Population-based breast cancer mortality rates in the UK have fallen steeply in the last two decades - more than in any other major European country, finds a study published in the BMJ online on Wednesday. These results challenge claims that survival after breast cancer is worse in the UK than elsewhere in western Europe.

The apparently poor UK survival rates are misleading because of shortcomings in the way cancers are registered in the UK, whereas the population-based mortality rates are reasonably reliable, says an accompanying editorial.

Since the late 1980s, breast cancer mortality rates have been falling in many European countries. This has been largely attributed to the combined effects of early diagnosis, including breast screening, and the effective treatment of breast cancer.

A team of researchers led by Philippe Autier from the International Prevention Research Institute in France, examined changes in breast cancer mortality rates in women living in 30 European countries from 1980 to 2006.

Using World Health Organisation data, mortality rates were calculated for all women and by age group (less than 50 years, 50-69 years and 70 years and over).

From 1989 to 2006, breast cancer mortality decreased by 20% or more in 15 European countries. In the UK, mortality rates fell by about 30%, more than in any other major European country. In France, Finland and Sweden, that have also invested much in breast screening and new cancer drugs, mortality rates decreased by 10-16%.

In central European countries, breast cancer mortality rates did not decline and even increased during the last two decades.

Women aged under 50 showed the biggest reductions in mortality rates, although screening at that age is uncommon. This may reflect better targeting of effective treatments, suggest the authors. They also suggest that the sustained decline observed in many countries seems to indicate that breast cancer mortality will continue to decrease beyond 2006.

The authors call for better data collection to help understand the variations in breast cancer mortality across Europe and action to reduce avoidable breast cancer mortality in central European countries.

In an accompanying editorial, Valerie Beral and Richard Peto, at the University of Oxford, point out that cancer registration in the UK is known to be incomplete and that defects in these data make cancer survival rates appear significantly worse than they really are. By contrast, the registration of death is complete, deaths from breast cancer are well recorded (except at old age), and so population-based mortality trends in middle age are fairly reliable.

They conclude that the rapid decline in UK population-based breast cancer mortality rates in middle age (see graph - link below) are valid and that failure to make proper allowances for the shortcomings of cancer registration data "may well have led to misleading claims about the supposed inferiority of UK cancer treatment services in general."

Source: British Medical Journal