Don’t believe the hype – 10 persistent cancer myths debunked
Category: Science blog March 24, 2014
The problem is that much of the information out there is at best inaccurate, or at worst dangerously misleading. There are plenty of evidence-based, easy to understand pages about cancer, but there are just as many, if not more, pages spreading myths.
And it can be hard to distinguish fact from fiction, as much of the inaccurate information looks and sounds perfectly plausible. But if you scratch the surface and look at the evidence, many continually perpetuated ‘truths’ become unstuck.
In this post, we want to set the record straight on 10 cancer myths we regularly encounter. Driven by the evidence, not by rhetoric or anecdote, we describe what the reality of research actually shows to be true.
- Myth 1: Cancer is a man-made, modern disease
- Myth 2: Superfoods prevent cancer
- Myth 3: ‘Acidic’ diets cause cancer
- Myth 4: Cancer has a sweet tooth
- Myth 5: Cancer is a fungus – and sodium bicarbonate is the cure
- Myth 6: There’s a miracle cancer cure…
- Myth 7: …And Big Pharma are suppressing it
- Myth 8: Cancer treatment kills more than it cures
- Myth 9: We’ve made no progress in fighting cancer
- Myth 10: Sharks don’t get cancer
Myth 1: Cancer is a man-made, modern disease
While it’s certainly true that global lifestyle-related diseases like cancer are on the rise, the biggest risk factor for cancer is age.
The simple fact is that more people are living long enough to develop cancer because of our success in tackling infectious diseases and other historical causes of death such as malnutrition. It’s perfectly normal for DNA damage in our cells to build up as we age, and such damage can lead to cancer developing.
We’re also now able to diagnose cancers more accurately, thanks to advances in screening, imaging and pathology.
Yes, lifestyle, diet and other things like air pollution collectively have a huge impact on our risk of cancer – smoking for instance is behind a quarter of all cancer deaths in the UK – but that’s not the same as saying it’s entirely a modern, man-made disease. There are plenty of natural causes of cancer – for example, one in six worldwide cancers is caused by viruses and bacteria.
Myth 2: Superfoods prevent cancer
Blueberries, beetroot, broccoli, garlic, green tea… the list goes on. Despite thousands of websites claiming otherwise, there’s no such thing as a ‘superfood’. It’s a marketing term used to sell products and has no scientific basis.
That’s not to say you shouldn’t think about what you eat. Some foods are clearly healthier than others. The odd blueberry or mug of green tea certainly could be part of a healthy, balanced diet. Stocking up on fruits and veg is a great idea, and eating a range of different veg is helpful too, but the specific vegetables you choose doesn’t really matter.Our bodies are complex and cancer is too, so it’s gross oversimplification to say that any one food, on its own, could have a major influence over your chance of developing cancer.
We’ve also written extensively on the scientific evidence about anti-oxidants and cancer in these posts – part one, part two and part three. [Added 28/03/14 KA]
The steady accumulation of evidence over several decades points to a simple, but not very newsworthy fact that the best way to reduce your risk of cancer is by a series of long-term healthy behaviours such as not smoking, keeping active, keeping a healthy body weight and cutting back on alcohol.
Myth 3: ‘Acidic’ diets cause cancer
This is biological nonsense. True, cancer cells can’t live in an overly alkaline environment, but neither can any of the other cells in your body.
Blood is usually slightly alkaline. This is tightly regulated by the kidneys within a very narrow and perfectly healthy range. It can’t be changed for any meaningful amount of time by what you eat, and any extra acid or alkali is simply peed out in urine.
To maintain the correct balance within the body, your urine can and does change pH, depending on what you’ve eaten (explained in detail in this post). This can be seen by testing urine pH (acidity) after eating different foods and is the basis of the mistaken belief that diet can “make the body alkaline”. But that’s all you’re changing, and anyone who claims otherwise simply doesn’t understand how the body works. [Edited for clarity and extra links, KA 08/08/14]
While eating lots of green veg is certainly healthy, that’s not because of any effect on how acid or alkaline your body is.There is something called acidosis. This is a physiological condition that happens when your kidneys and lungs can’t keep your body’s pH (a measure of acidity) in balance. It is often the result of serious illness or poisoning. It can be life-threatening and needs urgent medical attention, but it’s not down to overly acidic diets.
We know that the immediate environment around cancer cells (the microenvironment) can become acidic. This is due to differences in the way that tumours create energy and use oxygen compared with healthy tissue. Researchers are working hard to understand how this happens, in order to develop more effective cancer treatments.
But there’s no good evidence to prove that diet can manipulate whole body pH, or that it has an impact on cancer.
Myth 4: Cancer has a sweet tooth
This is an unhelpful oversimplification of a highly complex area that we’re only just starting to understand.
‘Sugar’ is a catch-all term. It refers to a range of molecules including simple sugars found in plants, glucose and fructose. The white stuff in the bowl on your table is called sucrose and is made from glucose and fructose stuck together. All sugars are carbohydrates, commonly known as carbs – molecules made from carbon, hydrogen and oxygen.
Carbs – whether from cake or a carrot – get broken down in our digestive system to release glucose and fructose. These get absorbed into the bloodstream to provide energy for us to live.
All our cells, cancerous or not, use glucose for energy. Because cancer cells are usually growing very fast compared with healthy cells, they have a particularly high demand for this fuel. There’s also evidence that they use glucose and produce energy in a different way from healthy cells.
Researchers are working to understand the differences in energy usage in cancers compared with healthy cells, and trying to exploit them to develop better treatments (including the interesting but far from proven drug DCA).
But all this doesn’t mean that sugar from cakes, sweets and other sugary foods specifically feeds cancer cells, as opposed to any other type of carbohydrate. Our body doesn’t pick and choose which cells get what fuel. It converts pretty much all the carbs we eat to glucose, fructose and other simple sugars, and they get taken up by tissues when they need energy.
While it’s very sensible to limit sugary foods as part of an overall healthy diet and to avoid putting on weight, that’s a far cry from saying that sugary foods specifically feed cancer cells.
Both the ‘acidic diet’ and ‘sugar feeds cancer’ myths distort sensible dietary advice – of course, nobody is saying that eating a healthy diet doesn’t matter when it comes to cancer. You can read about the scientific evidence on diet and cancer on our website.
But dietary advice must be based on nutritional and scientific fact. When it comes to offering diet tips to reduce cancer risk, research shows that the same boring healthy eating advice still holds true. Fruit, vegetables, fibre, white meat and fish are good. Too much fat, salt, sugar, red or processed meat and alcohol are less so.
Also, this post, “What should you eat while you’re being treated for cancer“, is packed with links to evidence-based advice from our CancerHelp UK website. And this post, from the Junkfood Science blog, explores the science behind sugar and cancer in more detail.
[Edited to add more information and links KA 28/03/14]
Myth 5: Cancer is a fungus – and sodium bicarbonate is the cure
One obvious problem with this idea – apart from the fact that cancer cells are clearly not fungal in origin – is that cancer isn’t always white. Some tumours are. But some aren’t. Ask any pathologist or cancer surgeon, or have a look on Google Image search (but maybe not after lunch…).
Proponents of this theory say that cancer is caused by infection by the fungus candida, and that tumours are actually the body’s attempt at protecting itself from this infection.
But there’s no evidence to show that this is true.
Furthermore, plenty of perfectly healthy people can be infected with candida – it’s part of the very normal array of microbes that live in (and on) all of us. Usually our immune system keeps candida in check, but infections can get more serious in people with compromised immune systems, such as those who are HIV-positive.
The ‘simple solution’ is apparently to inject tumours with baking soda (sodium bicarbonate). This isn’t even the treatment used to treat proven fungal infections, let alone cancer. On the contrary, there’s good evidence that high doses of sodium bicarbonate can lead to serious – even fatal – consequences.
Some studies suggest that sodium bicarbonate can affect cancers transplanted into mice or cells grown in the lab, by neutralising the acidity in the microenvironment immediately around a tumour. And researchers in the US are running a small clinical trial investigating whether sodium bicarbonate capsules can help to reduce cancer pain and to find the maximum dose that can be tolerated, rather than testing whether it has any effect on tumours.
As far as we are aware, there have been no published clinical trials of sodium bicarbonate as a treatment for cancer.
It’s also worth pointing out that it’s not clear whether it’s possible to give doses of sodium bicarbonate that can achieve any kind of meaningful effect on cancer in humans, although it’s something that researchers are investigating.
Because the body strongly resists attempts to change its pH, usually by getting rid of bicarbonate through the kidneys, there’s a risk that doses large enough to significantly affect the pH around a tumour might cause a serious condition known as alkalosis.
One estimate suggests that a dose of around 12 grams of baking soda per day (based on a 65 kg adult) would only be able to counteract the acid produced by a tumour roughly one cubic millimetre in size. But doses of more than about 30 grams per day are likely to cause severe health problems – you do the maths.
Myth 6: There’s a miracle cancer cure…
But extraordinary claims require extraordinary evidence – YouTube videos and Facebook posts are emphatically not scientific evidence and aren’t the same as good-quality, peer-reviewed evidence.
In many cases it’s impossible to tell whether patients featured in such anecdotal sources have been ‘cured’ by any particular alternative treatment or not. We know nothing about their medical diagnosis, stage of disease or outlook, or even if they actually had cancer in the first place. For instance, we don’t know what other cancer treatments they had.
And we only hear about the success stories – what about the people who have tried it and have not survived? The dead can’t speak, and often people who make bold claims for ‘miracle’ cures only pick their best cases, without presenting the full picture.
This highlights the importance of publishing data from peer-reviewed, scientifically rigorous lab research and clinical trials. Firstly, because conducting proper clinical studies enables researchers to prove that a prospective cancer treatment is safe and effective. And secondly, because publishing these data allows doctors around the world to judge for themselves and use it for the benefit of their patients.
This is the standard to which all cancer treatments should be held.
That’s not to say the natural world isn’t a source of potential treatments, from aspirin (willow bark) to penicillin (mould). For example, the cancer drug taxol was first extracted from the bark and needles of the Pacific Yew tree.
But that’s a far cry from saying you should chew bark to combat a tumour. It’s an effective treatment because the active ingredient has been purified and tested in clinical trials. So we know that it’s safe and effective, and what dose to prescribe.
Of course people with cancer want to beat their disease by any means possible. And it’s completely understandable to be searching high and low for potential cures. But our advice is to be wary of anything labelled a ‘miracle cure’, especially if people are trying to sell it to you.
Wikipedia has this excellent list of ineffective cancer treatments that are often touted as miracle cures, which is worth a browse.
If you want to know about the scientific evidence about cannabis, cannabinoids and cancer – a topic we’re often asked about – please take a look at our extensive blog post on the subject, including information about the clinical trials we’re helping to fund.
And if you’ve seen links to article about scientists in Canada “curing cancer but nobody notices”, these refer to an interesting but currently unproven drug called DCA, which we’ve also written about before. [Added KA 28/03/14]
Myth 7: … and Big Pharma are suppressing it
Whatever the particular ‘cure’ being touted, the logic is usually the same: it’s readily available, cheap and can’t be patented, so the medical establishment is suppressing it in order to line its own pockets. But, as we’ve written before, there’s no conspiracy – sometimes it just doesn’t work.
There’s no doubt that the pharmaceutical industry has a number of issues with transparency and clinical trials that it needs to address (the book Bad Pharma by Ben Goldacre is a handy primer). We push regulators and pharmaceutical companies hard to make sure that effective drugs are made available at a fair price to the NHS – although it’s important to remember that developing and trialling new drugs costs a lot of money, which companies need to recoup.
Problems with conventional medicine don’t automatically prove that alternative ‘cures’ work. To use a metaphor, just because cars sometimes crash doesn’t mean that flying carpets are a viable transport option.
It simply doesn’t make sense that pharmaceutical companies would want to suppress a potential cure. Finding a highly effective therapy would guarantee huge worldwide sales.
And the argument that treatments can’t be patented doesn’t hold up. Pharma companies are not stupid, and they are quick to jump on promising avenues for effective therapies. There are always ways to repackage and patent molecules, which would give them a return on the investment required to develop and test them in clinical trials (a cost that can run into many millions) if the treatment turns out to work.
It’s also worth pointing out that charities such as Cancer Research UK and government-funded scientists are free to investigate promising treatments without a profit motive. And it’s hard to understand why NHS doctors – who often prescribe generic, off-patent drugs – wouldn’t use cheap treatments if they’d been shown to be effective in clinical trials.
For example, we’re funding large-scale trials of aspirin – a drug first made in 1897, and now one of the most widely-used off-patent drugs in the world. We’re researching whether it can prevent bowel cancer in people at high risk, reduce the side effects of chemotherapy, and even prevent cancer coming back and improve survival.
Finally, it’s worth remembering that we are all human – even politicians and Big Pharma executives – and cancer can affect anyone. People in pharmaceutical companies, governments, charities and the wider ‘medical establishment’ all can and do die of cancer too.
Here at Cancer Research UK we have seen loved ones and colleagues go through cancer. Many of them have survived. Many have not. To suggest that we are – collectively and individually – hiding ‘the cure’ is not only absurd, it’s offensive to the global community of dedicated scientists, to the staff and supporters of cancer research organisations such as Cancer Research UK and, most importantly, to cancer patients and their families.
Myth 8: Cancer treatment kills more than it cures
And sometimes, sadly, treatment doesn’t work. We know that it’s very difficult to treat late-stage cancer that has spread throughout the body, and while treatment can provide relief from symptoms and prolong life, it’s not going to be a cure for very advanced cancers.
Surgery is still the most effective treatment we have for cancer, provided it’s diagnosed early enough for an operation to be done. And radiotherapy helps cure more people than cancer drugs. Yet chemotherapy and other cancer drugs have a very important part to play in cancer treatment – in some cases helping to cure the disease, and in others helping to prolong survival.
The claims on the internet that chemotherapy is “only 3 per cent effective” are highly misleading and outdated, and are explored in more depth in these two posts from the Science Based Medicine blog.
We also wrote this post in response to concerns that chemotherapy might “encourage cancer”.
It important to point out that in an increasing number of cases, the drugs do work. For example, more than 96 per cent of all men are now cured of testicular cancer, compared to fewer than 70 per cent in the 1970s thanks in part to a drug we helped to develop called cisplatin. And three-quarters of children with cancer are now cured, compared with around a quarter in the late 1960s – most of them are alive today directly thanks to chemotherapy.
We know that we still have a long way to go until we have effective, kinder treatments for all types of cancer. And it’s important that doctors, patients and their families are realistic and honest about the best options for treatment, especially when cancer is very advanced.
It may be better to opt for treatment aimed at reducing pain and symptoms rather than attempting to cure the disease (palliative care). Balancing quality and quantity of life is always going to be an issue in cancer treatment, and it’s one that each patient must decide for themselves.
Myth 9: We’ve made no progress in fighting cancer
This article by our chief clinician, Professor Peter Johnson, outlines some of the key facts.
By definition, these figures relate to people treated at least 10 years ago. It’s likely that the patients being diagnosed and treated today have an even better chance of survival.
To see how the picture has changed, make yourself a cuppa and settle down to watch this hour-long documentary we helped to make – The Enemy Within: 50 years of fighting cancer. From the early days of chemotherapy in the 50s and 60s to the latest ‘smart’ drugs and pinpoint-accurate radiotherapy, it highlights how far we’ve come over the years.
There’s still a long way to go. There are some cancers where progress has been much slower – such as lung, brain, pancreatic and oesophageal cancers. And when you lose someone you love to cancer, it can feel as though no progress has been made at all.
That’s why we’re working so hard to beat cancer sooner, to make sure that nobody loses their life prematurely to the disease.
Myth 10: Sharks don’t get cancer
This excellent article goes into why the myth about the cancer-free shark has been so persistent.
Olly and Kat
Useful links
- CancerHelp UK – Alternative and complementary therapies
- NHS Behind The Headlines
- US National Cancer Institute – Alternative and complementary therapies
- Memorial Sloan Kettering Cancer Centre – Herbs, botanicals and other products
- American Cancer Society – Complementary and alternative therapies
- Science-based Medicine blog
- Wikipedia: list of ineffective cancer treatments
- Quackwatch – a special message to cancer patients
- ASCO Answers – Myths and Facts about Cancer (pdf)
No comments:
Post a Comment