The National Cancer Institute (NCI) recently announced that the
breast cancer death rate in American women continued to decline
through 1993. This finding suggests, says NCI, that improved breast
cancer management, from early detection to treatment, is having
a beneficial effect.
Breast cancer mortality trends for US white women have improved
markedly in the 1990s compared with the 1980s. For black women,
increases in mortality persist, especially among older women,
but the overall increase has slowed significantly.
During the most recent 5-year period of available data, 1989 to
1993, age-adjusted breast cancer mortality fell approximately
6% in white women and rose about 1% in black women. By comparison,
from 1980 to 1989, rates increased 3% in white women and 16% in
black women, according to data from the National Center for Health
"These findings are good news, but not good enough,"
said US Department of Health and Human Services (HHS) Secretary
Donna E. Shalala.
"The data suggest the trend is starting to move in a positive
direction for African-American women as well as white women. Rates
have declined among younger black women, although they are still
higher than those of white women and are improving more slowly,"
NCI Director Richard Klausner, MD, said.
The overall death rate from breast cancer in US women has fallen
about 5% in recent years, dropping from 27.5 per 100,000 women
in 1989 to 25.9 per 100, 000 in 1993. This year, an estimated
44,300 women will die of the disease nationwide, but that estimate
could prove to be too high if the trend continues.
In both white and black women, the greatest improvements in mortality
during the recent 5-year period were seen in younger age groups,
but the changes were more modest in blacks than in whites of all
ages. Other mortality trends were also seen:
- Among white women, death rates declined for all decades of
age from 30 to 79 years.
- Among black women, rates were down for all decades from 30
to 69 years.
- For women age 30 to 39 years, rates dropped about 13% in whites
and 5% in blacks.
- For women age 40 to 49 years, rates dropped 9% in whites and
2% in blacks.
- For women age 50 to 59 years, rates declined 9% in whites
and less than 1% in blacks.
- For women 60 to 69 years old, rates decreased 6% in whites
and less than 1% in blacks.
- For women 70 to 79 years old, rates increased 5% in blacks
and decreased 3% in whites.
- For women 80 years and older, rates increased 5% in blacks
and 2% in whites.
The median age at death is 68 years for white breast cancer patients
and 62 years for black breast cancer patients.
Earlier Detection, Improved Treatment
Experts believe the recent decline in breast cancer mortality
is partly a result of mammography screening, which rapidly increased
in the United States during the 1980s and resulted in a shift
toward the detection of breast cancer at earlier, more curable
stages. But they say screening cannot explain all of the decline.
"Such changes in mortality trends across a wide age range
usually indicate improvements in medical interventions, and examination
of stage-specific breast cancer incidence rates and survival rates
suggests that both earlier detection and improved treatment are
likely contributing to the recent declines in breast cancer mortality,"
said Robert Tarone, PhD, of the NCI's Biostatistics Branch.
"Further study is required to determine the relative contribution
of early detection and improved treatment to the recent declines
in breast cancer mortality," added Brenda K. Edwards, PhD,
director of NCI's Cancer Control Research Program. "Research
is now under way to investigate the impact of adjuvant therapy
on mortality rates."
Health authorities in the United Kingdom have also reported a
steep decline in the breast cancer death rate among women age
55 to 69 during roughly the same time period. Mortality in this
group dropped 12% from 1987 to 1994. This trend began at the same
time as the introduction of the UK breast screening program, but
researchers there have concluded that it occurred too soon to
be entirely a result of screening. Instead, they attribute much
of the decline to more effective treatment, particularly the widespread
adoption of tamoxifen (Nolvadex) therapy. These results add weight
to the evidence for a similar beneficial effect of treatment advances
on breast cancer mortality in US women according to the NCI statement.
Racial/Ethnic Differences in Mortality
Breast cancer death rates vary fairly widely among racial and
ethnic groups in the United States. Hispanic, Chinese, Filipino,
and Japanese women have annual rates at or below 15 per 100,000
population, while black, white, and Native Hawaiian women have
rates above 25 per 100,000.
Edwards said the racial differences in mortality depend on several
factors, including the risk of developing breast cancer, access
to screening, and early detection, treatment and medical follow-up,
and supportive care. The NCI is investigating differential risk
factors, pattern of care, and clinical and biologic prognostic
factors for survival, she said, adding that "understanding
of these relationships is still incomplete."
The continued rise in breast cancer mortality in older women extends
a long-standing, trend of increasing breast cancer risk for women
born from 1900 to 1920, Tarone said. Researchers believe the increasing
mortality in this group reflects changes in various risk factors,
such as delayed childbearing early in the century.
Less well-understood is the declining mortality among women under
age 40, who generally are not screened. The trend in this group
appears to reflect a recent change in risk factors above and beyond
the improvements due to medical intervention.
HHS-Sponsored Research Programs
HHS support for breast cancer research, prevention, and treatment
has increased from $271 million in 1993 to $476 million in 1996.
Special programs include:
- a comprehensive effort by the NCI to identify the genetic
and biologic basis of breast cancer, characterize patterns of
risk in the population, and apply the knowledge gained through
basic research to more effective prevention and treatment strategies;
- the CDC's National Breast and Cervical Cancer Early Detection
program, which offers free or low-cost mammography to uninsured
or low-income women;
- the FDA's quality standards for mammography services; and
- the clinical practice guidelines on mammography issued by
the Agency for Health Care Policy and Research.
In addition, the Health Care Financing Administration of the HHS
helps pay for mammography for beneficiaries of the Medicare program.
In recent years, some 37% of women beneficiaries have been making
use of Medicare's mammography coverage. An ongoing HHS campaign,
targeted especially at women over age 65, aims to increase the
use of the benefit to at least 60% by the year 2000.