[LIVE BLOG – Seattle] Myths and Truths About Sun Protection w/ Alan Fleischer, MD
Sun protection education can be a key factor to lessening the climbing numbers of skin cancer patients in the US. Misguided or misinformed Americans are lathering up and laying in the sun, unaware that what they know as sun protection facts are, often, just myths. Dr. Alan Fleischer works to provide information about UV rays, improper sunscreen use and offers a few tips on how we may have something to learn from the hat-wearing Australians.
Learn from Australia
In Australia, the skin cancer capital of the world, they teach protection: “Slip – on a shirt”; “Slop – on some sunscreen”; “Slap – on a hat.” Australian kids are often prohibited to go outside without a hat.
Pump dispensers of sunscreen are widely available in schools and use in encouraged. In the US, hats are prohibited but hand sanitizer is widely available.
Remember: Language of UVA vs. UVB
UVA range 315-400nm vs. UVB range 280-315nm
An international standard measurement of the strength of the solar UV radiation at a particular place on a particular day.
The UV Index in Seattle is 8 (considered very high).
Milwaukee vs. Miami: both have high index but Miami’s high times last longer.
North Carolina has a comparable UV with Northern Africa
Interesting Fact: There is no good epidemiological evidence that causally links burns with cancer. There is a difference between association and causation.
Definition: “Sun Protection Factor” (SPF)
In the US, sunscreens are measured with SPF.
SPF = ____Solar simulator dose to burn with sunscreen___
Solar simulator dose to burn without
Burns lead to Pain, but are not likely harmful!
Burns are an adaptive mechanism that allows for cellular auto-destruction in the event of high intensity UV exposure. In other words, the epidermis kills itself → Dead cells don’t reproduce!
1. Daily Sunscreen Usage Reduces Actinic Keratoses (Nonmelanoma Cancer)
2. Daily Sunscreen Usage Reduces Melanoma Risk By 50% Over 14 Years
In Dr. Fleischer’s favorite study: 1621 randomly selected people in Queensland, Australia were randomized to apply either daily or discretionary sunscreen. In a 14 year follow-up of the study population, it was shown that:
→ Daily sunscreen reduces melanoma risk by 50% over 14 Years
But, even better…Depth of invasion was also tracked:
→ There was a greater than 70% reduction in occurrence of thick melanomas for daily sunscreen usage.
“But I Wear Sunscreen!” 3 Issues:
1. People Don’t Cover Skin Well.
2. People Don’t Use Sunscreen Enough!
3. People Don’t Wait Long Enough to Let Sunscreen Soak into Skin!
- Remember: Products require 15 to 30 min to soak into the skin.
- Let the sunscreen soak in! Dr. Fleischer has personally observed numerous MDs and PhDs apply product to themselves (or kids) and then immediately jump into the pool. “That’s an excellent way to remove your sunscreen!
Sunscreens Products are mislabeled with reference to natural sunlight
- A study assessed efficacy of products to a variety of natural sunlight spectra. The products tested always provided less protection in natural sunlight, and the deviation from labeled value was greatest when the sun was low in the sky. The maximum deviation from labeled value was a factor of 2.
Clothing is a Critical Component to Comprehensive Cancer Prevention
- Skin cancers are uncommon in double-covered areas. The average weight t-shirt provides an SPF of about 5.
African-Ancestry Skin & Sun Observations
- Dr. Fleischer has removed over 8,000 skin cancers in those with European ancestry, and only 10 in African-ancestry. Most people with African skin maintain 4x the protection of european-ancestry people. That is, the skin gets as much UV damage in 280 years as an Irish ancestry person gets in 70 years.
Tans do confer some solar protection…BUT…the “Base Tan” is a Myth.
In one study, 12 sessions in a tanning bed provided a protection factor of 3.2 against UVB-induced erythema. Many people stop all solar protection approaches when tan, yet damage continues — de-bunking the myth of the “base tan.”
What about tanning beds?
Unlike sunshine, tanning units operate 365 days/yr.
Most people display reasonable modesty in sunshine, but expose all in tanning units.
In 2009, the WHO classified tanning beds in the same oncogenic category as cigarettes, as radium.
A Snapshot of Dr. Fleischer’s Recommendations
1. Hats and protective clothing really do work!
2. Sunscreens: For prolonged exposure use a broad spectrum sunscreen with SPF > 30, note: those which are very water resistant or “sport” products have high substantivity
3. Sunscreen reapplication is only needed for poor initial applications.
[Image by Vinoth Chandar]