Adam Smith

Science and Communications Officer, ANH-Intl

A new report in the British Journal of Cancer relies on bad science and incomplete data to perpetuate several mainstream cancer myths – while selling itself as “The most comprehensive [analysis] undertaken to date” of the contribution of diet and lifestyle factors to cancer incidence in the UK.

The missing 40%

The report, commissioned by the charity Cancer Research UK, estimates that 43% of new cancers in the UK in 2010 were due to largely preventable dietary and lifestyle factors. Comments below stories in the UK media were quick to point out that, by the study’s reckoning, nearly 60% of cancers are unavoidable.

However, reliable sources state that the genetic contribution to cancer is in the range of 1% to 20%. So let’s assume, for the sake of argument, that the genetic contribution is 20% across the board. If 43% of cancers are down to lifestyle and diet, that leaves 37% unaccounted for! The authors appear to be missing a whopping 40% of cases – and that’s being charitable.

Let’s take a look at some of the specific areas addressed in the study.

Fruit and veg: a superficial analysis

From the outset, it’s important to note that every analysis in the new study consisted entirely of statistical modelling, so any conclusions must be taken with a pinch of (refined) salt. The authors looked only at the effect of low intakes of fruit and non-starchy vegetables on the risk of certain cancers – ‘low’ in this case meaning less than the ‘5-a-day’ recommended by the UK Department of Health. This recommendation is based on no firm evidence whatsoever, as the authors indirectly admit: “The report of the Committee on Medical Aspects of Food Nutrition Policy...recommended increasing consumption of all [fruits and vegetables], an advice [sic] that seems to have motivated the Department of Health in promoting its ‘5-a-day’ programme.” Did they look closely at the effect of organic versus conventionally grown produce, or at the effects of individual phytonutrients in different fruits and vegetables? Did they consider how food preparation methods affect the levels of cancer-protective nutrients in fruit and veg? Er, no. It hardly matters what the results were, as the authors’ methods have barely a nodding acquaintance with either science or reality.

Smoking: over-egging the pudding?

Did you know smoking is bad for you? The vast majority know this already…people, it seems, don’t mind engaging in unhealthy habits, whether it’s smoking or eating an unhealthy diet. What people need help with is having better reasons or incentives to engage in more healthy lifestyles. All the same, the authors of the Cancer Research UK study obviously think we haven’t got the message yet. “Tobacco smoking causes cancers of the lung, larynx, oral cavity and pharynx, paranasal sinuses, oesophagus, stomach, pancreas, liver, kidney, ureter, bladder, uterine cervix...bone marrow, cancers of the colon and rectum, and mucinous tumours of the ovary.” Their results show that, “85% of [UK] lung cancer cases in men are attributable to smoking, and in women the percentage is 80%...36,102 (22.8% of the total) cancers in men and 23,722 (15.2% of the total) in women are attributable to smoking tobacco (currently, or in the past)...14–15% of lung cancer cases among individuals who have never smoked are estimated to be due to exposure to [environmental or ‘second-hand’ tobacco smoke].”

Wow. Nasty stuff indeed. But these results are not all they seem. For a start, the authors rely heavily on epidemiological studies performed by Sir Richard Doll, whose work was largely discredited after his death in 2005. It was revealed that, for over 20 years, he received and failed to disclose regular and substantial consultancy fees from chemical and biotechnology companies, including Monsanto, ICI, Dow Chemicals and the Chemical Manufacturers Association. In fact, Richard Peto, author of the new study’s foreword, was Doll’s co-author on numerous papers.

To calculate the incidence of lung cancer specifically due to smoking in the UK, the authors simply subtracted the estimated numbers of lung cancer cases in people who never smoked from the observed lung cancer cases. They don’t state whether the observed cases they cite occurred in smokers, but we’ll give them the benefit of the doubt. However, nowhere do the authors even attempt to establish whether the observed lung-cancer cases might be due to something other than smoking; they merely assume that smoking is the cause. Neither do the stratify smokers according to the number of cigarettes smoked per day, or whether they smoked organic, roll-up tobacco in chlorine-free papers, Gauloises or Marlboro Reds. And nowhere do the authors address the strong possibility that lung cancer is a different disease among smokers and non-smokers – possibly because it would further invalidate their methods.

We are not trying to downplay the risks of smoking – what interests us is the high likelihood that this study exaggerates the risks of smoking, certainly in terms of lung cancer risk. The authors, of course, make no reference to Richard Doll’s controversial statement made in a BBC interview in 2001: “The effects of other people smoking in my presence is so small it doesn't worry me”. And if smoking is blamed for more cases of lung cancer than it causes, something else is let off the hook. Speaking of which...

‘Occupational exposure’ – AKA giving industry a free ride

According to the authors, only 15 potentially carcinogenic environmental pollutants are worthy of inclusion in their analysis. These substances were selected, by an undisclosed process, from lists of substances deemed ‘carcinogenic’ or ‘probably carcinogenic’ to humans by the International Agency for Research on Cancer (IARC). As such, only certain occupations that come into contact with these very specific substances are said to be ‘at risk’ in the authors’ analysis – which explains why they came up with an ‘occupational exposure’ rate of only 3.7% of all UK cancer cases in 2010.

In truth, everyone – and not just people in very specific occupations, as the authors would have us believe – is exposed to a cocktail of environmental pollutants every day. Many people’s houses can be a major source of exposure: carpets, mattresses and personal care products can all be very significant sources of toxic chemical exposure. While all these chemicals may be used legally, the vast majority of these substances have not been thoroughly researched and characterised before being released into the environment. Interactions between these chemicals, either in the environment or within our bodies, may increase the risk of certain cancers. However, the effect of mixtures of chemicals, and the fact that the total chemical load is determined by both individual pollutants and interactions between them, is quietly ignored by industry and government scientists.

Readers should see what organisations like the Cancer Prevention Coalition, headed up by Dr Samuel Epstein, say about the chemicals around us. They believe that we can massively reduce our cancer risk simply by increasing our awareness of the hundreds of carcinogens and ‘latent’ carcinogens to which we are potentially exposed every day. Cancer Research UK’s report makes no attempt to increase public knowledge of these issues.

By not addressing these issues and only looking at cancer risks associated with a very limited range of chemicals, the authors are likely to have massively underestimated the contribution of environmental pollution to cancer – while hiding at least some of these cases among inflated figures for smoking-related lung cancer.

And there’s more

Other problems with this analysis include:

• Blaming excessive ultraviolet radiation (sunlight) exposure for 82–90% of melanoma cases, or 3.5% of all new cancer cases. This fails to take into account the cancer risks of vitamin D deficiency, the cancer-protective effects of sunshine or the risks of certain sunscreens. And besides, the entire melanoma ‘epidemic’ may be the result of misclassifying benign growths and malignancies
• Not considering the contribution of electromagnetic radiation to cancer risk
• For no apparent reason and with no explanation, the authors assumed that, “The increase in [colorectal cancer] risk is a logarithmic function of intake of meat,” such that “The [colorectal cancer] risk is increased by 0.0025 for each gram of meat consumed”. They worked from the assumption that red meat should not be eaten at all – “we assume that the optimum (or target) is zero consumption” – and failed to compare the effects of organic versus non-organic meat, or of meat from grass-fed versus grain-fed animals. Finally, they considered processed and unprocessed meat together, because to do so otherwise would be difficult (diddums) and besides, they were only interested in the colorectal cancer risk associated with any meat consumption
• Not considering the contribution to cancer rates of wheat, sugar or dairy consumption, or of aspartame consumption – the latter, of, course, is because it’s ‘safe’, or so we’re told

Have you had enough yet?

So, upon close inspection, this is yet another study with hidden aims distinct from its stated goal of public education: that is, to push the establishment view of cancer as being largely unavoidable and only marginally associated with industrial chemicals in the environment. At the same time, readers who take the study’s advice on board are unlikely to do a lot to actually reduce their cancer risk, with the exception of quitting smoking – and even here, the statistics have been twisted. There is no mention of comprehensive strategies to reduce chemical load, and neither are there dietary recommendations that are essentially cancer preventive, immune modulating and anti-inflammatory.

We are concerned that the effect of this study will be to further perpetuate the cancer racket, where people continue to feed industry by buying into health-destroying behaviour, before finally developing cancer and turning to industry’s cancer wing to be patched up – or not. It does absolutely nothing to cause any kind of a shift in the cancer industry juggernaut, a sector of medicine that has been pushed wildly off course by the profit motive.

Are you as sick of this as we are? By being treated as idiots by people in responsible positions and even charities, apparently? By spurious nonsense like this report being trumpeted as cutting-edge science? And by the resulting confetti of compromised research being used as the justification to continue and entrench more deeply an outdated, inhuman, wasteful and ineffective cancer industry that cares little for health, but believes passionately in profit?

This kind of rubbish is the real pseudoscience. So let’s get out there and start telling people how it is, before it’s too late.

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