from the sun is like asking an umbrella to protect yourself in a hurricane. It can't do it, particularly if you're out getting sun.
How much sun block should I use and how often should I use it to protect my skin?
Sun block needs to be applied an hour before you go outside, and it needs to be applied in probably double the quantity that most people apply it. The SPF factor, which is the sun protective factor, relates to the ability the sun block has to protect itself against ultraviolet B rays or the burning rays. In general, 15 is adequate for city wear. 30 would be more appropriate if you find yourself out for a long period of time in the midday, and even some of the higher numbers would be appropriate if you are our doing some sort of sun seeking behaviour or are in an area where you cannot avoid it, such as you are playing beach volleyball. These do not address, however, ultraviolet A exposure. The newer sun blocks do have ultraviolet A protection and they are important to look for. It will say on the sun block “full spectrum protection”. It might even say ultraviolet A and ultraviolet B protection. Most of the newer sun blocks will do so. Some of the things you want to look for are avobenzone, zinc, and titanium, and there are some newer additions from Europe that are coming out in this country that can even actually boost the sun protective factor.
Why is it important to keep a close watch on atypical moles?
Atypical moles are felt to be somewhat fragile, in the sense that they have a greater propensity for change. That change would not be a change toward normality, but rather a change toward abnormality, and so atypical moles do need to be watched and checked on some sort of monthly basis, preferably by the patient, and perhaps once or twice a year by a dermatologist. There are patients, as I mentioned, with multiple atypical nevi, and these people are at a much significantly greater risk of developing the malignant melanoma form of skin cancer.
