The prime minister and health secretary have criticised the NHS on cancer, but new figures suggest the service is a world leader

David Cameron and Andrew Lansley's repeated criticisms of the NHS's record on cancer have been contradicted by new research that shows the health service to be an international leader in tackling the disease.

The findings challenge the government's claims that NHS failings on cancer contribute to 5,000-10,000 unnecessary cancer deaths a year, which ministers have used as a key reason for pushing through their radical shakeup of the service.

In fact, the NHS in England and Wales has helped achieve the biggest drop in cancer deaths and displayed the most efficient use of resources among 10 leading countries worldwide, according to the study published in the British Journal of Cancer.

"These results challenge the feeble justification of the government's changes, which appear to be based upon overhyped media representation, rather than hard comparable evidence. This paper should be a real boost to cancer patients and their families because the NHS's performance on cancer is much better than the media presents. It challenges the government's assertion that the NHS is inefficient and ineffective at treating cancer – an argument for reforming the NHS," said Prof Colin Pritchard, a health academic at Bournemouth University.

He co-wrote the research with Dr Tamas Hickish, a consultant medical oncologist at Poole and Royal Bournemouth and Christchurch hospitals in Dorset.

The research shows that ministers have misrepresented the NHS's record on cancer in order to gain support for their unpopular shakeup, said Pritchard.

The prime minister and the health secretary have said that both survival and death rates from the disease in Britain are low by international standards. Cameron, for example, claimed during last year's general election campaign that Britain had a higher rate of cancer deaths than Bulgaria.

The authors studied cancer mortality and the amount of GDP spent on healthcare between 1979 and 2006 in England and Wales and nine other countries, including Germany, the US, Spain, Japan and France.

While cancer deaths fell everywhere, England and Wales saw the biggest drop in mortality among males aged 15-74 – down 31%. While six countries saw falls of at least 20%, England and Wales – which in 1979-81 had the third highest rate with 4,156 deaths per million men – improved the most, achieving the fifth lowest rate among the 10 countries by 2004-06 with 2,869 deaths per million. Among men aged 55-64 and 65-74, who are more likely to get cancer, mortality dropped by 35% and 28%.

While mortality among women the same age declined by less, at 19%, that was the third biggest improvement after Japan (23%) and Germany (20%).

And the NHS was the most efficient of the 10 countries at reducing cancer mortality ratios once the proportions of GDP spent on healthcare were compared, the study found. While England and Wales spent less on health than most others, they achieved the biggest overall annual fall in cancer mortality over the 27-year period, of 900 deaths per million. Once average GDP spending on healthcare was compared, the NHS saw the biggest fall in male and female cancer deaths of an extra 119 lives a year per 1% of GDP spent, ahead of the Netherlands (74) and almost double that in Germany (68), France (67) and Japan (60).

"That shows how good England and Wales are on cancer care, relative to spend. We do significantly more with proportionately less. It means that 34,484 people are alive today that wouldn't have been if things had not improved since 1980," said Pritchard.

Two authoritative studies have concluded that cancer survival rates in the UK have lagged behind those in comparable major developed countries, though experts dispute which indicators give the most accurate picture of Britain's cancer performance. For example, Prof John Appleby, chief economist at the King's Fund health thinktank, published research in the British Medical Journal earlier this year which disputed the portrayal of Britain as "the sick man of Europe" and argued that cancer survival rates had been improving, significantly in the case of breast cancer.

Duleep Allirajah, policy manager at Macmillan Cancer Support, said: "In the past 10 years cancer services in the UK have improved dramatically. Waiting times have decreased and services have been modernised." But, with cancer survival improving, the NHS now has to address new challenges, notably improving care for patients who have undergone treatment.

"Far too many people in the UK still experience sometimes serious problems related to their cancer treatment. For many these can persist up to 10 years after treatment. The focus now must be for the government and the NHS to address the issues of aftercare and making sure cancer is treated as a long term condition," said Allirajah.

Pritchard said: "David Cameron and Andrew Lansley are happier with NHS 'bad news' stories rather than, as our research shows, that we should celebrate the NHS which, in monetary terms, is vastly superior to the private healthcare system of the USA.

"Of course we should always be looking to improve. But the only way to judge the NHS is to compare it with other countries, which shows that we are still getting the NHS on the comparative cheap."

The Department of Health declined to respond directly to Pritchard and Hickish's findings. "There is a difference between achieving efficiency and the results patients receive. While it is good that NHS cancer treatment is relatively efficient, we know that the results patients actually get lag behind many other countries," said a spokesman.

"Our cancer strategy is clear – we aim to save 5,000 lives extra every year by 2015 which will bring us up to the level achieved in many other comparable countries. We owe it to patients to deliver standards which are up there with the best in the world," he added.