The dangers of anecdotal evidence

Occasionally (too often) a newspaper publishes a story that is just downright irresponsible. This story from the Daily Express fits into this category.

‘I beat cancer by eating pineapples’ Brave woman, 31, shuns chemotherapy to self-medicate

Daily Express – 30/03/15

Any reader of this blog will understand that this is rubbish, but it’s worth looking at why anecdotal stories like this are useless as evidence for therapy.

Anecdotal evidence is essentially a story told by an individual or individuals. We are a story-telling species, and people generally find anecdotes highly compelling. That isn’t surprising really. In the past it was advantageous for us to err on the side of caution; it is usually harmless to mistakenly see two things as connected (my friend ate those berries and got sick), while not seeing things as connected could do you real damage (my friend ate those berries and got sick, but I’m sure I’ll be fine). As I discussed in a previous blog, we are very good at seeing patterns, whether they are real or imaginary. While that was a very useful strategy in the past, in the world of scientific medicine our trust of anecdotes is a damaging thing.

An example of this is the old story of “smoking can’t be dangerous; my granddad smoked 20 a day and lived to 92”. This is known as reporting bias. If the granddad had died earlier (or the woman in the article above had not recovered) the story would not have been repeated. We only hear about it the times when something appears to have worked, and not the times when the same thing didn’t work.

This is also similar to another form of bias that we are all prone to, confirmation bias. This is the well-known phenomenon that we are more likely to remember something if  it confirms an opinions we already have. So people who believe that chemotherapy is doing more damage than good are more likely to remember and repeat a story like this than another with a worse outcome.

Another major fault with anecdotal reports is that they are seen in isolation and not in a wider context. If someone is feeling ill they may try multiple things to see if they feel better. Most of the time they will get better all by themselves, but will give the credit to the last thing they tried. This is how most cold and flu “medicines” work, relying on the fact that people make this mistake. Just because one event happens before another (I took this product and then felt better), doesn’t mean that the first caused the second.

Modern medicine uses clinical trials as evidence for whether a therapy works or not. In many ways they are the exact opposite of anecdotes: they are blinded, so control for doctor and patient bias and the placebo effect; they expect random results like spontaneous regression and can see them in the wider context; and they typically have large numbers of people included (thousands) as opposed to tiny numbers of people in anecdotes.

Anecdotes

So back to this article. The author credits “cancer-zapping bromelain” for the regression of the cancer. In fact, there is very little suggestion that bromelain has anticancer activity. There are some studies on cells growing in a dish, but these are not reliable. It has been suggested to be effective in lessening the side-effects of chemotherapy, but there is no evidence for this (there was a registered clinical trial, but this has been completed and not reported results, suggesting a negative outcome).

The reality of this story is that people sometimes get better spontaneously. Even the deadliest cancers have spontaneous, unexplained regressions. A story like this can do no good, and has no place in the public sphere. Congrats Daily Express, you are just as bad as the Daily Mail.

10 thoughts on “The dangers of anecdotal evidence

  1. You must take into account that there are a lot of stories told that are bogus, especially if they make good press.

    Consider in an ER of a hospital a drug that may cause a bad reaction in a patient. Does the doctor say oh anecdotal evidence, trash this and continue to use the drug without critical thinking? Well you may say critical thinking may mean the doctor’s career is dead. My point is that you can’t just trash an individual’s evidence as trash just because there may be a lot of bad stories around.

    In actual fact I would say, of the real anecdotes that everyone, who is subjected to the same circumstances and is not aware of what they are up against may react in a very similar way. The problem is that not all of the conditions are visible and known.

    As for cancer, spontaneous remission doesn’t just happen for no reason. I have been able to effect spontaneous remission of cancer “on demand” and can now “stage-manage my biology to avoid developing cancer. It is possible for everyone and you don’t need medicines or special diets or anything else. Your body will do the job all you need is to see the big picture here: http://kyrani99godnscience.wordpresscom/contents-page/
    Kyrani

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    • I’m afraid you miss the point Kyrani. In your example, the problem isn’t the doctor responding to what he sees. It is the doctor then refusing to prescribe the drug on the basis of one patient having a side effect, while ignoring al the other patients who haven’t had side effects.

      As regards to the end of your comment, that is obviously rubbish.

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      • It is not about one patient having some side effect nor that the doctor refuses to prescribe on the basis of one patient. It is a question of turning your head away form the one or two or 50 or 50,000 etc because it puts a doctor’s career in jeopardy. It is human rights groups and related medical groups that look into this problem when it should be a register kept by doctors and trying to identify the reasons for the side effects. And that is to say nothing about regulatory bodies approving drugs that are harmful and allowing them on the market and countless cases of “one offs” are ignored until they reach the tens and hundreds of thousands.

        As for the rest of my comment that you are calling rubbish is based on 8 cancer episodes. The first one was spontaneous remission from stage 4 ovarian cancer that the doctors said inoperable and incurable and we can’t do anything. The second one was also a spontaneous remission but happened after I resolved some issues with people who wanted to do me harm. The rest I deliberately effected spontaneous remission after I used Vipassana or insight meditation to investigate another ovarian cancer. I let it spread to the bowel and grow to the size of a golf ball. My findings allowed me to effect remission deliberately.

        What is truly rubbish is the official medical story, that is that damage to the genome causes rogue cell to survive, grow out of control, metastasize and “colonize other organs and sites in the body”. It is BS. And the reason why it is rubbish is because cancer cells are extremely sophisticated cells, even superior to immune system cells in their capabilities. How do you create such superiority from damage? It is as good as saying if you put a virus into you car’s dedicated PC it will turn into a teleport transporter! The truth is that the body is purpose-driven and not a machine. The changes to the genome are epigenetic and deliberately and intelligently instigated for a perceived purpose but unfortunately an erroneous perception. And such changes are fully reversible when the patient understands what they are up against AND they are reversed by the body for FREE! Therein lies the problem for the medical industry. . When the truth be known two things are realized:
        1. cancer is a paper tiger, and
        2. our bodies are capable of phenominal intelligence, repair and regrowth and regeneration, well beyond anything imaginable.

        Kyrani.

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      • Wow, where to start?

        Your first paragraph is simply wrong. A register IS kept by doctors. Side-effects are logged and studied, and if a problem arises, then the drug is pulled. There is even a Wikipedia page listing all the significant drugs that have been withdrawn from the market since the 1960s!

        Your second paragraph is not only rubbish, but it is dangerous rubbish. You obviously went through an awful time (I can’t imagine how tough it must have been), but your regression is not proof that you can now cure cancer. Survival from cancer has doubled in the last 3 decades, not because people can now spontaneously cure themselves, but because surgery, radiotherapy and chemotherapy have become better and better. The numbers are clear.

        Finally, your knowledge of genetics and epigenetics is very flawed. I assume you don’t believe in evolution, as “damage” has resulted in the creation of all the species on the world from single celled organisms?

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      • “In the US the Food and Drug Administration runs a scheme called the Adverse Event Reporting System (AERS) where doctors can report side effects BUT the scheme is voluntary.”
        http://www.medicalnewstoday.com/articles/257631.php
        Australia and other countries do the same.

        And far from responsibility how about this
        http://www.abc.net.au/news/2013-11-27/growing-concerns-over-side-effects-of-seroquel/5120554
        This is some greedy doctors being precription happy and turn a blind eye to the side effects! But of course they get kickbacks from the pharmaceutical companies.

        Apart from my own experiences, I have known many other people saying that telling your doctor about side effects often gets the reaction of the doctor basically not wanting to know, shows signs of irritation and looks at their watch to try and give the message that the visit is taking too long.

        And then there is this evidence. . http://www.dailymail.co.uk/news/article-2954956/Statins-expert-drugs-effects-microscope-Professor-study-thousands-patient-records-discover-suffered-issues.html
        Why is a professor studying cases to discover side effects if the doctors have put them on record? The reason is the register’s a sham.

        You say “Survival from cancer has doubled in the last 3 decades”
        According to an oncology journal, the overall five-year cure rate of oncologists, on newly diagnosed cancer patients, is 3% (Clinical Oncology (2004) 16: 549-560).This means that in five years after diagnosis, 97% of the cancer patients of the mainstream medical community are dead. This is better than 50years ago BUT let’s also consider that 50 years ago the incidence was only 1 in 5, now it’s 1 in 3.

        The big problem is that everyone is looking for the most profitable cancer treatments ONLY. The pharmaceutical industry has the most profitable cancer treatments, which they are claiming are move effective today than ever before but their definition of cure is “live another five year and many with more problems than before diagnosis!

        Since my first episode of cancer it is now 22years! And since the last episode it over 5 years! And that is because I have understood the foul game play. You want to say my success is dangerous rubbish. It is not rubbish but it is dangerous.. to the cancer industry because people can get well by themselves. And those humane people with cancer reading my blogs and listening to the videos I am making, can and will get well using my methods. The proof of the pudding is in the eating.

        What is dangerous in my book is that many high profile people have sold out to the pharmaceutical companies, included are the media (who are financially supported by big pharma), the movie companies, governments, institutions such as the American Cancer Society, the Susan G. Komen Foundation etc., a country’s medical boards, Medical Associations, the health insurance companies, etc. etc. etc.This means there are no independent people in important institutions to give a critical view.

        Miscopying is only a fantasy story. Researcher trying to prove Darwin’s Evolutinary Theory using genetic mistakes have NEVER come up with anything useful arising from even one miscopied gene let alone a galaxy of stars full. Cancer cells have around 50,000 changes to the genome. You reckon they are mistakes. And given that genes code for proteins that fit together with other molecules like lock and key! WOW. Man they are polypotent stem cells that convert themselves to cancer stem cells. Even the supposed “ordinary cancer cells” are stem cells. When researchers have killed off all the recognizable cancer stem cells the ordinary ones convert themselves to new cancer stem cells. You reckon an evolutionary quick step dance and bingo there they are many new mistakes. Please!

        You assume right that I don’t buy Darwin’s Theory. To have evolved by naturally selected random changes, is not only improbable, given the way that life is organized, but impossible because it would need more billions of years than the universe is old (supposedly old because I don’t buy the expanding universe junk either).

        I don’t know how life began but it shows signs of design, intelligent design. Genetics is an algorithm, which expresses itself in many forms.
        Kyrani

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      • The scheme is voluntary but very effective. You can find the monthly newsletter for drug safety updates here (https://www.gov.uk/drug-safety-update), which gives an idea how active the reporting system is. Out of interest, do you claim that all doctors are ignoring side effects? That a majority of them are? Or that some of them are?

        The fact that side effects are studies is an example of science working, not failing. Why do you think the Prof Collins is studying Statins? It is because of reported side-effects. (It’s worth pointing out that Statins have had an overwhelmingly positive effect on human health, and that this controversy isn’t widely accepted in the medical community yet due to lack of evidence).

        Regarding cancer survival, I’m afraid you have your numbers wrong. 46% of men and 54% of women in the UK will survive their cancer for 10 years or more (http://www.cancerresearchuk.org/health-professional/cancer-statistics/survival/all-cancers-combined). The article you cite references only¬ the benefit attributed to cytotoxic chemotherapy. The abstract to that paper even states “the 5-year relative survival rate for cancer in Australia is now over 60%”.

        Your point about profit is also wrong. Profit isn’t the driving force behind most cancer research. Pharmaceutical companies rely on a profit driven model (which is a problem, but very difficult to avoid), but the majority of cancer researchers are academic or charity funded. Our current cancer strategies do cause side-effects, but they are more effective than ever, and countless people are alive now who otherwise wouldn’t be.

        Out of interest, all of these hundreds of thousands (probably millions) of people who have sold out to “Big Pharma”, is there not a single one with a conscience? No whistle blowers? Are they all psychopaths who don’t care about human suffering? I work in cancer research. Am I in the pay of big pharma to spend my summer evenings writing a blog and arguing with people online (I can assure you I’m not!)?

        As I said in my last reply, your knowledge of genetics is lacking. A cancer cell has far more than 50,000 changes. When a cell divides, roughly 120,000 mistakes are introduced into the DNA (http://www.nature.com/scitable/topicpage/dna-replication-and-causes-of-mutation-409). However, almost all of these are silent (mutations that don’t affect the cell). To put that number into perspective, this means that the cell has an error rate of 0.00004%, which is incredibly low and speaks to how amazing the human body is. When you consider that there are 37,000,000,000,000 (37 trillion) cells in an adult, even with an error rate that low, it is remarkable how little cancer we get. Regarding your comments on stem cells, a there was recently a beautiful paper published that showed how intestinal stem cells can become cancerous with a single mutation (http://www.ncbi.nlm.nih.gov/pubmed/24264992). They don’t “convert themselves to cancer stem cells”, they get an oncogenic mutation and that gives them an advantage over the other stem cells. That lets them live far longer, allowing extra time for additional mutations. Cancer stem cells are a very well studied and understood field now.

        Finally, your denial of evolution relies on a false premise. Rather than it being improbably, given the random error rate in replication and the pressure of natural selection, evolution is absolutely inevitable. The theory of evolution through natural selection is among the most tested theories in the history of science, and it has come through with flying colours. To deny it is to ignore or misunderstand the evidence.

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    • Sorry, the blog is an evening thing for me, and I’ve been busy over the last few days.

      Although, I wish I was supported by big pharma. I could do with the cash. Unfortunately I have morals. Also, a quick read of my recent posts would show you that I am no fan of the pharmaceutical industry.

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