Hacker News Reader

Comment by Fire-Dragon-DoL | Hacker News Reader

Stupid question since I don't live in Australia. Is the skin cancer a consequence of the sunburn or do they get it without sunburn?

View on HN

I can't speak for Australia, but in general you definitely don't need to burn for increased cancer risk - a clear example of that is the fact that artificial UV tanning beds lead to significantly increased rates of cancer despite the fact that they're used in such a way that you tan without going far enough to burn.

Although we often think of burning as bad and tanning as good, tanning is nonetheless still actually a symptom of your skin being damaged by the sun - it's just a symptom that looks better than burned skin, to the point that many people think it looks nice enough to be worth the cancer risk (and/or don't understand the risk when they decide to tan).

You don't need to get sun burns to get skin cancer, but there is of course a strong correlation.

Australia does have the highest records of skin cancer diagnosis per capita though, and it has for some time. [1] The reason for it is for a few reasons.

A prevalance of outdoors focused lifestyles, exasperated by a higher amount of UV penetration to the ground due to proximity to the equator, and a much smaller/thinner O-zone layer than anywhere else in the world. This applies to both Australia and New Zealand btw.

Both due to the location, and man made causes (e.g., CFC's) [2]. Though fortunately, the O-zone layer is getting much better and quite quickly. The article I linked states the ozone layer will be at pre-1980 levels by 2050. Taking this at face value without much scrutiny though.

Australian's statistically have fairer skin. I'm half Cypriot by mother's, Norweigan. I did not get my fathers complexion ;-).

Throw in the sheer number of people who travel here from places where the ozone is much stronger/better, means people enjoying our lifestyle without the same level of protection warranted. I thiink this risk is overstated though, I made the mistake of not using enough sunscrean or clothing once, and got the most hellish skin burn. You only ever make that mistake once.

[1] https://biologyinsights.com/which-country-has-the-highest-ra... [2] https://cyclimate.com/article/does-australia-have-an-ozone-l...

You absolutely don't need sunburns to get skin cancer from sun exposure. In fact, any skin tanning happens as a reaction to oxidative stress and DNA damage/repair! Of course, the amount of tanning is dependent on genetics, some people hardly tan at all. But if your skin gets darker due to sun exposure, it is evidence of radiation induced DNA damage. Sunburns may contribute a bit more, but it's the overall lifetime exposure to UV radiation, which is the main risk factor (accumulated DNA damage).

However, melanoma, the most dangerous form of skin cancer, also sometimes develops in areas hardly ever exposed to UV light. Like inside eyes, or in the groin. Melanocytes originate from the neural crest and are spread all over the body. Due to their ontogenetic origin (loose tissue association), melanoma is always bad news, while other forms of skin cancer hardly ever metastasize.

https://en.wikipedia.org/wiki/Sun_tanning

https://en.wikipedia.org/wiki/Melanocyte

https://en.wikipedia.org/wiki/Neural_crest

I see, so the goal is to not get tanning at all, essentially

You shouldn't seek any tanning, yes. Sun light exposure is also beneficial, as you may know. Mood, circadian rhythm, vitamin D, ... . Also, intense exposure on skin, which hasn't ramped up defenses is worse than on "trained" skin.

Mostly concerned for my kids (although we are not in Australia, we are in Canada, west coast), we don't get sunburn and we avoid sun from 11 until 3 PM (if we do, we put sunscreen on), but usually we don't put sunscreen on after 3 PM, so I was re-evaluating my practice, since my daughter does get tanned over summer by simply playing at the playground at 10 AM in the summer

The amount of tanning isn't really an indicator, because it depends on the genetics how much melanin is in the skin to begin with and how much is produced as reaction to damage. I think the most important thing to keep in mind is not trying to get tanned intentionally, like the generations before us. IIRC, in about 70% of melanoma cancers you have a good chance of catching it early and be done with it. Once it metastasizes melanoma got a very bad prognosis. So, as adult, it's also important to frequently screen for it. Other skin cancers are usually not existentially threatening, but can fuck you up aesthetically, e.g. removal sacrificing chunks of your nose.

Personally, I use the UV index charts and avoid extremes, midday sun completely. I put on 50 SPF to my face and neck every time I leave the house. It's just routine. In winter I may skip it, because good sun screen is fucking expensive. Not so much about skin cancer, but rather skin aging. The face is always exposed. I am trying to get a little intentional sun exposure in spring after dark winter, slowly preparing my skin for summer and improving mood. However, I tan easily. If I had the skin type I, I would avoid the sun much more.

Did you notice how many people these days look younger? Even in their 30s? I think that's no smoking, intentional nutrition, exercise and sun screen (from childhood on).

Reply on news.ycombinator.com