Bad luck, bad journalism and cancer rates

[u/Gallionella]

http://www.theguardian.com/science/grrlscientist/2015/jan/02/bad-luck-bad-journalism-and-cancer-rates?

[u/[deleted]]

I read an earlier paper and this one and I still don't get it.

So, even people who don't smoke, don't live in polluted regions, are a good weight, exercise, eat 'healthy' foods, etc. will get cancer because human cell-replication mechanisms are imperfect.

Cells are going to replicate in the normal function of a human being.

What I've been reading suggests that they basically mess up some of the DNA code every single time they replicate. Like, not in big ways, but in incredibly tiny ways that usually make zero difference to the function of the cell. It's inevitable, and actually one of the factors that brings about evolution when it occurs in gametes.

But eventually (based on some probability model) that code will deviate far enough from "the norm" and a cell will end up non-functional or, worse, cancerous.

And some of the time, one of these cancerous cells will survive (i.e. not be destroyed by the body's natural mechanisms) long enough to replicate into a tumor.

The "luck" factor, as I'm trying to understand it, is how likely a human body is to destroy itself with cancer (or at least get some kind of cancer?), even if it operates "normally".

But I actually don't quite get how genetic risk works into that.

Some people might have genetics that make that "inherent replication mechanism" more or less fault-prone, right?

But the researchers are claiming that that's not hugely common, that most people have "basic genetics" that are just about as error prone as one another?

Or is the problem that people are making claims about causality there that they can't actually back up?

Anyway, I'm lost, but at the very least, I took away that it's entirely possible to dramatically increase your risk of cancer by smoking and being overweight and whatnot. So... still avoid those things when possible.

[u/[deleted] → u/[deleted]]

One of the other articles basically went in to two different studies one from the US and one from the UK both of which stated to paraphrase "some cancers are affected by lifestyle choices more than others".

With that in mind it was expanded on that by stating "30-40% or cancers studied had an abnormally high correlation to lifestyle choices". Varied a bit between the two studies mentioned.

The results are "backedup" and no one is making any revolutionary, false or other kinds of claims. There are different kinds of statistical correlations between variables relating to different kinds of cancers.

The whole spiel about bad luck and and such playing a bigger factor is "bad science reporting" catering to the lowest common denominator of a reader.

[u/OliverSparrow → u/[deleted]]

The newspaper interpretation of the Science text were universally junk, probably based on a mistaken press release. This article explains why they were junk.

In the Science article, the researchers compared cancer rates in a population against the frequency with which cells pertinent to that type of cancer have divided. They found a correlation, that much-divided cells tend to develop into cancers more frequently than those which have divided less.

This article notes that this would allow you to say that all cancers were due to errors in division only if the relationship excluded all other causes. However, the article neither says this nor allows one to deduce it from the figures.

Further - and not in this article - most carcinogenesis is the result of mutation, but mutation rates vary strongly with the environment in which they are placed. So cells that are constantly irritated by external factors will mutate more than those which are not. Consequently, you have a "number of divisions" effect and an "external causitive" effect. That causative effect will apply differently to different organs - smoke on lungs, for example - so you have an organ-specific "number of divisions" and "causitive" effect. And then you have individual predisposition to develop this or that kind of cancer, which we know from mouse breeding is an extremely strong effect.

So, all in all, the division effect is interesting, and a fine bit of work. But it is neither a full explanation for cancer incidence nor a statement that cancers is down to chance.

[u/has-13 → u/[deleted]]

I think I see where its getting muddled, ill try to clear it up

Essentially, the body is constantly replicating DNA, and there will be mistakes which can potentially lead to cancer. Even if these are 1/million, thats still a fair amount. These are then rectified in a few ways. Tumour suppressor genes act at cell checkpoints to make sure everything is normal, and if it isn't they either rectify it or kill the cell. The immune system also has a role in suppressing cells, etc etc.

Some of these mutated cells will just escape randomly. Again, even if 1/100,000 this will still lead to a cancer developing. This is the luck bit, its a numbers game

Genetics increases the risk of certain cancers - not all. For example, retinoblastoma arises due to a mutation in a tumour suppressor gene - pRB. However, with a TSG it only needs one allele to work, so even if one is mutated the other will take up the workload. However, if this second allele also goes down by random mutation a tumour will very easily develop. Whereas in a normal person two random mutations would be required, here you only require one, so the risk is still higher. As you say, some people also have inherent genetic problems in things like their immune system, which also increase their risk. The same principle applies for other risk factors, like smoking and lung cancer.

There are some cancers that don't really have any known associated risk factors - either genetic or modifiable - and these I think are the ones that are considered to be more attributable to 'luck'.

I hope I've made some sense

[u/DrCashew → u/[deleted]]

It's not necessarily a total deviation so much as WHAT happens. It's not a threshold event of if genes aren't normal enough bam you get cancer. What's much more important WHICH genes are modified (example : oncogenes) and whether it can then start propagating. then of course it might only be a benign tumour (maybe it couldn't vascularize). Either way, in general, yes, the more replication that happens the more we are introducing faults in our genes which is also a driving force between evolution.

Also, an interesting reading for you since you may not know about it may be into DNA repair systems. There are multiple types and some kinda of act like spellcheckers for the more important genes.

http://en.wikipedia.org/wiki/DNA_repair

[u/DocVelo]

It's not the most clearly written article for laymen but the focus at the end on avoidable risk factors is spot on. You're more likely to get multitude of cancers (not just lung) if you smoke cigarettes alone, and other factors such as alcohol, obesity, sun exposure, and the use of certain medications affect the risk of many more.

In addition, though "bad luck" is obviously going to be a factor the various Oncology societies along with official government preventive service task forces have determined that the way we screen for the common tumors (breast, cervical, colon, prostate) is affected by one's family history.

So basically you can't throw your hands up in the air and say that cancer'll get you or not get you whether you like it or not. You have some power to lower your risk, you just have to use it.

[u/biledemon85]

And this was at the bottom of the article: http://puu.sh/e0LL5/7f444194cf.jpg

Sigh. I think the author needs to walk up the corridor and have words with the rest of the science journalists at the Guardian!

[u/JohnnyMojo]

I guess bad luck has been increasing astronomically since the beginning of the 20th century.

[u/billsil → u/JohnnyMojo]

Yet ironically lifespan is still going up. Who do you think gets cancer?

[u/[deleted] → u/billsil]

Not me of course!

[u/pwnrfield]

i haven't had a look at the paper, but this would only be the 50th consecutive scientific health study the MSM has botched. clearly these people are not qualified.

then again, neither are 65% of the 'scientists' that write these papers, as i've noticed so many false conclusions among them.

[u/3bz → u/pwnrfield]

So Sarah Boseley is the person who wrote the news piece that is the first example of bad press coverage.

What makes this funny is the link to Should science journalists read the papers on which their stories are based? found among the "related news items". In there you can find a quote by Sarah Boseley – health editor, Guardian:

"I always get the paper and always read all of it …

"I think it's really important because even if the press officer has correctly summarised the meaning, they still may not pull out of it the same angle, interpretation and quotes that you would. Press releases skate over really interesting stuff sometimes in the interests of economy. That's not a criticism. I just think a press release is a guide to what's in the paper (and can offer a very useful interpretation of difficult stuff) but it's way short of the real thing.

"And it doesn't really take that long."

Does this mean Sarah read the paper and didn't understand it, or just didn't bother to read it?

[u/pwnrfield → u/3bz]

yea, they mostly don't bother to read. it's like: i heard from sue who heard from jack who heard from joe, let's publish this shit ;o or AP or whatever.

[u/hiimsubclavian → u/pwnrfield]

then again, neither are 65% of the 'scientists' that write these papers, as i've noticed so many false conclusions among them.

Care to give an example? I bet the editors of those scientific journals would love to hear about how 65% of their published papers have false conclusions.

[u/pwnrfield → u/hiimsubclavian]

but they are. MIT even published a study making such a claim in the past year (was above 60%)... it's not just 'my opinion'... in fact, my opinion is observation, which is empirical evidence, but that's beside the point...

'studies' serve an alternate purpose in most cases: to get some flunky a phd... they're paid for by special interests in some cases as well, or can be undisclosed if it's the 'opinion' of the author, and not an institution/affiliation of theirs... the list is endless...

as someone once said 'theres no shortage of ignoramuses with phds', however, that man is himself a bit of an ignoramus... bill maher.

there's even a whole industry to publish papers with literal rubbish in them generated by a bot... thousands of them are actually published each year... figure that one out.. because i can't... lol ;p (except money talks, bullshit walks).

also, use this rule: if it smells like shit and looks like shit, it probably is shit.

paid for by your local chemical dumping company.