Highlights:
– Annual screening in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination
– .Canada decided to compare breast cancer incidence and mortality up to 25 years in over 89,000 women aged 40-59 who did or did not undergo mammography screening
– During the 25 year study period, 3,250 women in the mammography arm and 3,133 in the control arm were diagnosed with breast cancer and 500 and 505, respectively, died of breast cancer
– Furthermore, the study shows that 22% of screen detected breast cancers were over-diagnosed
* 25-year study from Canada published on bmj.com today. FEB 2014 Continue reading “Annual screening does not cut breast cancer deaths, suggests Canadian study”
Tag: Breast cancer screening
Harms from breast cancer screening outweigh benefits if death caused by treatment is included
Contact: Emma Dickinson edickinson@bmjgroup.com 44-020-738-36529 BMJ-British Medical Journal
Cancer expert remains to be convinced by breast screening review
Harms from breast cancer screening outweigh benefits if death caused by treatment is included
Michael Baum, Professor emeritus of surgery at University College London says that, while deaths from breast cancer may be avoided, any benefit will be more than outweighed by deaths due to the long term adverse effects of treatment.
He estimates that, for every 10, 000 women invited for screening, three to four breast cancer deaths are avoided at the cost of 2.72 to 9.25 deaths from the long term toxicity of radiotherapy.
These figures contrast with an independent report on breast cancer screening, led by Sir Michael Marmot and published in November last year. Marmot and his committee were charged with asking whether the screening programme should continue, and if so, what women should be told about the risks of overdiagnosis.
They concluded that screening should continue because it prevented 43 deaths from breast cancer for every 10,000 women invited for screening.
The downside was an estimated 19% rate of overdiagnosis: 129 of the 681 cancers detected in those 10,000 women would have done them no harm during their lifetime. However, those women would have undergone unnecessary treatment, including surgery, radiotherapy and chemotherapy.
But despite this higher than previous estimate of overdiagnosis, they concluded that the breast screening programme should continue.
The report also judged that screening reduces the risk of dying from breast cancer by 20%. But Professor Baum disputes these figures, saying the analysis takes no account of improvements in treatment since these trials were done, which will reduce the benefits of screening. Nor does it make use of more recent observational data.
With these data included, estimated rates of overdiagnosis as a result of screening increase to up to 50%, he argues.
This is important because it can change the decisions women make when invited for screening. In a study also published today, researchers at the University of Sydney explored attitudes to screening in a sample of 50 women. Many of the women were surprised when they were told about overdiagnosis and most said they would attend screening if overdiagnosis rates were 30% or lower, but a rate of 50% made most of them reconsider.
An accompanying editorial points out that the harms of screening will reduce as more effective diagnostic processes develop to inform less harmful and more personalised treatments. In the meantime, it says women need up to date and transparent information about the benefits and harms of screening to help them make informed choices.
Breast cancer screening saves lives, says study??? that screening only narrowly decreased risks that a 50-year-old woman would die from breast cancer within 10 years — from 0.53 percent to 0.46 percent.
Engineering Evil Note: There seems to be conflicting studies being utilized to favor screening. I found this report stating that they used no current data for the meta analysis. The data they claimed to have used here was over 20 years old. I am withholding my humble opinion to see if there were current studies, and if they used the superior MRI overt he antiquated mammograms. There seems to be a few different press releases quoting different studies, in addition now to a few broken links to those reports.
Breast cancer screening saves lives, says study
PARIS (AFP) Benefits of preemptive breast cancer screening outweigh the risks, a study said Tuesday, insisting the practice saves thousands of lives.The new research adds to the debate about the dangers of overdiagnosis, which sees some women undergo invasive treatment for cancers that would never have made them ill or even been diagnosed were it not for the scans.”Breast screening extends lives,” concluded a panel of researchers in The Lancet medical journal.
The team had analysed data from other trials conducted over many years in Britain, where women aged 50 to 70 are invited for a screening mammogram every three years.
The data, it said, pointed to a 20 percent reduction in mortality — or one death prevented for every 180 women screened.
This meant that the UK screening programmes “probably prevent about 1,300 breast cancer deaths every year,” said the report.
But there is a cost.
Nearly 20 percent of breast cancer diagnosed by screening would never have caused any problems, said the study.
The panel, set up to advise British policymakers, estimated that among every 10,000 women invited to screening from the age of 50 in the Britain, 681 cancers would be discovered, of which 129 would be overdiagnoses, and 43 deaths prevented.
The report showed that “the UK breast-screening programme extends lives and that, overall, the benefits outweigh the harms,” The Lancet wrote in an editorial.
“Women need to have full and complete access to this latest evidence in order to make an informed choice about breast cancer screening.”
The team conceded there were limitations to its work, including that all the data scrutinised was more than 20 years old.
Cancer experts have been at loggerheads for years about whether the benefits of screening outweigh the harm of overdiagnosis.
All cancer, once picked up in the screening process, is treated, often with surgery as well as radio- and chemotherapy, as it is impossible to tell which growths would have remained undetected for the remainder of a woman’s life.
In August, medical experts Steven Woloshin and Lisa Schwartz wrote in the British Medical Journal (BMJ) that screening only narrowly decreased risks that a 50-year-old woman would die from breast cancer within 10 years — from 0.53 percent to 0.46 percent.
Up to half of women screened annually over 10 years experienced at least one false alarm that required a biopsy, they said.
And in 2010, a report in the New England Journal of Medicine said mammograms have only a “modest” impact on reducing breast cancer deaths.
The latest panel had been created by the national cancer director for England, Mike Richards and Cancer Research UK chief executive officer Harpal Kumar.
Its work, said The Lancet, “should begin to lay the benefits versus harm controversy to rest”.
http://www.afp.com/en/news/topstories/breast-cancer-screening-saves-lives-says-study
US cancer body oversells mammograms: experts
2 Aug 2012
Medical experts on Friday accused a major US breast cancer foundation known for its high-profile “pink ribbon” campaign of overselling pre-emptive mammography and understating the risks.
The Susan G. Komen for the Cure foundation uses misleading statistics in its pro-screening campaigns, two doctors from The Dartmouth Institute for Health Policy and Clinical Practice in New Hampshire wrote in the BMJ medical journal.
“Unfortunately, there is a big mismatch between the strength of evidence in support of screening and the strength of Komen’s advocacy for it,” professors Steven Woloshin and Lisa Schwartz wrote.
They take issue with a Komen poster comparing the 98-percent five-year survival rate for breast cancer when caught early, with a of 23-percent rate for later diagnosis.
Comparing the two figures did not tell you anything about the benefits of screening, they argued, and in reality a mammogram only narrowly decreases the chances that a 50-year-old woman will die from breast cancer within 10 years from 0.53 percent to 0.46 percent.
Breast cancer treatments are more effective today, and some question whether screening mammography has any benefit whatsoever, wrote the pair.
They accused Komen of overlooking the potential harms, with up to half of women screened annually over 10 years experiencing at least one false alarm that requires a biopsy.
Screening also results in overdiagnosis — detecting cancers that would never have killed or even caused symptoms in a person’s lifetime, and unnecessary treatment.
“The Komen advertisement campaign failed to provide the facts,” said the piece. “Worse, it undermined decision making by misusing statistics to generate false hope about the benefit of mammography screening.”
In 2010, a report in the New England Journal of Medicine said mammograms have only a “modest” impact on reducing breast cancer deaths.
Komen, in a response to the BMJ comment, insisted that early detection enables early treatment, which gives the best shot at survival.
“Everyone agrees that mammography isn’t perfect, but it’s the best widely available detection tool that we have today,” said Chandini Portteus, the foundation’s vice president of research, evaluation and scientific programmes.
“We’ve said for years that science has to do better, which is why Komen is putting millions of dollars into research to detect breast cancer before symptoms start, through biomarkers, for example.”
In February, Komen was embroiled in a controversy over its decision to stop funding for an abortion clinic group in the United States.
New study supports claim that breast screening may be causing more harm than good
Requested Repost from Dec 2011
Research: Possible net harms of breast cancer screening: Updated modelling of Forrest report
A new study published on bmj.com today supports the claim that the introduction of breast cancer screening in the UK may have caused more harm than good.
Harms included false positives (abnormal results that turn out to be normal) and overtreatment (treatment of harmless cancers that would never have caused symptoms or death during a patient’s lifetime). This may be because the cancer grows so slowly that the patient dies of other causes before it produces symptoms, or the cancer remains dormant or regresses.
It shows that the harms of screening largely offset the benefits up to 10 years, after which the benefits accumulate, but by much less than predicted when screening was first started.
The Forrest report in 1986, which led to the introduction of breast cancer screening in the UK, estimated the number of screened and unscreened women surviving each year over a 15-year period. Costs and benefits were measured in quality adjusted life years or QALYs (a combined measure of quantity and quality of life) but it omitted harms.
It suggested that screening would reduce the death rate from breast cancer by almost one third with few harms and at low cost.
Since the Forrest report, the harms of breast cancer screening have been acknowledged. So, researchers at the University of Southampton set out to update the report’s survival estimates by combining the benefits and harms of screening in one single measure.
The results are based on 100,000 women aged 50 and over surviving by year up to 20 years after entry to the screening programme.
Inclusion of false positives and unnecessary surgery reduced the benefits of screening by about half. The best estimates generated negative net QALYs for up to eight years after screening and minimal gains after 10 years.
After 20 years, net QALYs accumulate, but by much less than predicted by the Forrest report.
The authors say more research is needed on the extent of unnecessary treatment and its impact on quality of life. They also call for improved ways of identifying those most likely to benefit from surgery and for measuring the levels and duration of the harms from surgery. From a public perspective, the meaning and implications of overdiagnosis and overtreatment need to be much better explained and communicated to any woman considering screening, they add.
However, the continuing uncertainty surrounding the extent of overtreatment is apparent in a study of French women published on bmj.com last month, which put overdiagnosis of invasive breast cancer due to screening at around 1%.
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Mammography screening shows limited effect on breast cancer mortality in Sweden
Breast cancer mortality statistics in Sweden are consistent with studies that have reported that screening has limited or no impact on breast cancer mortality among women aged 40-69, according to a study published July 17 in the Journal of The National Cancer Institute.
Since 1974, Swedish women aged 40-69 have increasingly been offered mammography screening, with nationwide coverage peaking in 1997. Researchers set out to determine if mortality trends would be reflected accordingly.
In order to determine this, Philippe Autier, M.D., of the International Prevention Research Institute (iPRI) in France and colleagues, looked at data from the Swedish Board of Health and Welfare from 1960-2009 to analyze trends in breast cancer mortality in women aged age 40 and older by the county in which they lived. The researchers compared actual mortality trends with the theoretical outcomes using models in which screening would result in mortality reductions of 10%, 20%, and 30%.
The researchers expected that screening would be associated with a gradual reduction in mortality, especially because Swedish mammography trials and observational studies have suggested that mammography leads to a reduction in breast cancer mortality. In this study, however, they found that breast cancer mortality rates in Swedish women started to decrease in 1972, before the introduction of mammography, and have continued to decline at a rate similar to that in the prescreening period. “It seems paradoxical that the downward trends in breast cancer mortality in Sweden have evolved practically as if screening had never existed,” they write. “Swedish breast cancer mortality statistics are consistent with studies that show limited or no impact of screening on mortality from breast cancer.”
The researchers do note certain limitations of their study—namely, that it was observational, so unable to take into account the potential influence of other breast cancer risk factors such as obesity, which may have masked the effect of screening on mortality. They also write that population mobility may have biased the results.
In an accompanying editorial, Nereo Segnan, M.D., MSc Epi, CPO Piemonte, of the Unit of Cancer Epidemiology at ASO S Giovanni Battista University Hospital in Italy and colleagues write that, in the assessment the efficacy of the introduction of screening, the paradox is that descriptive analyses of time trends of breast cancer mortality rates are used to confute the results of incidence based mortality studies, employing individual data and conceived for overcoming some of their limitations, or of randomized trials.
The conclusion by Autier et al that the 37% decline in breast cancer mortality in Sweden was not associated with breast cancer screening seems therefore difficult to justify and partially unsupported by data (two groups of Swedish Counties do show a mortality decrease that, according to the stated criteria, could be linked to screening).
They also feel that “it is time to move beyond an apparently never-ending debate on at what extent screening for breast cancer in itself conducted in the seventies through the nineties of the last century has reduced mortality for breast cancer, as if it was isolated from the rest of health care …. The presence of an organized screening program may have promoted the provision of more effective care by monitoring the treatment quality of screen-detected cancers and by favoring the creation of multidisciplinary units of breast cancer specialists”.
In another accompanying editorial, Michael W. Vannier, M.D. of the Department of Radiology at the University of Chicago Medical Center, feels that it’s hard to see mortality reduction as a screening benefit because outliers such as the natural history of the disease, along with the frequency of screening as well as the duration of follow up may misrepresent the time patterns in the mortality reductions. “We know that isolating screening as an evaluable entity using death records fails to reveal major benefits,” he writes, adding that even if screening were 100% effective, the number of deaths may remain unchanged. Still he feels that without a better alternative, mammography screening will continue to be used. “As our tools improve, we can begin to fully realize the promise of breast cancer screening to arrest this dread disease at its earliest stage with the least morbidity and cost.”
