Findings dismiss value of breast screens

By ANNE BESTON

Screening women for breast cancer does not prevent deaths and results in more women having unnecessary mastectomies, says one of the most exhaustive reviews undertaken.

The conclusions, published in the Lancet medical journal, have divided health researchers over the benefits of mammographies, one of the mainstays of health screening in the Western world.

The review, by Danish researchers Dr Peter Gotzsche and Ole Olsen, comes two years after their original findings, questioning if breast-screening programmes were useful, sparked a furore.

The pair, from the Nordic Cochrane Centre, extensively reviewed the data and say this has reinforced their original conclusions.

However, Dr Brian Cox, chairman of the group set up by New Zealand's Health Funding Authority to monitor BreastScreen Aotearoa, said the majority medical opinion was still that breast screening did save lives and women should continue to have mammographies.

The Lancet report says not only is there no reliable evidence that breast screening reduces death rates, but that unnecessary mastectomies and tumourectomies (removal of tumours) have increased 30 per cent since screening programmes began.

"Screening identifies some slow-growing tumours that would never have developed into cancer in the women's remaining lifetimes."

New Zealand women have one of the highest breast cancer rates in the world, with more than 600 women a year dying from the disease.

This country spends $22 million a year on its nationwide breast screening programme, which offers women aged between 50 and 64 a free mammogram every two years.

Dr Cox said yesterday that while there was some debate about the effectiveness of breast screening, "the majority of us accept that breast screening done with proper quality assurance reduces cancer mortality by 20 to 30 per cent".

He also questioned the data on which Dr Gotzsche and Mr Olsen based their findings.

The researchers reviewed data from all major clinical trials on mammography over the past 30 years in the United States, England, Scotland and Finland, which were used as the basis for setting up breast-screening programmes around the world.

They say the most reliable trials did not show a reduced death rate when breast screening was used.

The trials were set up using a method designed by the Cochrane Collaboration, an international non-profit organisation to review healthcare programmes throughout the world.

The Cochrane group's evaluations of medical treatments are generally viewed as being of the highest quality.

But when Dr Gotzsche and Mr Olsen submitted their work, the Cochrane group refused to publish it unless they made changes.

Lancet editor Richard Horton has accused Cochrane of trying to erode academic freedom.

nzherald.co.nz/health