There is very little proof that sunscreen minimizes cancer malignancy in dark-skinned people.
Cancer malignancy is a potentially deadly kind of skin cancer that affects individuals of every ethnic and racial group. Direct exposure to ultraviolet, or UV, rays from the sun is the risk factor most closely linked to developing cancer malignancy. Sunburns have been associated with doubling ones danger of melanoma.
It ultimately might minimize the threat of establishing cancer malignancy because sun block can obstruct UV rays and therefore reduce the danger of sunburns. The promo of sun block as an efficient melanoma prevention method is a reasonable public health message.
This might hold true for light-skinned individuals, such as people of European descent, however this isnt the case for darker-skinned individuals, such as people of African or Asian descent.
By Adewole S. Adamson, University of Texas at Austin
August 10, 2022
Melanoma is a possibly fatal kind of skin cancer that impacts people of every ethnic and racial group. Even amongst white individuals, there is no relationship in between sun exposure and the threat of acral cancer malignancies. Notoriously, Bob Marley died from an acral melanoma on his big toe, however sunscreen would not have actually assisted.
2 years ago my research study group conducted a methodical evaluation in which we evaluated all of the released medical literature associated to UV exposure and melanoma in people of color. Many dermatology and skin cancer-focused companies– including a few of which I belong to– promote the public health message of sun block use to minimize melanoma threat amongst black patients.
The general public health messages promoted by lots of clinicians and public health groups regarding sunscreen suggestions for dark-skinned individuals are not supported by the readily available scientific evidence. Media messaging aggravates the issue with headline after headline warning that black individuals can also develop melanoma which black people are not immune.
To be sure, they can get cancer malignancy, but the danger is really low. In the same way, guys can develop breast cancer, however, we do not promote mammography as a method to combat breast cancer in guys.
This message is very important to me as a black board-certified skin doctor and health services researcher at Dell Medical School at the University of Texas at Austin, where I am the director of the pigmented sore clinic. In this capacity, I look after clients at high risk for melanoma.
Cancer malignancy in black individuals is not associated with UV exposure
In the U.S., melanoma is 30 times more common among white people than black individuals.
In black individuals, cancer malignancy usually establishes in parts of the body that are not exposed to the sun, such as the palms of the hands and soles of the feet. These cancers are called “acral melanomas,” and sunscreen will not do anything to reduce the danger of these cancers.
When was the last time you had a sunburn on the soles or palms? Even amongst white people, there is no relationship between sun exposure and the risk of acral cancer malignancies. Notoriously, Bob Marley died from an acral cancer malignancy on his big toe, however sun block would not have assisted.
The unusual type of skin cancer that killed Bob Marley is believed to be triggered by an injury or trauma.
Two years ago my research group carried out a systematic evaluation in which we analyzed all of the published medical literature associated to UV exposure and melanoma in individuals of color. This includes those of African, Asian, Pacific Islander, Indigenous, and Hispanic descent. Of the 13 research studies that met our criteria for addition, 11 revealed no association between UV exposure and cancer malignancy.
Amongst the 2 research studies that showed an association, one study revealed a positive association in between melanoma and UV direct exposure in black guys. That same study likewise analyzed UV direct exposure and cancer malignancy in other groups, consisting of black women, white guys and ladies, and Hispanic guys and women.
The other study showing an association between UV and melanoma was among Hispanic men in Chile based upon latitude within the country. A significant caveat to this study is that the city with the greatest number of melanomas is likewise house to a large population of Chileans of Croatian descent, who would not be considered people of color.
None of these research studies determined melanin concentrations of people, so it is not possible to understand whether in theory lighter-skinned people of color may be at risk for UV-associated melanoma. Even in light-skinned East Asian individuals, there is no evidence that UV direct exposure is linked to melanoma.
The bottom line is that the link in between UV exposure and cancer malignancy in individuals of color has been studied often times over and has yielded little to no evidence of a connection.
Darker skin supplies more security from damage by the ultraviolet rays of the sun.
Racial disparities in melanoma results are not associated with UV exposure
Numerous skin specialists frequently point out that black patients tend to reveal up to the medical professional with later-stage melanoma, which holds true. This is an issue of gain access to and awareness and has absolutely nothing to do with sunscreen application or security from the sun. Black individuals should know developments on their skin and seek medical attention if they have any changing, bleeding, or otherwise concerning spots, particularly on the hands and feet.
Nevertheless, the concept that routine application of daily sun block will decrease an already exceptionally rare incident is ridiculous.
UV radiation does affect dark skin and can trigger DNA damage; nevertheless, the damage is seven to eight times lower than the damage done to white skin, offered the natural sun-protective result of increased melanin in darker skin.
To be clear, using routine sun block may aid with lowering other results of the suns rays such as sunburns, freckling, wrinkling, and photoaging, which are all positive. For the typical black individual, sun block is unlikely to lower their low danger of melanoma any further.
If sun block were important in the prevention of melanoma in dark-skinned clients, then why have we never ever heard of an epidemic of cancer malignancy in sub-Saharan Africa, an area with intense sun, a great deal of black people, and little sun block?
In particular subpopulations of black people, such as those with conditions causing sun sensitivity, or patients with albinism– a condition in which people produce little or no melanin– or those with reduced body immune systems, sun block use might minimize the danger of cancer malignancy. However if you do not fall under one of these classifications, any significant threat decrease from the application of sun block is unlikely.
One-size-fits-all public health messaging misses out on the mark
Many dermatology and skin cancer-focused organizations– including a few of which I belong to– promote the public health message of sun block use to lower cancer malignancy threat among black clients. There exists no study that demonstrates sun block decreases skin cancer danger in black individuals.
This issue of routine sun block usage in black individuals was made even more pressing after the release of 2 current studies on sun block absorption in the Journal of the American Medical Association. This study revealed that substantial amounts of certain chemical sun block components can get in the blood when used under maximal conditions, with unknown effects on human health.
To me, the most shocking part of the studies were that most of the individuals were black, the group least most likely to derive any significant involved health gain from sunscreen, while being exposed to potentially hazardous levels of chemicals.
As dermatologists and public health supporters, we can improve how we inform patients and the general public about melanoma prevention without promoting public health messages that are grounded in worry and lack proof. black people ought to be notified that they are at danger of establishing cancer malignancy, however that risk is low.
Any dark-skinned person who establishes a new, changing or symptomatic mole ought to see a doctor, especially if the mole is on the palms or soles. We dont know what the danger aspects are for melanoma in dark-skinned or black people, however they definitely are not UV rays.
Written by Adewole S. Adamson, Assistant Professor of Internal Medicine (Division of Dermatology), University of Texas at Austin.
This short article was first published in The Conversation.
