WASHINGTON -- The decades-long rise in the rate of new breast cancer cases in American women appears to have leveled off, indicating that the nation may have reached a long-sought turning point in the battle against the malignancy.
After climbing steadily since 1980, the breast cancer rate stopped rising in 2001 and may have started to fall in 2003, according to the latest federal data. It will take years before it becomes clear whether the change marks the start of a trend, but the statistics appear to indicate a tantalizing shift, specialists said.
``I think we're finally beginning to see a change -- that it's leveling off -- and we may even be seeing the start of a decline," said Brenda Edwards of the National Cancer Institute, who led a team that reported the change in an annual report on cancer released yesterday. ``We have to be cautious. But I think it's real."
The new report did not examine why the number of breast cancer cases would have plateaued, but Edwards and others said it could be because of a combination of factors: the use of mammography appears to have peaked, the number of women delaying childbearing may have stabilized, and the use of hormones after menopause has plummeted.
``These are just some hypotheses. There may be other factors we don't know about," said Ahmedin Jemal of the American Cancer Society, who helped prepare the analysis of data collected by cancer registries throughout the country. ``Breast cancer is influenced by many factors. It's very complex."
Although the death rate from breast cancer has been declining because of earlier diagnosis and improved treatment, the new numbers mark the first sign the number of women getting breast cancer may have stopped increasing.
Whatever the cause, that would mark a milestone with major public health implications because of the large number of women diagnosed with the disease. Nearly 213,000 women find out they have breast cancer, and nearly 41,000 die of the disease each year, making it the most common cancer in women and the second-leading cancer killer after lung cancer.
``The fact that it's the most frequently diagnosed cancer in women means small changes in statistics have a substantial impact on a large number of women," Edwards said. ``Even a small decrease or change would represent a fair number of women."
``It's good news, very happy news," said Nancy E. Davidson, who directs the Breast Cancer Center at Johns Hopkins University in Baltimore. ``We've been concerned because breast cancer has been rising for some time. The notion that it's plateauing is very good news."
Some advocates, however, expressed doubt about the numbers, saying cancer reporting is highly unreliable.
``I don't trust the accuracy of these numbers," said Barbara Brenner of Breast Cancer Action, an advocacy group based in San Francisco . ``There's still way too many women getting breast cancer."
Other specialists, while less skeptical that the rate had leveled off, also expressed caution.
``It's too soon to know whether we're turning the tide," said Carolina Hinestrosa of the National Breast Cancer Coalition.
The number of women being diagnosed with breast cancer began rising in 1980 . Although the rate slowed in the 1990s, it continued a slow but steady rise throughout the decade.
In 2001 that trend line appears to have finally hit a plateau, according to the Annual Report to the Nation on Cancer, which is prepared by the Cancer Institute, the American Cancer Society, the North American Association of Central Cancer Registries, and the Centers for Disease Control and Prevention.
The rate at which women were diagnosed with breast cancer fell from 137.3 per 100,000 in 2001 to 133.8 in 2002, in statistical terms essentially no change, but then fell to 124.2 in 2003, a significant drop.
Researchers are eagerly awaiting the first analysis of the 2004 numbers, which are just starting to come in.
Edwards speculated that the number might tick back up slightly, in part because there may have been some underreporting in 2003.