Melanoma is one of the most common cancers to affect Americans.
The Skin Cancer Foundation reports that “Over the past three decades, more people have had skin cancer than all other cancers combined.” (1).
But recent studies suggest that these statistics may be skewed.
Over-Diagnosing Melanoma Cancer
A 2009 study in the British Journal of Dermatology found that sun exposure may not be the true cause of skin cancer, not in the way we understand it (2).
They found that the increase in skin cancer lesions reported in the United States doesn’t correspond truly malignant lesions. It was discovered that health professionals are quick to diagnose patients with cancer even if their moles are non-cancerous.
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The researchers concluded: “The distribution of the lesions reported did not correspond to the sites of lesions caused by solar exposure. These findings should lead to a reconsideration of the treatment of ‘early’ lesions, a search for better diagnostic methods to distinguish them from truly malignant melanomas, re-evaluation of the role of ultraviolet radiation and recommendations for protection from it, as well as the need for a new direction in the search for the cause of melanoma.”
What’s more, the relatively stable cases of deaths caused by skin cancer did not correspond to the ever-increasing number of patients suffering from the disease.
A review of 4,000 cases found that there was an annual increase of 9.39 to 13.91 cases per 100,000 per year between 1991-2004. The researchers concluded that this increase was mainly due to an over-diagnosis of non-cancerous lesions.
They wrote: “There was no change in the combined incidence of the other stages of the disease, and the overall mortality only increased from 2.16 to 2.54 cases per 100,000 per year … We therefore conclude that the large increase in reported incidence is likely to be due to diagnostic drift, which classifies benign lesions as stage 1 melanoma.”
The Melanoma-Sun Exposure Link
Cancer charities and research groups have been telling us for years that sun exposure causes skin cancer, but this isn’t entirely true.
While the damage caused by sunburns can contribute towards abnormalities in the skin and melanoma, research shows that high skin cancer rates are affecting a very specific population: indoor workers with light skin.
Experts argue that there’s almost no evidence at all to support the claim that sun exposure causes melanoma. Several studies have also found that regular sun exposure helps prevent skin cancer. This is because regular sun exposure allows you body to adapt to the harsh effects of the sun while also boosting your vitamin D levels ( a cancer-fighting vitamin), which your body produces when your skin catches some rays (3).
An article in the prestigious scientific journal The Lancet argues that melanoma occurrence has been found to decrease with greater sun exposure, and can be increased by sunscreens. The author argues that indoor workers receive 3-9 times less UV exposure than outdoor workers yet only indoor workers have increasing rates of melanoma (4,5).
To explain, the sun produces both UVA and UVB rays. Both rays cause tanning and burning. UVB rays allow your body to produce vitamin D, but they burn your skin more quickly. UVA rays penetrate your skin more deeply and lead to photoaging, wrinkles and skin cancers.
Most windows block out UVB rays, but allow UVA rays to penetrate through.
The researchers responsible for the latest studies on the subject of skin cancer and sun exposure said:
“We hypothesize that one factor involves indoor exposures to UVA (321–400nm) passing through windows, which can cause mutations and can break down vitamin D3 formed after outdoor UVB (290–320nm) exposure, and the other factor involves low levels of cutaneous vitamin D3.
After vitamin D3 forms, melanoma cells can convert it to the hormone, 1,25-dihydroxyvitamin D3, or calcitriol, which causes growth inhibition and apoptotic cell death in vitro and in vivo.
… We agree that intense, intermittent outdoor UV overexposures and sunburns initiate CMM [cutaneous malignant melanoma]; we now propose that increased UVA exposures and inadequately maintained cutaneous levels of vitamin D3 promotes CMM.”
Using The Sun To Your Advantage
The key principle in healthy sun exposure is to spend as much time in the sun as you can and never get burned. If you have light skin, this may be only 10-20 minutes during peak UVB hours (10am-1pm). If you have darker skin, it may take your body some time to reach peak vitamin D production.
Sunscreen and long-sleeved clothing can stop the rays in their tracks, so make sure to give the sun some real estate by exposing your arms and/or shoulders while outside. If you’re going to be outside for long period of time, soak up the sun for a bit and cover up or apply some homemade sunscreen to protect your skin from burning.