Four reasons I won’t have a prostate cancer blood test - Prof Ian Haines

5 December 2014

Four reasons I won’t have a prostate cancer blood test

Ian Haines

Adjunct Clinical Associate Professor & Senior Medical Oncologist and Palliative Care Physician at Monash University

For many men, the down sides of PSA testing outweigh the benefits.

Cancer Council Australia and the Prostate Cancer Foundation of Australia yesterday released new draft guidelines to help GPs counsel men who ask about prostate cancer tests. They advise GPs to explain the pros and cons of testing and, if the man wants to proceed, to give him a prostate specific antigen (PSA) blood test every two years between the ages of 50 to 69.

Over the past few decades public health messages have drummed into us that early detection and treatment of diseases are key to good outcomes. Add to this the celebrity testimonials for prostate tests and non-celebrities who tell us their PSA test “saved their life” and it’s easy to see why men think the tests are beneficial.

While some prostate cancers are harmful and require treatment, many are not. So the prevailing wisdom – that early detection and treatment is best – doesn’t necessarily apply. At least 70% of men over 70 have prostate cancer detected in autopsies, and only 3% of men die because of prostate cancer.

I’m a 60-year-old male oncologist who has practised full-time for 36 years. Having “skin in the game” I’ve followed the testing debate closely since PSA was first used for screening in the early 1990s. Based on the evidence, if I was asymptomatic, I would not choose to have PSA test. Here’s why.

1. PSA is a poor testing tool

Prostate specific antigen (PSA) is an enzyme secreted in large amounts by normal as well as cancerous prostate cells. Only small amounts of PSA leak into circulation from a normal prostate, but this increases with any prostatic disease, benign or malignant.

An elevated PSA very often does not indicate cancer. Just one in four men with a positive PSA test will have prostate cancer.

PSA tests also miss many cancers. A 2003 study found that 21% of men who had a “normal” PSA of 2.6 to 3.9 at the end of a seven-year study did, in fact, have prostate cancer. Of the men with a PSA of 2.5 or less, 15% had cancer.

2. Prostate cancer isn’t like other cancers

The point of a cancer screening test is that it can reliably detect lesions that, if removed, will reduce the chances of that patient later developing a life-threatening cancer.

This is certainly true for polyps and bowel cancer screening. It is also powerfully true for precancerous lesions of the cervix and cervical cancer. It is somewhat true for mammography and precancerous or early invasive breast lesions.

It is not at all true for prostate cancer screening. In the majority of cases, prostate cancer behaves more like an indolent condition and does not pose any threat to the patient’s natural life span. This proportion of men dying of other causes continues to increase in the PSA era.

The only prostate screening study showing an advantage for screening has very serious flaws, which have also been noted by the head of the American Cancer Society Professor Otis Brawley and Professor Richard Ablin, who discovered the prostate specific antigen in the 1970s.

3. Surgery won’t always cure you

The only study comparing radical surgery with no treatment found equivalent outcomes. It concluded:

Among men with localized prostate cancer detected during the early era of PSA testing, radical prostatectomy did not significantly reduce all-cause or prostate-cancer mortality, as compared with observation, through at least 12 years of follow-up. Absolute differences were less than three percentage points.

Radical surgery “cures” six in seven cases of prostate cancer. But this does not remove the uncertainty and doubt for men with prostate cancer, as most of the six in seven who are “cured” did not require treatment and most of the one in seven with dangerous cancers requiring cure will not be helped by the treatment.

4. Detection and treatment comes with side effects

One in six men will be diagnosed with prostate cancer during his lifetime. Their lives will be profoundly changed by this cancer diagnosis, whether or not they proceed with treatment.

I do not want the anxiety, depression and relationship changes that follow diagnosis, radical surgery, active surveillance or any regular monitoring. I do not want to be impotent, which is very likely after radical treatment, or have urinary incontinence.

Even before treatment commences, after an abnormal PSA result, men are referred for a prostate biopsy: a surgical procedure that, even though it can indicate cancer, cannot give reliable information about how that cancer will behave.

I do not want the 1-2% risk of life-threatening infections caused by prostate biopsies.

Bottom line

I’m happy to take active positive steps to improve my health where it is proven that the benefits of the intervention outweigh the costs. But I’m not prepared to have my life ruled by a regular blood test like PSA that has no advantage.

First published in The Conversation

What do the Greens support as alternatives to the burning of fossil fuels?

The recent China/US agreement to reduce CO2 emissions prompted Martin Ferguson, former Labor Minister for Resources and Energy, to publicize a few "energy" facts which raise the question of whether emissions reduction is the real objective for "The Greens". Here is the reaction from my retired financial advisor friend AP to the former Minister's criticism:

"China and US have shown they will act," cheered The Greens' leader, Christine Milne. "The Australian Greens are congratulating the US and China on their agreement to act on global warming and say it's not too late for Australia to get on board."

It's fair to say the Greens and their boosters have used the USA-China accord as a stick with which to beat pretty much anyone outside of the renewable energy sector.

Their rhetoric is symptomatic of a broader malaise; our increasing inability to listen to, analyse, and properly understand the words and numbers underpinning complex policy.

Slogans should not be a substitute for serious discussion or critical thinking.

The question I would like answered is whether the Greens and the wide array of energy dogmatists who cheer them on actually understand - let alone support - any of the energy technologies that underpin the capacity of the two global superpowers to enter into the "Climate Pact" in the first place?

The People's Republic of China has 22 nuclear power reactors operating and a further 26 under construction.

Additional reactors - enough to triple nuclear capacity to at least 58 gigawatts by 2020 - are planned. As a rule of thumb, a typical new-build reactor will generate about 1 gigawatt a year, so it appears there are quite a few new Chinese nuclear power plants on the drawing board.

This will raise the percentage of China's electricity produced by nuclear power from the current 2 per cent, to more than 7 per cent, by 2020. Thereafter, another threefold increase in nuclear capacity (to about 150 gigawatts) is planned by 2030; and then more again by 2040.

Not only does nuclear power offer an enormous opportunity to Australia's uranium exporters, it clearly has a central role to play in China's decarbonisation. Yet the last time I checked, the Australian Greens were trenchantly opposed to the use of - let alone the further development of - this major energy source. Of course, they are not the only people in Canberra to hold such a view.

Hydroelectricity is also incredibly important to any future reduction in China's emissions.

Hydro is the world's leading source of renewables-based electricity and in
2012, it produced more than twice as much power as all other forms of renewables combined. In China, hydropower has long been the single most important source of renewable energy and it will remain so in 2040. China last year brought online a record 31 gigawatt of hydropower.

And while the country's investment in hydro will fall after 2020, this is simply because most of the suitable hydro sites will have been by then developed, not because better or cheaper renewable technologies will have become available. Hydro will still account for about 40 per cent of total energy produced by renewables in China in 2040.

As a party who owes its parliamentary advent to an anti-dam campaign, it is hard to see how the Australian Greens could change the party's opposition to China's - or anyone else's - dam-building.

Now let's look at the USA; a country that is already leading the world in the field of carbon reductions; with emissions today back to levels last seen in the mid-1990s. It is an astounding achievement, but not one born of a carbon price or a Renewable Energy Target. Rather, it has been the rapid and dramatic discovery and use of cleaner burning indigenous natural gas supplies that has cleaned up the American power system.

The scale of the USA shale gas expansion is immense. In the few years immediately following the technological advancements in hydraulic fracturing and horizontal drilling that made vastly more resources commercially available, the price of gas fell from more than $13 per gigajoule in 2006, to less than $4 today.

Gas use has soared and gas has displaced coal as the country's leading energy source.

The United States today has 487,286 gas wells in production; a staggering number. And throughout 2014, more than 300 drill rigs have been drilling for gas across the US. The International Energy Agency (IEA) says that in 2040, gas will provide more energy to the USA than coal, wind and solar combined.

And what do The Australian Greens say on natural gas development? They oppose it.

Lastly, the IEA forecasts China will remain the world's largest coal user in
2040 - with consumption three times that of India, the world's second-largest user. Not surprisingly, the IEA says carbon capture and storage (CCS) is an essential mitigation technology.

As part of their "Climate Pact" the US and China aim to use advanced coal technologies, including a major CCS project in China.

The Australian Greens? In 2011, they insisted CCS be excluded from the $10 billion Clean Energy Finance Corporation, set up with the Gillard Government.

Frankly, it is hard to see what Senator Milne was referring to last week when she said: "The Greens will continue to push for true leadership and real action to address the greatest challenge of this century - global warming."

Energy security and climate policy are areas of complex policy. "True leadership and real action" is indeed required.

But it actually consists of sophisticated thinking and rigorous debate; not opportunism"

Just how toxic are the chemicals used in fracking?

Major class of fracking chemicals no more toxic than common household substances

November 12, 2014

The “surfactant” chemicals found in samples of fracking fluid collected in five states were no more toxic than substances commonly found in homes, according to a first-of-its-kind analysis by researchers at the University of Colorado Boulder.

Fracking fluid is largely comprised of water and sand, but oil and gas companies also add a variety of other chemicals, including anti-bacterial agents, corrosion inhibitors and surfactants. Surfactants reduce the surface tension between water and oil, allowing for more oil to be extracted from porous rock underground.

In a new study published in the journal Analytical Chemistry, the research team identified the surfactants found in fracking fluid samples from Colorado, Louisiana, Nevada, Pennsylvania and Texas. The results showed that the chemicals found in the fluid samples were also commonly found in everyday products, from toothpaste to laxatives to detergent to ice cream.

“This is the first published paper that identifies some of the organic fracking chemicals going down the well that companies use,” said Michael Thurman, lead author of the paper and a co-founder of the Laboratory for Environmental Mass Spectrometry in CU-Boulder’s College of Engineering and Applied Science. “We found chemicals in the samples we were running that most of us are putting down our drains at home.”

Imma Ferrer, chief scientist at the mass spectrometry laboratory and co-author of the paper said, “Our unique instrumentation with accurate mass and intimate knowledge of ion chemistry was used to identify these chemicals.”  The mass spectrometry laboratory is sponsored by Agilent Technologies, Inc., which provides state-of-the art instrumentation and support. 

The fluid samples analyzed for the study were provided through partnerships with Colorado State University and colleagues at CU-Boulder.

Hydraulic fracturing, or “fracking,” is a technique used to increase the amount of oil and gas that can be extracted from the ground by forcing fluid down the well. Fracking has allowed for an explosion of oil and gas operations across the country. In the U.S. the number of natural gas wells has increased by 200,000 in the last two decades, according to the U.S. Energy Information Administration.

Among the concerns raised by the fracking boom is that the chemicals used in the fracking fluid might contaminate ground and surface water supplies. But determining the risk of contamination—or proving that any contamination has occurred in the past—has been difficult because oil and gas companies have been reluctant to share exactly what’s in their proprietary fluid mixtures, citing stiff competition within the industry.

Recent state and federal regulations require companies to disclose what is being used in their fracking fluids, but the resulting lists typically use broad chemical categories to describe the actual ingredients.

The results of the new study are important not only because they give a picture of the possible toxicity of the fluid but because a detailed list of the ingredients can be used as a “fingerprint” to trace whether suspected contamination of water supplies actually originated from a fracking operation.

The authors caution that their results may not be applicable to all wells. Individual well operators use unique fracking fluid mixtures that may be modified depending on the underlying geology. Ferrer and Thurman are now working to analyze more water samples collected from other wells as part of a larger study at CU-Boulder exploring the impacts of natural gas development.

Thurman notes that there are other concerns about fracking—including air pollution, the antimicrobial biocides used in fracking fluids, wastewater disposal triggering earthquakes and the large amount of water used—that are important to investigate and ameliorate. But water pollution from surfactants in fracking fluid may not be as big a concern as previously thought.

“What we have learned in this piece of work is that the really toxic surfactants aren’t being used in the wells we have tested,” he said.

GOVERNMENT COMMITS VIRTUALLY NO FUNDS TOWARDS IMPROVING WATER QUALITY WITHIN THE VASSE WONNERUP WETLAND SYSTEM

GOVERNMENT'S RESPONSE TO THE INDEPENDENT EXPERT'S  REPORT ON IMPROVING WATER QUALITY WITHIN THE VASSE WONNERUP WETLAND SYSTEM VERY DISAPPOINTING

The public announcement by the Minister for Water Mia Davies about the state government's response to the independent expert's report on management of the Geographe Bay catchment was a great disappointment.

Her presentation on October 31 to a large crowd of local people vitally interested in preventing further fish deaths contained three main initiatives. These were:

* $200,000 to be given to the Geographe Catchment Council to assist the government in community consultation
* the establishment of a ministerial taskforce to "oversee a long-term strategy to improve water quality and the ecosystem" and
* $4.8 million dollars to connect 126 properties in Quindalup to deep sewerage.

All three initiatives are disappointing for a number of reasons.

The one-off allocation of $200,000 to GeoCatch is not to allow any on-ground works to be implemented, but only to consult and communicate with the local community.

The taskforce will, for the most part, be reinventing the wheel, since the management actions needed to improve water quality have been outlined in documents and reports prepared by GeoCatch over the last 10 years.

The money for deep sewerage connections in Quindalup is equal to $38,000 per property with only minor improvements in water quality to be gained by Toby's Inlet and Geographe Bay.

I was a former member of the GeoCatch board and the former member for Vasse from 1996 to 2005. I'm highly critical of all three initiatives because they lack substance and any long-term commitment to improving water quality in the Vasse Wonnerup wetland system.

GeoCatch has been given a one year allocation of funds with which it has to tell the community what a great job the government is doing. Not one cent of this money is to be spent on water quality improvement, even though GeoCatch was set up in 1997 to be the coordinating body for on-ground improvements.

The ministerial taskforce appears to be an exercise in delaying for a year - until much closer to the next state election - any commitment of funds to allow catchment management actions to be implemented.

The $4.8 million for sewerage connections is more about providing the Water Corporation with a new source of income via wastewater treatment from the 'lucky' 126 properties. As well, deep sewer connections will allow more of these properties to be rezoned for tourist accommodation or higher urban density, so the City of Busselton will be a financial beneficiary of this initiative through an increased rate base.

$4.8 million equals $38,000 being spent per property on deep sewerage, when instead the government could have installed $17,000 Aerobic Treatment Units (ATUs) at each property and given the unspent $2.6 million to GeoCatch or the City to improve water quality in the Vasse Wonnerup wetland area.

Professor Barry Hart, formerly from Monash University in Victoria, was the independent expert called in by the state government in 2013 to provide a review of management needs in the Geographe Catchment.

His report contains 14 recommendations, the first of which - for the state government to establish a single catchment management authority to manage all wetland assets - has been rejected by the state government.

Recommendation 13 - that the government provide $30 million of funding over 10 years for management - has resulted in just $200,000 being committed, less than 1% of the recommended amount.

Dr Hart's review report was welcomed by the local community as it gave them reasonable grounds for hoping that the state government would do something meaningful to better manage water quality in the Vasse Wonnerup wetland system.

Instead, we have had scraps of money offered to GeoCatch, a one year delay before the taskforce reports and money being spent on deep sewerage, a relatively lowly ranked management action.

My relevant background to water quality issues in the Geographe catchment include:
Former president, Geographe Bay Advisory Committee
Former member, Vasse Wonnerup Land Conservation District Committee
Former member, Geographe Catchment Council
Councillor, Busselton Shire Council, 2009-2010
Member for Vasse 1996-2005, including shadow minister for the environment 2001-2004

Shooting Up on Heroin at your Local Polling Place

I'd forgotten how backward and unhelpful the WA Electoral Commission were at election time. Over my almost 30 years of involvement at polling booths on election day, attempts to recycle How To Vote (HTV) cards have become increasingly frustrated by the silly decisions of the Electoral Commission.

On Saturday October 18, I was reminded of the Commission's silliness when I attempted to recycle HTV cards at the Vasse Primary School polling place. As electors left the school assembly area where they were crossed off the electors' list, handed a ballot paper, directed to a booth to mark the paper and then directed to the ballot box, next to the only exit was box for rubbish such as HTV cards. When I asked Lorraine, the person in charge of the polling booth, if I could recover HTV cards from the rubbish box so that I could recycle them on behalf of all the parties who had volunteers handing out HTV cards, I was told that she could not allow me to do so. When I politely but resolutely protested and asked the basis for this ruling, she directed me to her boss Phil who I phoned with the same request. In turn, Phil advised he'd talk to the WAEC's by-election manager and get back to me.

A few minutes later, Phil phoned me back and confirmed that permission to empty the rubbish box would not be given. When I asked him to explain why, he declined to elucidate the WAEC's concerns, other than saying there could be a ballot paper accidentally discarded in the box. When I pointed out that Lorraine has said such ballot papers would not be allowed to be placed in the ballor box, he ceased attempting to explain the decision, instead reiterating the Commission's refusal to allow access to the rubbish box.

So why is the WAEC opposed to anyone - their staff or political party volunteers - recycling HTV cards? As strange as it may seem, they appear to believe it's a occupational health and safety issue. If you think back 15 or so years when heroin was one of the most popular recreational drugs, the WAEC warned that drug users might inject themselves in the privacy of a booth, even though these booths then as now were open and barely concealed a ballot paper, let alone any drug-taking paraphernalia. So, after injecting themselves with heroin, drug users were expected to dispose of the used needles in the rubbish boxes near the polling booth exits.

How many times were heroin users found shooting up in polling booths? None. How many discarded needles were found in rubbish boxes mixed in with HTV cards? None.

But the OHS concerns don't stop there. People coming into the polling booth could bring glass drinking containers in with them, drop them on the floor and the broken glass would have to be cleaned up and disposed of in the rubbish boxes. Of course this could happen, expect that you can't buy non-alcoholic drinks in glass bottles any more.

OK, what if people used the rubbish boxes to dispose of soiled nappies or food scraps? For recent elections, pre-polling has allowed people with reasonable reasons for not being able to vote on polling day to cast a pre-poll vote. Invariably, almost all nursing mothers will find a suitable time to pre-poll rather than run the risk of standing in long queues on polling day with babies in nappies, often under a hot burning sun during a summer election.

Please, WAEC, come clean (excuse the pun!) on why you won't allow polling booth volunteers to empty the rubbish boxes at polling booths so that HTV cards can be recycled. If someone puts a HTV card in the ballot box and throws their ballot paper in the rubbish box , that's not an action that WAEC staff should be held responsible for. If volunteers are happy to run the risk of being cut or injected by a sharp piece of rubbish or putting their hand into a soiled nappy, that's their problem, not yours.

Is it worthwhile trying to recycle HTV cards? Let's do the numbers (but round them off for simpilicity's sake). In a normal state election, there are probably 1.5 million electors. If the four major parties -Liberal, Labor, Nationals, Greens - print enough HTV cards so that, in a worse case scenario, every elector going into a polling booth has a HTV card, then that's six million pieces of paper printed and distributed during the election campaign. Add in an extra million or two to take account of the minor parties' HTV cards and the total could easily hit seven million HTV cards. Forgetting about the number of trees that have to be cut down to meet this need for paper, the cost of printing out seven million, one sided colour A4 pages is probably three cents per page. Total cost - $210,000. If the political parties could reduce their HTV card print run by 50%, in the knowledge that they can recycle HTV cards from the polling booth's rubbish box, that's a worthwhile financial saving for the political parties and their candidates and, thanks to taxpayer funding of election campaigns, the savings could be passed on to taxpayers through reduce public funding.

The WAEC needs to explain why it maintains this absurd ban on the recycling of HTV cards. The risks it perceives to volunteers involved in recyling are non-existent and the financial and environmental benefits are worthwhile.

Peter Gordon is the best candidate in the October 18 Vasse by-election

He may be standing for the Nationals but Peter Gordon is the best person among the candidates for the Vasse by-election on October 18.

During my 8 years as the member for Vasse, I was always on the lookout for those rare people with the necessary qualities to be a good member of Parliament. In particular, I searched for people who provided sound leadership, who had been successful at their chosen career (business, professional, parenting, teaching, etc), who had a moral compass to help steer them when the difficult issues came along and who were mentally and emotionally capable of committing to the long hours, extensive travel, the time away from home as well as the personal abuse which is always directed towards politicians, regardless of their party or  their individual qualities.

In my time as an elected MP, I found just 4 people who I considered had the necessary qualities to be good members of Parliament. The small number is not a reflection on the many other people I interacted with who I believed weren't well suited to a parliamentary life. Instead, it was simply a measure of the significant difficulties associated with being an MP.

Of those 4 people, two were dairy farmers (one male, one female) and one was a geologist (female). None showed any interest in becoming a politician at the time I spoke to them because of their existing business or family demands.

Peter Gordon was the fourth person on my list and, while I suggested his name to various people when the Vasse by-election was announced, I have to admit I never asked Peter direct if he might have been interested in standing. Nonetheless, I was greatly pleased to see him running as a candidate for the Vasse by-election (even if he should have been chosen by the Liberals rather than the Nationals!). Why? Because the interactions I've had with him over the last 10 to 12 years have shown him to be a highly capable leader, a successful business person, committed family man and father and, probably most important of all his qualities, honest. He's also not a bad sort of bloke.

Without reflecting on the other candidates standing for the by-election, all of whom have some good qualities, my assessment is that Peter stands head and shoulders above them all. If elected, I believe he will be an incredibly hard working member of Parliament for Vasse, committed to achieving benefits for all Vasse voters, regardless of their voting preferences. While economic development issues are understandably the primary policy issue at this by-election, Peter is close to the full range of issues that are important to Vasse electors: education, health, water, environment, public housing, agriculture, tourism, police, justice, family services and community development.

Steve Jobs Didn’t Let His Kids Use iPhones Or iPads: Here’s Why.

Steve Jobs is a name which is synonymous with cutting edge, innovative and groundbreaking technology. So it may come as something as a surprise to learn Apple’s former CEO didn’t believe in letting his kids use some of his company’s greatest products – the iPhone and the iPad. And it’s not because the Apple godhead was a closet Samsung fan either.

Jobs, who died in 2011, may have had an instinctive flair for technology but he was a low tech parent who firmly believed in restricting his children’s access to electronic devices. “We limit how much technology our kids use at home,” said Jobs way back in 2010, expressing growing concerns about his children’s gadget use.

As all modern parents know, iPhones and iPads are extremely appealing to children. These little hand-held devices are state-of-the-art toys. Surrogate parents almost, capable of entertaining, distracting, and pacifying children during school holidays and on long car journeys when mom and dad’s attentions are focused elsewhere.

Yet instead of thanking Apple for these extremely convenient parent assistants, should we actually be concerned about the potential harm they may be inflicting upon our youngsters?
Steve Jobs certainly appeared to think so. In a New York Times article published this week, journalist Nick Bilton recalls how he once put it to Jobs that his kids must love the iPod, but to his surprise Jobs replied, “They haven’t used it. We limit how much technology our kids use at home.”

“I’m sure I responded with a gasp and dumbfounded silence. I had imagined the Jobs’s household was like a nerd’s paradise: that the walls were giant touch screens, the dining table was made from tiles of iPads and that iPods were handed out to guests like chocolates on a pillow. Nope, Mr. Jobs told me, not even close.”

And Jobs wasn’t the only technological guru who had substantial concerns about the long-term effects of kids engaging with touch-screen technology for hours on end. Chris Anderson, former editor of Wired, also believes in setting strict time limits and parental controls on every device at home.

“My kids accuse me and my wife of being fascists. They say that none of their friends have the same rules. That’s because we have seen the dangers of technology first hand. I’ve seen it in myself, I don’t want to see that happen to my kids.”

Researchers at the University of California Los Angeles recently published a study which demonstrated that just a few days after abstaining from using electronic gadgets, children’s social skills improved immediately.
Which is definitely food for thought considering recent research showed that an average American child spends more than seven and a half hours a day using smart-phones and other electronic screens.

Jobs was undoubtedly a genius but he didn’t get that way through staring at screens and playing Angry Birds until the early hours or constantly updating his Facebook account. Walter Isaacson, the author of Steve Jobs, spent a lot of time at the Apple co-founder’s home and confirmed that face-to-face family interaction always came before screentime for Jobs.

“Every evening Steve made a point of having dinner at the big long table in their kitchen, discussing books and history and a variety of things. No one ever pulled out an iPad or computer. The kids did not seem addicted at all to devices.”

So the next time the advertising department at Apple, Samsung, or any other major technological corporation attempt to sublimely convince you that life is somehow lacking without their latest little device, remember that the man who started it all, believed somewhat differently.

Article courtesy of  http://www.inquisitr.com/

Aspirin could dramatically cut cancer risk - recommended for 50 to 64 year olds

Aspirin could dramatically cut cancer risk, according to biggest study yet

The Guardian, Wednesday 6 August 2014

 

 

An aspirin a day could dramatically cut people's chances of getting and dying from common cancers, according to the most detailed review yet of the cheap drug's ability to stem disease. More than 130,000 deaths (in the UK) would be avoided over a 20-year period if Britain's 50- to 64-year-olds took a daily aspirin for 10 years, because the beneficial effects continue even when the aspirin is stopped, the authors say.

A research team led by Professor Jack Cuzick, head of the centre for cancer prevention at Queen Mary University of London, concluded that people between 50 and 65 should consider regularly taking the 75mg low-dosage tablets.

Cuzick said that taking aspirin "looks to be the most important thing we can do to reduce cancer after stopping smoking and reducing obesity, and will probably be much easier to implement". In a briefing to journalists, the scientist added that he had been dosing himself for the last four years, keeping the tablets beside his bed. "I take aspirin as part of a bedtime ritual every day and I can achieve that quite easily," he said.

However, to obtain the newfound benefits of the drug, people would have to take aspirin for at least five years and probably 10, the review said. Aspirin was originally developed as a painkiller and treatment for fever and inflammation, but more than a century after it was first synthesised from willow bark, researchers have found more medical uses for it.

It has been demonstrated to reduce the risks of heart attacks and strokes as well as the chances of some cancers. But the big question has been whether the benefits outweigh the harms, because aspirin can cause stomach bleeds, which could be potentially fatal in some people.

Concluding that the benefits outweighed the risks, Cuzick's team, writing in the cancer journal Annals of Oncology, said that by taking low-dose aspirin every day for 10 years, bowel cancer cases could be cut by about 35% and deaths by 40%. Aspirin could reduce rates of oesophageal and stomach cancers by 30% and deaths from them by 35% to 50%.

However, taking aspirin every day for 10 years increases the risk of stomach bleeds among 60-year-olds from 2.2% to 3.6%. In about 5% of those who have a stomach bleed, it could be fatal. Cuzick added that there was evidence that this side-effect could be more common in people who have the bacterium Helicobacter pylori in their stomach, which also causes peptic ulcers. He said people considering embarking on a regime of daily aspirin should talk to their GP and it might be possible to be tested first.

A second risk is stroke. Aspirin is already given to some people to reduce their risk of heart attacks or ischemic stroke, caused by blood clots, which it does by thinning the blood. But it is likely to worsen a haemorrhagic stroke, caused by bleeding in the brain.

The study also shows that 10 years of aspirin reduces heart attacks by 18% and deaths by 5%, but although it reduces stroke numbers by 5%, there is a 21% increase in deaths.

All the cancers in which aspirin has a beneficial effect have some lifestyle causes – from smoking in lung cancer to alcohol in oesophageal cancer and obesity in all of them. Taking aspirin, said Cuzick, "should not be seen as a reason for not improving your lifestyle". The drug, however, would reduce the cancer risk even in people who have a healthy lifestyle, he said.

Increasing numbers of people in middle age are already being prescribed cholesterol-lowering statins to reduce their risk of heart attacks and strokes. Recently there has been an outcry over the "medicalisation" of the population and concern about side-effects – which trial data suggest are less common and less serious than those in aspirin. Cuzick said there was no evidence of any interaction between the two drugs. "In many people, taking both of them is probably a good idea," he said.

However, Cancer Research UK (CRUK)warned that people should speak to their GP before starting on daily aspirin. The charity said it would like to see more research on who should and should not be taking it.

"Aspirin is showing promise in preventing certain types of cancer, but it's vital that we balance this with the complications it can cause – such as bleeding, stomach ulcers, or even strokes in some people," said Dr Julie Sharp, head of health information at CRUK.

"Before aspirin can be recommended for cancer prevention some important questions need to be answered, including what is the best dose and how long people should take it for. And tests need to be developed to predict who is likely to have side-effects. "Given the continued uncertainty over who should take aspirin, Cancer Research UK is funding a number of trials and research projects to make the picture clearer," she said.

Aspirin also has a smaller preventive effect on other major cancers, according to the research paper. It could reduce the number of lung cancers by 5% and deaths by 15%. It could cut prostate cancers by 10% and deaths by 15%, and breast cancers by 10%, with a reduction in deaths of 5%. There would be an overall 9% reduction in the number of cancers, strokes and heart attacks suffered by men and a fall of 7% in women.

Cuzick acknowledged that people generally did not like taking pills for a long period, although, he said, some were "more than happy to take multivitamins for many, many years without any clear evidence of benefit. It is a regular habit." 

As a generic drug – Bayer's patent ran out in the 1930s – there are no profits to be made by big pharmaceutical companies from the estimated 100bn tablets taken around the world every year.

The science – and the warnings

What does the study find?

The risk of both developing and dying from digestive-tract cancers – those of the bowel, stomach and oesophagus – was reduced by about a third in people who took low doses of aspirin daily for 10 years. Cases of breast, prostate and lung cancer were reduced by about 10%, though no effect was seen on other cancers.

What do scientists recommend? For aspirin's anti-cancer benefits to kick in, people needed to have taken aspirin for at least five years from the ages of 50 to 64. Most of the research was based on low 75mg doses. The longer the drug was taken, the better its preventive effects, until the age of 65, after which there was an increased risk of internal bleeding. The study found no benefit in taking aspirin before the age of 50. Scientists recommend that people consult their GP before taking daily aspirin to prevent cancer.

How does aspirin prevent cancer?

There are two theories. First, inflammation in the body causes cells to divide, which increases the risk of them mutating into cancerous forms.

Because aspirin reduces inflammation, it lowers the risk of cancerous cells developing.

Second, cancer cells can piggyback on blood platelets, which help the blood to clot. Aspirin thins the blood by making platelets less sticky, which may also make it harder for them to carry cancer cells and so spread the disease.

What are the risks?

Aspirin can cause bleeding in the stomach and bowel. This can be serious, especially in the over 70s, but rarely affects younger people unless they have an underlying condition.

"My personal advice would be that everyone 50 to 64 should consider taking aspirin. You should talk to your GP first to see if you've got any of the major risk factors for bleeding, but if not I think the benefits substantially outweigh the risks," said the senior author, Prof Jack Cuzick.

Nishad Karim