Sun: Risks and Care
A study published in the journal Cancer Epidemiology, Biomarkers & Prevention (CEBP) proposes that in a cohort of 108,916 white women, those who had a minimum of 5 severe sunburn incidents between the ages of 15 and 20 had an increased risk of all skin cancers
Dr. Abrar A. Qureshi, professor and chair of the Department of Dermatology at Warren Alpert Medical School of the Brown University and Rhode Island Hospital: An individual's risk of developing skin cancer depends on both host and environmental risk factors. Persons with high host-risk traits, such as red hair color, a higher number of moles and high sunburn susceptibility should pay more attention to avoid excessive sun exposure, especially early in life."
Skin cancer etiology is linked to age, sex, skin type, hair and eye color, family history and genetic conditions. However, the highest percentage of cases are considered to be linked to lifestyle choices including ultraviolet (UV) radiation from sun exposure, UV radiation from tanning beds, obesity, exposure to coal tar pitch, soot, mineral oils and shale oils, arsenic and inorganic arsenic compounds.
"Our results suggest that sun exposures in both early life and adulthood were predictive of non-melanoma skin cancers, whereas melanoma risk was predominantly associated with sun exposure in early life in a cohort of young women."
"Parents may need to be advised to pay more attention to protection from early-life sun exposure for their kids in order to reduce the likelihood of developing melanoma as they grow up," says Dr. Qureshi. "Older individuals should also be cautious with their sun exposure because cumulative sun exposure increases skin cancer risk as well."
Recent regulations from the US Food and Drug Administration (FDA) on sunscreen products propose that sunscreen labeling be expanded to include a 4-star rating system to inform consumers how well a product protects them against ultraviolet A (UVA) light and provide information on alternative ways people can limit their risks to sunlight overexposure, such as limiting the time in direct light or wearing protective clothing.
The steps are being taken to help protect consumers from sun damage, prevent sunburn, and reduce the risks of skin cancer and early skin aging.
The FDA also want to make changes regarding protection against ultraviolet B (UVB) light with a proposal for amending their existing rule on UVB products to increase the maximum sunburn protection factor from SPF 30+ to SPF 50+.
Moreover, researchers conducted the world's first study to assess the molecular impact of sunscreen found it offers 100% protection against all three types of skin cancer - basal cell carcinoma, squamous cell carcinoma and malignant melanoma. They also found sunscreen prevents damage to a key anti-cancer gene known as p53.
There is lots of evidence that sunscreen stops skin from getting sunburn, but not much is known - although there is much speculation - about whether it can prevent skin cancers.
In the journal Pigment Cell & Melanoma Research, researchers from Australia's Queensland University of Technology (QUT) report how they looked at the molecular effect of sunlight on human skin, both with and without sunscreen.
They found that when sunscreen (SPF30+) was properly applied to exposed skin, there was no evidence of UV-induced damage.
But they also found sunscreen has another effect - it protects the p53 gene from DNA damage that mutates it into a form where it can no longer do its job of repairing skin cells whose DNA has been damaged by the sun. Once skin cells have DNA damage, there is a higher risk of skin cancer.
Lead researcher Dr. Elke Hacker says:
"Melanoma is the most lethal form of skin cancer with research showing damage of melanocytes - the pigment-producing cells of the skin - after sun exposure plays a role in the development of skin cancer."
For their study, the researchers recruited 57 patients who were having a series of skin biopsies and assessed molecular changes in their skin before and after exposure to UV, with and without sunscreen.
They first took biopsies of two sites on unexposed skin, then applied sunscreen to one site and left the other site bare while they exposed them to UV light. They then took biopsies of both sites again.
Then, after 24 hours, they took another set of biopsies and compared the skin samples, says Dr. Hacker, who explains what they found:
"... after 24 hours where the sunscreen had been applied, there were no DNA changes to the skin and no impact on the p53 gene."
She says this is an important discovery because they found something about sunscreens and their effect on skin that goes beyond protecting against the redness of sunburn.
The study "looks beyond the redness to determine whether UV exposure when using sunscreen causes molecular changes to the skin, as these changes have been linked to basal cell carcinoma, squamous cell carcinoma and malignant melanoma. When there are changes in the molecular structure it can enhance skin cancer development," says Dr. Hacker.
The researchers believe their findings also set a benchmark for investigating "super sunscreens" that help repair skin damaged from sun exposure.
The study was funded by Cancer Council Queensland, who recommends before going out in the sun, people put on SPF30 or above, broad-spectrum, water-resistant sunscreen, and reapply it every 2 hours.
It's also important to complement sunscreen with sun protective clothing, a broad-brimmed hat, to seek shade and slide on wraparound sunglasses for best protection."
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