Thousands of women in England could be undergoing unnecessary and potentially devastating treatment for suspected breast cancer, a new study suggests.
The study, by researchers at the Nordic Cochrane Centre, looked at seven trials investigating both the benefits and negative outcomes associated with breast screening.
They found that for every 2,000 women invited to have mammograms, one would have their life prolonged but 10 would endure potentially devastating and unnecessary treatment.
And another 200 of those women would experience weeks or months of anxiety because of "false positive" findings - the discovery of cell changes that later turned out to be benign.
The findings have prompted a leading doctor to call into question whether or not the NHS breast screening programme should be allowed to continue.
In 2003-4 1.4 million women in England were screened for breast cancer, of whom more than 11,000 had cancers diagnosed. The annual cost of the programme is £75 million.
Professor Michael Baum, professor emeritus of surgery and visiting professor of medical humanities at University College London, was reported as saying that until now his position was that women should make an informed choice based on the facts.
But he added: "This latest evidence shifts the balance even further towards harm and away from benefits.
"If this report stands up, the NHS screening programme should be referred to the National Institute for Clinical Excellence to decide whether it should be closed down."
But Julietta Patnick, director of NHS Cancer Screening Programmes, added: "Over-diagnosis is a fact, but we estimate that for every 2,000 women screened over 10 years, we probably diagnose five who would otherwise not present but we will also save five lives."
The research was led by Dr Peter Gozsche, director of the Nordic Cochrane Centre.
The report concludes: "Breast self-examination does not appear to reduce breast cancer deaths."
It adds: "Breast self-examination or clinical breast examination by a doctor or a nurse have been promoted for many years as screening methods to diagnose breast cancer at an earlier stage in order to decrease the risk of dying from breast cancer.
"The review of data from two large trials of breast self-examination did not find evidence for a beneficial effect of screening, whereas there was evidence for harms in terms of increased numbers of benign lesions identified and an increased number of biopsies performed."
The trials the researchers looked at included one in Russia involving about 120,000 women.Reuse content