Guide to Skin Cancer Prevention: Update on Sun Protection and Early Detection
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Guide to Skin Cancer
Prevention: Update on Sun
Protection and Early Detection
Emily Y. Chu, M.D., Ph.D.
Assistant Professor of Dermatology &
Pathology and Laboratory Medicine
Hospital of the University of Pennsylvania
May 17, 2019
17th Annual Focus on Melanoma Conference
Philadelphia, PA
Summer is coming…
Protect yourself from the sun
Protecting your skin from the sun is the best
strategy to help prevent melanoma and other
skin cancers
What’s the single best way to protect yourself from the sun? 1) Avoid sun exposure 2) Sun-protective clothing 3) Sunscreen
Sun Avoidance
Early Morning Noon Late Afternoon
Earth
Early Morning Noon Late Afternoon
Sun’s rays at noon have
the least distance to travel
through the atmosphere
Earth
Early Morning Noon Late Afternoon
AVOID
10 am - 4 pm
Earth
True or False:
Beach umbrellas provide
sufficient sun protection over
an extended period of time
1. True
2. FalseJAMADermatol.2017;153(3):304-308 • 81 participants – randomized to use beach umbrella only versus sunscreen only • 142 sunburns in the umbrella group, vs 17 in the sunscreen group • CONCLUSION: A beach umbrella alone may not provide sufficient protection for extended UV exposure
Clothing is better than
sunscreen
Ghazi S et al. Journal of the German Society of Derm 2011Sun protective clothing:
how does it work?
• Construction
– Dense, tight construction minimizes space between
yarns = less UV light passing through
• Dyes
– Some dyes deflect more UV radiation than others
• Treatments
– UV absorbing or blocking agents may be added to
clothing
• Fiber type
– Polyester > nylon > wool, silk > cotton, rayon
• Other factors: Stretch, Wetness, ConditionUPF: Ultraviolet Protection Factor
• Rating system used for apparel
– Indicates how effectively fabrics shield from UV rays
– Gauges effectiveness against both UVA and UVB
rays
– Higher the UPF, the better the protection
Protection UPF Ratings Approximate UV
Blocked
Good UV Protection 15-24 93-96%
Very Good UV Protection 25-39 96-97%
Outstanding UV 40-50+ 97-99%
ProtectionWhere do you find sun protective clothing? Almost anywhere
Invest in sun protective clothing
Sun Threadz
Colleen Dougherty Bronstein
Supporter of Melanoma
Program at Abramson
Cancer Center of the
University of PennsylvaniaWhat about sunscreen?
Regular sunscreen use has been shown to decrease risk for squamous cell cancer and melanoma Green AC et al. J Clin Oncol 2011;29;3:257-263
Most of us do not apply adequate amounts of sunscreen
FDA regulations on sunscreen labels
“Broad spectrum” refers
combined UVA and UVB
protection
SPF number only
indicates a sunscreen's
effectiveness against
UVB rays (the UV light
that can burn skin)
How much time you can get the
stated SPF level of protection while
swimming or sweating:
Water resistant: 40 minutes or 80
minutes of protectionSPF: Sun Protection Factor
• Rating system for sunscreen
– SPF is a ratio of the dose of UV radiation that induces
the first perceptible redness on the skin with
sunscreen to the dose without sunscreen
– Higher the SPF, the better the protection
Percentage of UVB Proportion of UV
SPF Rating
blocked radiation that reaches
the surface of skin
15 93.3% 6.7%
30 96.7% 3.3%
60 98.3% 1.7%Sunscreen: chemical versus physical
blockersSunscreen is
the most
effective anti-
aging product
you can put on
your skinSunscreen tips • The best sunscreen is the one you will use • Apply 15-30 minutes before you go outside • Apply liberally: “shot glass rule” • Reapply every 2 hours, and/or after swimming or sweating
• 24 participants randomized to 4 different chemical sunscreen products, each applied to 75% of body surface area 4 times a day for 4 days • Blood levels of sunscreen ingredients measured • RESULT: Blood levels of sunscreen ingredients greater than the FDA threshold for waiving some toxicology studies
What’s the bottom line? • The study did not examine health effects of sunscreen in the blood • These sunscreen ingredients have been used for decades without known adverse health effects in humans • The American Academy of Dermatology continues to encourage sunscreen use as part of sun protection regimen
Protect yourself from the sun
Early Detection
Keys for early detection of
melanoma
• Know what to look for
– ABCDEs
– “Ugly duckling” moles
– New or changing dark spots
• Examine your own skin monthly
• Have your doctor examine your skin at
least once per year“I’ve got so many moles,
there’s no way I can remember if a spot is new
or changing!”Total body photography:
Provides a fixed reference point to
detect new or changing lesions
www.skintography.com
Feit NE et al. British J of Derm 2004;150:706-714.A promising new tool: MelaSight
• Developed by Andrew Marek
while he was a medical
student at Penn
• Import existing professional
skin exam photos
• Secure photo viewing
(username/password,
encryption, on device
storage)
• Mole mapping (flag, create
notes, and take close-up
photos of suspicious spots)
• Skin reference (how to
perform a skin exam, what to
look for)
Marek et al, JAAD 2018• Usual care consisting of TBP prints and digital photographs is an effective method of increasing skin self examination rates • Adding a mobile app is just as effective but associated with improved satisfaction
Other apps which may be helpful
• Mole Mapper
– Developed by
dermatologists at OHSU
– Available through the
iTunes app store for
$1.99
– Guides patients in taking
their own total body
photographs (with the
help of a family member
or friend)
– Helps the user to map,
measure, and monitor
skin molesWhat about artificial intelligence? • Convolutional neural network (CNN) outperformed 58 dermatologists in making accurate diagnoses of melanomas and benign nevi based on 100 dermatoscopic images • Caveat: The CNNs are only as good as their training, provided by humans
A team approach to skin care: integrating
technology into practiceKeys for early detection of
skin cancer
• Know what to look for
– Pink spots that persist and/or bleed
– ABCDEs
– “Ugly duckling” moles
– New or changing dark spots
• Examine your own skin monthly
• Have your doctor examine your skin at
least once per yearThank you!
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