Our efforts to increase melanoma education often include clearing up various misconceptions about the disease. Those who’ve never been taught much about skin cancer tend to make incorrect assumptions about it.
One of these beliefs is that melanoma incidence is highest in southern states, and among people who consistently spend time out in the sun. While it is true that skin cancer impacts both, it’s not the whole truth.
The sun’s harmful UV (ultraviolet) rays can be just as dangerous, if not even more so, to northern U.S. residents as they are to those who live in the south. And with reason.
There is a scientific hypothesis that those who inhabitant northern and central states are more prone to developing melanoma than people living in sunbelt states, due to intermittent sun exposure.
Scientists believe that the populations of sunbelt states can become more acclimated to UV rays because their skin is more likely to be exposed to them year-round. Non-medically, it’s similar to the way an auto mechanic at some point builds up a tolerance to the smell of gasoline.
Some examples of intermittent (sporadic, occasional) sun exposure include:
- Spending much of the winter months indoors, then exposing skin to strong sunlight during the summer months
- Spending the entire workweek indoors, and then full weekends outdoors
- Northern and U.S. state residents vacationing in tropical or semitropical locations like Mexico, Florida, the Caribbean, or other areas where UV rays are particularly intense
Statistics show that when all ethnic groups are considered only one sunbelt state, Georgia, ranks within the Top 10 states for melanoma occurrences. And when only non-Hispanic Caucasians are included, only two states make that Top 10 list: Georgia again, and Hawaii.
This chart shows the Top 10 melanoma state rankings:
Source: Center for Disease Control (CDC)
The skin cancers that are less serious than melanoma (basal cell carcinoma and squamous cell carcinoma) are more prevalent in sunbelt states.
It’s important to note that this information doesn’t mean that southerners shouldn’t continue to take sun-safety precautions; they certainly should. It means that northerners should remind themselves that the cold is no shelter from melanoma.Intermittent Sun Exposure and Melanoma Risk
Benign moles (or nevi) are so common that pretty much every human being on earth has them. In the language of medicine, “benign” means noncancerous. However, exposure to dangerous ultraviolet (UV) rays from our sun can create mutations on moles that cause nevi to turn from safely benign, to dangerously malignant (cancerous). UV rays even often promote a common mole’s formation to begin with.
In a report cited within an article posted by the Helen Diller Family Comprehensive Cancer Center, researchers in California have discovered a way to determine the direction moles take as they transform from skin lesions (“precursors”) to reaching their fully malignant, potentially fatal, forms.
This easy to remember chart shows the progression to melanoma upon UV exposure:
Normal mole (1 mutation) —> Atypical mole (several mutations) —> Melanoma (many mutations).
It was the data gathered by this group of scientists that confirmed the negative impact UV rays have on skin by initiating the growth of moles, as well as turning them cancerous. It also confirmed the existence of “intermediate lesions”, which are lesions whose benign or malignant status is not easily determined. The latter discovery will be greatly beneficial to dermatologists when choosing the treatment for their melanoma patients.
So, what does all of this mean to those of us who are non-medical laypersons? That has been neatly summarized by the words of Dr. Boris Bastian; the report’s senior author:
“A lot of melanomas have been sequenced at this point, and while it’s clear they carry UV-induced mutations, no one knew when they occurred…This study shows that they occur in benign moles, in the melanoma that arises from these moles, and in intermediate lesions. UV both initiates and causes the progression of melanoma, so exposing even benign moles to the sun is dangerous.”
Just because a mole is benign doesn’t mean it will stay that way. It’s very important to always take the appropriate skin protection precautions whenever we’re exposed to the sun.
Moles and Sun: A Dangerous Combination
*Additional information sources: University of California San Francisco, Helen Diller Family Comprehensive Cancer Center
Even among those who make a concerted effort to practice sun-safety, there remains a tendency to forget about the impact that secondary, or indirect, sun exposure has on our skin.
If there’s a choice to stand in the sun or in the shade, certainly the latter is preferred. But shade alone isn’t nearly enough to keep us adequately protected from harmful UV rays. Also, the amount of protection shade provides can vary substantially based upon factors such as the object(s) providing it, your location, time of day and the environment around you.
The singular point to remember most is that it’s still very possible for us to incur significant sun skin damage- even while fully in the shade.
There are multiple scenarios within which we may not realize the actual amount of UV rays to which we’re being subjected.
With that in mind, we would like to focus on three important types of indirect sun exposure; Reflected, Scattered and Diffuse.
Reflected is pretty much just what it sounds like. UV rays reflect off many things such as sand, snow, concrete, water, asphalt, ice and light surfaces; among others. So even if you’re sitting or standing under an umbrella (or parasol), or a tree(s), et cetera, your skin is still absorbing the rays being reflected onto it.
UVB rays emanate from our sun, and then once they’re within our atmosphere they can be “scattered” throughout the sky at a higher volume than we realize. If you are outside in a shaded area but can see blue sky, you are receiving scattered UV radiation.
Many people have the misconception that if it’s cloudy, hazy or overcast outside, they have a natural protection from sun exposure. Unfortunately, that isn’t true. And thinking that it is can lead to severe skin damage. The truth is that hazy sunlight may expose your skin to even more UV radiation than sunlight on a clear day.
Within this article we’ve shed some light (no pun intended) on a few of the biggest myths that people believe about skin damage; such as that you cannot get sunburned in the shade or in the haze.
However, to highlight those points, here are four pictures of common scenes at which one would be impacted by indirect sun exposure when you are in shade:
Please keep in mind that even if we’re unaware, the sun’s harmful rays will always be there.