Breast Cancer Death Rate Continues to Decline in U.S., Institute Reports

WASHINGTON —  The breast cancer death rate among American women has dropped again, apparently reflecting the effects of early detection and treatment, according to new statistics released Tuesday by the National Cancer Institute.

The decline has been especially pronounced among white women in the 1990s, reversing an upward trend from the previous decade, the institute said. Increases in the death rate have continued for black women but, even in this group, the overall increase has slowed significantly, the NCI said.

The American Cancer Society has estimated that 44,300 women will die of the disease in 1996, “but that estimate could prove to be too high if the trend continues,” the institute said in a statement.

Jane Henehan, an official with the society, said that “nothing would make us happier than to have our death projections proved wrong.”

Breast cancer is the most commonly occurring cancer in women--a projected 184,300 new cases will be diagnosed this year--although lung cancer is the leading cancer killer of women.

From 1989 through 1993, the most recent five-year period of available data, the age-adjusted breast cancer mortality rates declined about 6% among white women and rose about 1% in black women. From 1980 to 1989, rates had increased 3% for whites and 16% for blacks, the NCI said.

“The data suggest [that] the trend is starting to move in a positive direction for African American women as well as white women,” said Dr. Richard Klausner, director of NCI. “Rates have declined among younger black women, although they are still higher than those of white women and are improving more slowly.”

Breast cancer mortality rates vary fairly widely among racial and ethnic groups in the United States. Latino, Chinese, Japanese and Filipino women record annual mortality rates below 15 per 100,000; while white, black and native Hawaiian women have rates higher than 25 per 100,000.

Overall, the breast cancer death rate for U.S. women has fallen about 5% in recent years, dropping from 27.5 per 100,000 women in 1989 to 25.9 in 1993, the institute said.

Health officials said that a rapid increase in mammography during the 1980s could partly account for the good news but does not explain it all. They said that research is underway to evaluate the effect of various breast cancer treatments.

Health authorities in the United Kingdom also have reported a sharp reduction in the breast cancer death rate among women 55 to 69 during roughly the same period, NCI said. The mortality rate in this group dropped 12% from 1987 to 1994, a trend that began at the same time as the United Kingdom introduced its breast screening program.

However, U.K. researchers believe that the decline began too soon to be entirely the result of screening and have attributed it also to more effective therapies, particularly the widespread use of tamoxifen, a drug frequently given after breast cancer surgery to prevent recurrence of the disease, the NCI said.

“These results add weight to the evidence for a similar beneficial effect of treatment advances on breast cancer mortality in U.S. women,” the cancer institute said.

In whites, death rates dropped for all age groups from 30 to 79 years; in blacks, mortality declined for all age groups from 30 to 69.

Continued increases in death rates among the most elderly women--80 and older--extends a long-standing trend in breast cancer risk among women born from 1900 to 1920, NCI said.

Death rates rose 5% for black women older than 80 and 2% for white women in that age group. Researchers said that they believe the increasing rates reflect changes in risk factors, such as delayed child-bearing that occurred early in the century.

In both black and white women in the United States, the largest gains in mortality in the recent five-year period were seen in younger age groups, but the changes were more modest in blacks than in whites of all ages, the institute said.

Racial differences in mortality rates likely were related to several factors, including the risk of developing breast cancer and access to detection and treatment, NCI said.

But health officials said that they could not explain the declining mortality among women younger than 40, who generally are not screened. For women 30 to 39 years old, rates dropped 13% in whites and 5% in blacks.

The trend “appears to reflect a recent change in risk factors above and beyond the improvements due to medical intervention,” NCI said.

In the 40-to-49 age range, rates dropped 9% among whites and 2% among blacks. In white women 50 to 59, the rates declined 9%; in blacks 50 to 59, the decline was less than 1%.

For women 60 to 69, the rates declined 6% in whites and less than 1% in blacks. In women 70 to 79, the rates increased 5% in blacks, while decreasing 3% in whites.