259 Breast Cancer Screenings
“Will Save Only One Life”
By Jenny Hope
Last updated at 12:51 AM on 5th August 2010
One drawback of screening is that in some cases the cancer detected does not need treating as sometimes it can heal itself or is very slow growing
Breast cancer screening may be doing more harm than good, a study suggests.
The review found 259 women would have to be screened to prevent one death � and many women would be wrongly diagnosed with life-threatening disease and undergo unnecessary treatment as a result.
The latest research in the British Medical Journal will fuel continuing controversy
over the NHS screening programme, which critics claim is not based on robust evidence.
Professor Klim McPherson, a leading Oxford University epidemiologist commissioned by the BMJ to analyse recent studies, said the fine balance between the benefits and harm of screening have not been properly weighed against each other.
Supporters of screening claim it prevents an estimated 1,400 deaths a year, with two women�s lives saved for every one who receives unnecessary treatment.
But other research says the harm is much greater, with as many as ten women having needless treatment for every life saved.
In addition, for every life saved, up to 500 women will have at least one false alarm that might involve a biopsy procedure, and the extreme anxiety involved in being repeatedly called back for further tests.
Professor McPherson said the UK scenario, based on U.S. statistics, suggests the benefits may have been exaggerated.
Although breast screening reduces the death rate by 14 per cent in the under-60s and by 32 per cent in the under-70s, this is of small benefit because of the relatively low risk of dying from the disease, he said.
At the age of 60, the risk of death from breast cancer over the next 15 years is 1.2 per cent, meaning 259 women in the UK would have to be screened to avoid one death.
Under the NHS breast screening programme, women aged 50 to 69 are invited for routine mammograms or X-rays every three years.
Almost two million women a year take up the invitation for screening.
Professor McPherson said the balance of harm and benefit is not made clear to women.
He said: �Individual benefit from mammography is thus very small, but this is not widely understood.
�In part, this is due to obfuscation from organisers of mammography services assuming that a positive emphasis is needed to ensure reasonable compliance.�
He added: �We all need to understand better how a national programme of such importance could exist for so long with so many unanswered questions.�
A recent review carried out by Danish experts found �no convincing evidence� that screening saves 1,400 lives annually.
Improvements in survival rates in recent years are more likely to be down to advances in treatment rather than screening, it said.
More than 45,000 women are diagnosed with breast cancer each year in the UK and more than 12,000 die from the disease.
Professor Julietta Patnick, director of the NHS Cancer Screening Programmes, said: �The BMJ is wrong to suggest there is no evidence to support breast screening � there is an abundance.�
Dr Caitlin Palframan, of Breakthrough Breast Cancer, said: �Based on the current published evidence, we firmly believe the benefits of breast screening outweigh the risks.
�We encourage all eligible women to attend their breast screening appointments.�