Breast-cancer screening cuts deaths by a fifth: study

AFP - Programmes to encourage women to undergo mammography screening can reduce breast-cancer fatalities by more than a fifth, a study published in The Lancet on Saturday says.

The research is an overview of four individual trials covering 247,000 Swedish women aged from 38 to 75, who were either given a mammography or not and whose health was then monitored over a long time -- nearly 16 years on average.

Breast-cancer deaths among those who had been screened numbered 511, while the toll among those who had not been screened was 584, a difference of 21 percent. The biggest reductions in the death rate were among women aged 55 and above.

"The advantageous effect of breast screening on breast cancer mortality persists after long-term follow-up," the authors, led by Lennarth Nystrom of Umeaa University, say.

Cancer experts are embroiled in a verbal war over mammography, a low-dose X-ray that can identify small cancers several years before they develop into lumps detectable by the conventional method of palpitation.

Nearly two dozen countries have embarked on major programmes to encourage women to undergo routine mammograms in order to detect any tumour in its earliest possible stages, thus enhancing their chance of survival.

But some opinion says these expensive projects are not providing the hoped-for benefits and may even have negative effects by creating a climate of fear.

The fierce debate has prompted the American Society for Clinical Oncology and an important data group that provides information for the US National Cancer Institute to carry out a review of the evidence.

Nystrom's group says the four Swedish trials, which have already been published separately, provide the best confirmation so far that mammograms are useful, because they give a long-term picture, stretching over years.

Karen Gelmon, of the British Columbia Cancer Agency in Vancouver, said the 21-percent reduction was "statistically significant" and that women who are otherwise well, especially those aged 55-69, should be encouraged to have a mammogram every two years.

But whether the investment presented good value was another matter.

Money could be spent more usefully in fighting other causes of premature death among women, she implied.

"As breast cancer accounts for only about four percent of all deaths annually, even a 21-percent reduction... is barely measurable when all-cause mortality is the endpoint."

Breast cancer and ovarian cancer have been dubbed women's "silent killers" because they are so often diagnosed too late.

The number of women dying from breast cancer in the United States has declined by nearly 30 percent since 1990, but it is unclear whether this is due to the success of awareness campaigns, better diagnostic equipment or better treatment.