The link between UV radiation and Skin cancer

Skin is a very important part of our body, perhaps the largest organ and it is impossible to imagine a person without any skin. Ultraviolet radiation (UVR) is the part of the electromagnetic spectrum with wavelengths between 100 and 400 nanometers (shorter than visible light) which makes it invisible to the naked eye.

The sun gives off 3 types of UV rays:

  1. UV-A rays (long-wave uv): UV-A rays penetrate the skin deeply, affect connective tissue, and cause the skin to sag and wrinkle, and UV-A rays may help cause skin cancer.
  2. UV-B rays (sunburn uv): UV-B rays affect the top layer skin and cause sunburn, skin cancer and cataract. UV-B rays are more prevalent at midday.
  3. UV-C rays (short-wave uv): UV-C rays are extremely dangerous but do not reach the earth’s surface due to absorption in the atmosphere.

How UV radiation causes skin cancer?

  1. At any rate, UV-A rays are believed to increase the effects of UV-B rays, which are the primary cancer causing rays.
  2. UV-A causes damage to DNA in dermis and UV-B in epidermis.
  3. This causes mutation in a tumor supressor gene (p53) which is protective gene that normally limits the growth of tumors.
  4. Hence, a normal skin cell may begin to grow in the uncontrolled, disorderly way of cancer cells.
  5. The most common warning sign of skin cancer is a change in the appearance of the skin, such as a new growth or a sore that will not heal.

Protective measures:

“People don’t get checked enough. What scares me is that a lot of people with skin cancer came in for something different and I just happened to see the tumor.” – Dr. Quang Le

The incidence of skin cancer is relatively very high in Australia and New Zealand and among fair skinned people. But, no matter where you live, and what color you are, you need to take the following steps to protect yourself from the sun:

1. Sunscreen: Use a broad-spectrum sunscreen that protects you from both UV-A and UV-B radiation, and has a sun protection factor (SPF) of at least 15. This means that it will take 15 times longer before you will burn compared to time of sun exposure that would burn you. Children should use a higher SPF such as 30 or 45 (a sun block).

2. Clothing: Choose fabrics with a tight weave, and wear a wide-brimmed hat. Wherever the ozone layer is thinner than usual, even more protection is required. In Australia, because of a thin ozone layer due especially to the Earth’s rotation, schoolchildren are allowed outside for recess only if they wear a wide-brimmed hat and long sleeves.

3. Time: Sun exposure can be reduced by changing patterns of outdoor activities to reduce time of exposure to high-intensity UV radiation. Stay out of the sun altogether between the hours of 10 A.M. and 3 P.M. It is believed that this action will reduce annual exposure to the sun’s rays by as much as 60%.

4. Sunglasses: Wear sunglasses that have been treated to absorb both UV-A and UV-B radiation. Otherwise, darkened sunglasses can expose the eyes to more damage than usual because the pupils dilate in the shade. For this reason, do not let children wear “fun” sunglasses outside in the sun.

5. Avoid tanning: Avoid tanning machines unless prescribed by a physician for Seasonal Affective Disorder (SAD). Although most tanning devices use only high levels of UV-A radiation, the deep layers of the skin become more vulnerable to UV-B radiation upon later exposure to the sun.

Hence, children should be encouraged to use sunscreen, wear appropriate clothing and avoid both the strongest midday sun levels and indoor tanning.

Read details about the types of skin cancer

2 Comments
  1. July 21, 2011
    • July 23, 2011

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