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Sunlight exposure: a cause of melanoma?

Robledo F. Rocha


On June 14th, the overwhelming majority of the audience in the Arena Amazonia for the England vs. Italy match, including me, cheered the Squadra Azzurra. That's because the England manager, Roy Hodgson, has said Manaus was the venue ideally to avoid, and that he preferred to be drawn in the most difficult group of the 2014 FIFA World Cup rather than had to play in the heat of the Amazon Rainforest.

As a matter of fact, I got another reason for have supported Italy. Nothing against what Hodgson said, once the hot and humid climate of Manaus certainly does not provide the ideal conditions for the best performance of the athletes. I felt particularly peeved by an English football commentator, who said that, besides dehydration and muscle cramping, exposure to the strong tropical sun of Manaus during the match can lead to the development of skin cancer, above all melanoma, to European football players.

I live near Manaus. Despite the native vegetal covering of my city is no longer a wet dense jungle, but a dry grassy savannah, the strong tropical sun is the same. Here, basal cell carcinoma and squamous cell carcinoma are found abundantly in the routine practice of every pathologist.

The same cannot be claimed for melanoma. Here, the incidence of melanoma does not exceed the Brazilian average, and the most common subtype is by far the acral lentiginous melanoma, for which exposure to sunlight is not a relevant risk factor. There might well be other factors interfering with the relationship between sun exposure and regional melanoma incidence, such as intense racial miscegenation and use of topical potent sunscreens.

Some will state that sunlight plays no role in the pathogenesis of melanoma, others will assert that exposure to ultraviolet solar radiation is the major environmental risk factor for melanoma. However, with the exception of the above mentioned English football commentator, everyone will agree that the ninety minutes lasting of a football match is insufficient to cause, alone, skin cancer, especially melanoma.


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Robledo F. Rocha


Dr. Hurt, I would appreciate if you explain in more details this point. I fell confused because what I witness in my everyday practice is not endorsed by the most influential literature, including acclaimed textbooks of melanocytic pathology.
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Robledo F. Rocha


Thank you, Dr. Hurt, for the reference. I'll certainly look for it.

As I said before, I feel confused about this issue. The Brazilian Melanoma Group, a private civil society, and the Brazilian National Cancer Institute, a governmental agency, still recommend the use of sunscreens for preventing the development of melanoma, despite both admit the expected protective effect has not so far demonstrated conclusive evidence in reducing the incidence of melanoma.

1) Burnett ME, Wang SQ. Current sunscreen controversies: a critical review. Photodermatol Photoimmunol Photomed. 2011;27:58-67.

2) Dennis LK, Beane Freeman LE, VanBeek MJ. Sunscreen use and the risk for melanoma: a quantitative review. Ann Intern Med. 2003;139:966-978.

3) Huncharek M, Kupelnick B. Use of topical sunscreens and the risk of malignant melanoma: a meta-analysis of 9067 patients from 11 case-control studies. Am J Public Health. 2002;92:1173-1177.

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