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Ade Adamson, MD @AdeAdamson
, 21 tweets, 5 min read Read on Twitter
I’m glad that this article was written, it makes a LOT of great points about sun exposure and melanoma, but I think a few things need further discussion.

My final #tweetorial of 2018! 👇🏾👇🏾👇🏾
In order to appreciate the complexity of this relationship (i.e. sun exposure and melanoma), one must remember that measuring sun exposure over time is HARD.
The sun is all around us making it difficult to measure exposure levels and thus draw conclusions with absolute certainty.
Aside: It’s a lot easier to measure smoking exposure, for example, because it’s an exposure one actively engages in and more easily measured/documented.
Notably, given that melanoma is not an extremely common cancer, most studies evaluating the sun/melanoma relationship are case-control, which are prone to recall bias for sun exposure.
This means that those that get diagnosed with melanoma have a higher likelihood of reporting that they have been heavily exposed to the sun.
This makes sun exposure a self-fulfilling risk factor, as discussed by Gil Welch and @OtisBrawley in their annals paper:…
Also, as pointed out by @peterubel those that have high sun exposure are more likely to seek a dermatologist, and have lesions biopsied that could be early melanomas (some destined to harm, others that would never have progressed)
However, DON’T confuse melanoma DIAGNOSIS with melanoma DEATH, these are related, but very much separate. This is CRUCIAL to understand.
In the US over 90,000 melanomas are diagnosed and over 9,000 die from the disease.
It is true that the sun can increase risk of melanoma DIAGNOSIS, but at the same appear to be “protective” against death from melanoma. It’s possible that a proportion of lesions that are diagnosed as melanomas in sun worshipers are more likely represent non-lethal disease.
Unfortunately, we don’t have the tools yet to discern which melanomas are destined to cause death and those that won’t progress.
Where I differ from the forbes article is the implication that sun exposure INCREASES the risk of DEATH from melanoma.
To my knowledge most population-based studies looking at sun exposure and MORTALITY show that either it has no effect on melanoma survival or it has a positive effect.
In this 2005 study, sun exposure was associated with increased survival from melanoma.
In this 2014 study, authors concluded that there is little to no effect of sun exposure on melanoma
In a prospective 20-year follow-up of the Melanoma in Southern Sweden (MISS) cohort of nearly 30,000 women, more sun exposure was associated with HIGHER life expectancy. 🧐
I think that the sun certainly increases your risk of getting a diagnosis of melanoma, but I still think there is much uncertainty whether or not it increases your chance of DEATH from melanoma.
These are very hard things to hold together for many people and this is a hugely controversial subject in dermatology. However, I think it’s important that we be honest about the current evidence.
Before folks hop in my mentions with nonsense, I still think sun protection is important.
Happy new year!!!
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