Preventing Sunburn and Cancer This Summer

July 2012

By far the best way to avoid disease is to prevent its ever happening. This type of prevention is commonly called “primary prevention,” in contrast to “secondary prevention,” where one detects disease not yet apparent, and reverses it, like finding a skin cancer and curing it by cutting it out. The latter is typically much more costly in terms of money and pain, than is prevention before the problem ever appears in the first place. Preventing skin injury by avoiding sunburn and tanning booth damage is an effective primary prevention of skin cancers.

I had reddish hair as a youngster and recall several times I was sunburned so badly that I had painful blisters and peeling. No sunblock in those days; and why didn’t my parents make me wear a t-shirt? I’m sure most readers have had similar experiences. Undoubtedly those burns and others caused a small skin horn to develop on my nose 10 years ago; on surgical removal, it proved to be a squamous cell cancer. Tough to watch it being cut off the bridge of one’s nose, but no recurrence there or new ones elsewhere so far.

Sunburn can markedly increase the risk of developing skin cancers, with the risk increasing each year for decades. The worse and more frequent the burns, the greater the risks. Basal cell cancers are the most commonly associated with sun exposure (over 500 000 cases/yr. in the US), squamous cell cancers the next most common (over 100 000/yr.), and the very dangerous malignant melanomas slightly less frequent (75 000/yr.).

Sun light contains both ultra violet A (UVA) waves (shorter wave lengths than visible light waves) and even shorter length UVB waves.
UVB causes sunburn to appear over the 48 hours after exposure and ultimately causes tanning (increased skin pigment), providing some future protection from further burns. Therefore tanning booths use predominantly UVB light. UVB light causes direct and greater damage to the skin connective tissue and the cellular genetic material (DNA).  This DNA damage, over time, can cause transformations into skin cancers.

UVA light does cause a temporary tan without increasing total skin pigment and was previously thought to do little harm. But recent research has shown that it too causes connective tissue injury and indirect DNA damage by creating toxic chemical ions (free radicals). Hence, it also increases skin cancer risks, especially those for melanoma.

Both UVA and UVB exposure also cause damage to the skin collagen and elastic tissue over time, hence markedly increasing wrinkling to the point that heavily sun-exposed people can look decades older than their real age.

UVB light can be blocked by sunscreens. But UVA damage is not prevented by our standard sunscreens, although some are now including and rating their UVA blocking effect, probably unreliably. Opaque blockage works best, like clothing (if you can’t see through it, it’s good) and that white zinc or titanium oxide cream city folks wear on their noses.

So what does all this mean? Simple:

  • don’t get sunburned; you’ll still tan even with sunblock.
  • use sunblock with a sun protection factor (SPF) rating of at least 15 and up to 50-70 in intense summer sun, especially on heavily exposed areas like backs of ears and hands, nose, lips, and temples. Apply it several times (at least 2) a day
  • use protection against UVA as well, as much as you can; wide brimmed hats, clothing, and/or zinc oxide
  • use protection for sure during the most crucial times of day, between 9 am and 3 pm, when the sun’s rays are most intense
  • children, young adults, and fair complected (especially red-haired) individuals need the most protection
  • don’t use tanning booths
  • be vigilant for sun-exposed area sores that don’t heal, or bleed, or grow over the course of months. Any black or blue color in them is especially worrisome for melanoma, from which one can die. The other types just need whacking off before they get larger and more troublesome.

Dan Onion: 293-2076,
Vienna Health Officer

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