U.S. Breast Cancer Mortality Drops 20% in the 1990s.

Credit given to improvements in public awareness, chemotherapy, tamoxifen.

SAN ANTONIO -- The unprecedented 20% national declines in breast cancer mortality during the 1990s were due to a series of modest additive improvements in therapy rather than a major breakthrough, according to the latest analysis of the Early Breast Cancer Trialists' Collaborative Group.

"It's not only one thing. It's a bit of this and a bit of that. We must not underestimate the importance of moderate benefits: a 3% gain in survival, a 5% gain in survival. You add up a few threes and fives and you finish up with quite a large gain," Sir Richard Peto, Ph.D., explained in sharing unpublished Early Breast Cancer Trialists' Collaborative Group (EBCTCG) data involving 200,000 women with breast cancer.

The recent sharp improvement in breast cancer survival can be credited to a combination of systematic screening programs, increased public awareness of the disease, earlier surgery improved methods of achieving local control, more effective chemotherapy tamoxifen, ovarian ablation, and advances in radiation therapy he said at a breast cancer symposium sponsored by the San Antonio Cancer Institute.

These achievements are all the more impressive because they occurred despite an increase in the actual incidence of the disease. They also bucked the historical worldwide trend for rising breast cancer mortality during periods of affluence, noted Dr. Peto, professor of medical statistics and epidemiology at the University of Oxford (England).

And the best is yet to come. Survival gains documented in the 1990s were the result of changes in clinical practice introduced in the 1980s. There is every reason to think that with the further moderate improvements in practice brought to bear in the 1990s, the risk of death in women presenting with early breast cancer today will prove to be approximately half that of women who presented in 1980, Dr. Peto predicted.

For the last 15 years, breast cancer investigators have collaborated in a fashion that's the envy of the rest of the scientific world. This fall they met at Oxford to generate one of their periodic EBCTCG metaanalyses. This latest one is based upon new follow-up data from 300 randomized controlled trials involving 200,000 women with breast cancer, of whom 60,000 to date have died from the disease. It takes numbers on this massive scale to reliably identify small but worthwhile survival advantages, Dr. Peto stressed.