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Thursday, 4 June 2015

Statins and cancer stories - the stupidest thing you'll read this week.

If this isn't the stupidest thing I've read since that "high-protein diets kill mice fed lots of casein, ergo humans shouldn't eat paleo diet (which a priori eliminates casein)" story last week.

Statins 'could halve the risk of dying from cancer'


Apparently, people taking statins have much lower rates of cancer mortality. Cue more research and RCTs aimed at proving a new use for this class of drugs and sell even more prescriptions.

However, there are reasons why this claim (or carefully couched suggestion) amounts to quackery of the "false hope" sort. False hope for gullible GPs especially.

The studies did not show statins would prevent cancer. But they suggest taking them daily could save thousands of lives, by slowing the spread of diseases.
Doctors said it was not clear why they had such an effect, but the drugs reduce cholesterol, which is known to help the spread of disease.

Please do not bang your head quite so hard on your desk, no doctor recommends that (yet).

There are some basic things these "experts", and I use the inverted commas wisely, don't seem to know, or at least don't admit to knowing in a press release.

I summed up two of them in a letter to the Herald yesterday (unpublished so far).

Dear Sir/Ma'am,

According to a study reported in yesterday's Herald, people who take statin drugs are less likely to die from cancer. However, this effect has not been seen in 27 randomised, controlled trials. Statins are prescribed to people with high cholesterol. People with low cholesterol have an increased risk of cancer, and a greatly decreased likelihood of being prescribed statins. This might help to explain what is being presented as a possible protective effect of statins against cancer.


Yours sincerely,

George Henderson

References: (who includes references in letters to the Editor? I do. Maybe that's why they don't get published)

Serum cholesterol and cancer risk: an epidemiologic perspective.


http://www.ncbi.nlm.nih.gov/pubmed/1503812

Lack of Effect of Lowering LDL Cholesterol on Cancer: Meta-Analysis of Individual Data from 175,000 People in 27 Randomised Trials of Statin Therapy


http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029849

I wanted to save space to increase the odds of publication, so left out two other confounders;

1) People who take statins are goodie-goods. If the doctor tells them to take pills, they take them. If the doctor tells them to stop smoking, they stop. And so on. In fact doctors are less likely to prescribe statins to smokers.

2) Lots of people stop taking statins because of their side effects. Side effects - the inability to tolerate statins - could signify underlying diseases of ageing or nutritional deficiencies that also increase cancer risk or mortality.

If statins reduced cancer mortality an effect would be seen in RCTs. Statins cannot reduce cancer mortality by lowering LDL cholesterol, which is a protective risk factor for many common cancers, and for non-coronary mortality in ageing populations.

I'm not ruling out a cytotoxic effect of statins in certain cancers or a potentiating effect with specific cancer meds, but that's not what's being touted here, and were there a general effect of this sort with regard to more common cancers it would have shown in the RCTs.
.

4 comments:

Galina L. said...

Not long time ago Dr.Briffa had a post about the immunity/cholesterol connection http://www.drbriffa.com/2013/04/25/does-cholesterol-play-a-beneficial-role-in-immunity/. He was talking about the resistance to infections, but I guess , a better immunity allows a better protection from a cancer.

George Henderson said...

There are a couple of things going on - high LDL protects against liver infection with Hep C, which is a carcinogen, and probably plays a role in antiviral immunity more generally; many viruses are carcinogenic.
In the Japan study (last post) the highest LDL quartiles had zero incidence of serious liver disease. Cancer metastatis causes serious liver disease; is that then saying that high LDL prevents metastatis?
Also, low LDL is an effect of cancers, and low-grade systemic inflammations which can increase the risk of cancer, in ways independent of the protective effect of high LDL.

Steven Horvitz, D.O. said...

Well done!

karl said...

It looks like Statins actually raise BG - which is correlated with higher cancer rates. Which makes sense as many cancers don't do respiration instead glycolysis - higher BG would let the cancer out-grow the immune system.

I suspect Statins increase cancer rates in the long run.