Women may undergo unnecessary surgery or receive false positive results, research shows
Women may suffer negative consequences as a result of breast cancer screening, new research claims. Photograph: Burger/Phanie / Rex Features
The controversy over the value of breast cancer screening has been reopened by a study which claims that it does women more harm than good.
Women may suffer negative consequences as a result of the screening programme such as unnecessary surgery to remove harmless cancers that posed them no risk, according to research published in the British Medical Journal.
The findings also highlight the possibility of women receiving "false positives", or results which are initially classed as abnormal but later turn out to be unproblematic. The findings are the latest evidence to emerge which challenges the usefulness of breast cancer screening and warns that it can damage women.
Criticism of the screening programme has prompted the Department of Health (DH) to ask Professor Sir Mike Richards, the government's cancer tsar, to commission a review of the evidence alongside Harpal Kumar, chief executive of Cancer Research UK, from an independent panel of experts who have not previously researched breast screening. That is intended to find consensus because "we know that some scientists differ in their views towards screening", a health department spokesman said.
The study, led by James Raftery, professor of health technology assessment at Southampton University, analysed data from the 1986 Forrest report, which led to screening being introduced in the UK. The Forrest report said the value of screening could be measured by looking at quality adjusted life years (QALYs), which measure both the quality and quantity of extra life gained. Screening would cut the number of women dying of breast cancer by a third, it suggested, and there would be no harmful impact.
Forrest said there would be about 3,000 QALYs over 20 years for every 100,000 women who were invited to be screened. But Raftery and colleagues' analysis of 100,000 women aged 50 or over disputes the Forrest conclusions. This latest paper claims once harmful effects are included, the QALY benefits are fewer: only 1,500 QALYs after 20 years – half Forrest's estimates.
"At up to eight years the harms generally outweigh the benefits but at 20 years there are greater positive benefits. Nevertheless, either way the benefit to patients is less than was stated in Forrest", said Raftery. Most women who have surgery to remove a suspected cancer do not need the treatment, he added.
"There are lots of women around who have had surgery who believe their lives were saved when in fact only around one in 10 have had their life saved", he said.
The health department said the study had not altered its belief in screening. "Our advice has not changed – we urge all women to go for breast screening when invited. The best available evidence shows that screening saves lives by detecting cancers earlier than they would otherwise have been."Our screening programme has always been regularly scrutinised and evaluated", said a spokesman. Women between 50 and 70 are currently invited for screening but that is being extended to those aged 47 up to 73.
Cancer charities are also continuing to defend screening. "We believe breast screening is vital as it can detect breast cancer at the earliest possible stages when no other symptoms are obvious", said Dr Caitlin Palframan, the policy manager at Breakthrough Breast Cancer. The new study "is just one of many analyses of existing screening data", she said.
Catherine Priestly, a clinical nurse specialist at Breast Cancer Care, said calls to its helpline show that "the differing opinions on screening are causing confusion and anxiety for many people". She hoped the review "will bring clarity to this issue and for those attending screening", she added.
Women may suffer negative consequences as a result of the screening programme such as unnecessary surgery to remove harmless cancers that posed them no risk, according to research published in the British Medical Journal.
The findings also highlight the possibility of women receiving "false positives", or results which are initially classed as abnormal but later turn out to be unproblematic. The findings are the latest evidence to emerge which challenges the usefulness of breast cancer screening and warns that it can damage women.
Criticism of the screening programme has prompted the Department of Health (DH) to ask Professor Sir Mike Richards, the government's cancer tsar, to commission a review of the evidence alongside Harpal Kumar, chief executive of Cancer Research UK, from an independent panel of experts who have not previously researched breast screening. That is intended to find consensus because "we know that some scientists differ in their views towards screening", a health department spokesman said.
The study, led by James Raftery, professor of health technology assessment at Southampton University, analysed data from the 1986 Forrest report, which led to screening being introduced in the UK. The Forrest report said the value of screening could be measured by looking at quality adjusted life years (QALYs), which measure both the quality and quantity of extra life gained. Screening would cut the number of women dying of breast cancer by a third, it suggested, and there would be no harmful impact.
Forrest said there would be about 3,000 QALYs over 20 years for every 100,000 women who were invited to be screened. But Raftery and colleagues' analysis of 100,000 women aged 50 or over disputes the Forrest conclusions. This latest paper claims once harmful effects are included, the QALY benefits are fewer: only 1,500 QALYs after 20 years – half Forrest's estimates.
"At up to eight years the harms generally outweigh the benefits but at 20 years there are greater positive benefits. Nevertheless, either way the benefit to patients is less than was stated in Forrest", said Raftery. Most women who have surgery to remove a suspected cancer do not need the treatment, he added.
"There are lots of women around who have had surgery who believe their lives were saved when in fact only around one in 10 have had their life saved", he said.
The health department said the study had not altered its belief in screening. "Our advice has not changed – we urge all women to go for breast screening when invited. The best available evidence shows that screening saves lives by detecting cancers earlier than they would otherwise have been."Our screening programme has always been regularly scrutinised and evaluated", said a spokesman. Women between 50 and 70 are currently invited for screening but that is being extended to those aged 47 up to 73.
Cancer charities are also continuing to defend screening. "We believe breast screening is vital as it can detect breast cancer at the earliest possible stages when no other symptoms are obvious", said Dr Caitlin Palframan, the policy manager at Breakthrough Breast Cancer. The new study "is just one of many analyses of existing screening data", she said.
Catherine Priestly, a clinical nurse specialist at Breast Cancer Care, said calls to its helpline show that "the differing opinions on screening are causing confusion and anxiety for many people". She hoped the review "will bring clarity to this issue and for those attending screening", she added.