The introduction of a National Health Service breast screening program, along with improvements in treatment for breast cancer, led to a 21 percent reduction in breast cancer deaths in England and Wales between 1990 and 1998, according to a study in this week's "British Medical Journal."

Using national data on breast cancer deaths for 1971-'89, Roger Blanks, Ph.D., and colleagues were able to predict the number of deaths for 1990-'98. The effect of screening and other factors on breast cancer deaths during this period then was estimated by comparing observed deaths with those predicted among women aged 50-54 and 75-79, the effect of screening being restricted to certain age groups.

In 1998, estimated deaths from breast cancer were 21 percent below that predicted in the absence of screening or other effects in women aged 55-69, the research found. Of this decline, 6 percent to 7 percent was a direct effect of screening — the equivalent of 320 prevented deaths.

Other factors, such as improvements in treatment and presentation of cancers at an earlier stage, also play major roles in the substantial reduction in deaths from breast cancer, the researchers indicated.

The authors also expressed confidence that further effects from screening, together with improved treatment, will result in even more reductions in breast cancer deaths, particularly for women aged 55-69, over the next decade.