NCI Reports Improvement in Breast Cancer Death Rate

Oncology, ONCOLOGY Vol 10 No 6, Volume 10, Issue 6

The National Cancer Institute (NCI) recently announced that the breast cancer death rate in American women continued to decline through 1993.

The National Cancer Institute (NCI) recently announced that thebreast cancer death rate in American women continued to declinethrough 1993. This finding suggests, says NCI, that improved breastcancer management, from early detection to treatment, is havinga beneficial effect.

Breast cancer mortality trends for US white women have improvedmarkedly 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 to1993, age-adjusted breast cancer mortality fell approximately6% in white women and rose about 1% in black women. By comparison,from 1980 to 1989, rates increased 3% in white women and 16% inblack women, according to data from the National Center for HealthStatistics.

"These findings are good news, but not good enough,"said US Department of Health and Human Services (HHS) SecretaryDonna E. Shalala.

"The data suggest the trend is starting to move in a positivedirection for African-American women as well as white women. Rateshave declined among younger black women, although they are stillhigher 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 fallenabout 5% in recent years, dropping from 27.5 per 100,000 womenin 1989 to 25.9 per 100, 000 in 1993. This year, an estimated44,300 women will die of the disease nationwide, but that estimatecould prove to be too high if the trend continues.

In both white and black women, the greatest improvements in mortalityduring the recent 5-year period were seen in younger age groups,but the changes were more modest in blacks than in whites of allages. Other mortality trends were also seen:

  • Among white women, death rates declined for all decades ofage from 30 to 79 years.
  • Among black women, rates were down for all decades from 30to 69 years.
  • For women age 30 to 39 years, rates dropped about 13% in whitesand 5% in blacks.
  • For women age 40 to 49 years, rates dropped 9% in whites and2% in blacks.
  • For women age 50 to 59 years, rates declined 9% in whitesand less than 1% in blacks.
  • For women 60 to 69 years old, rates decreased 6% in whitesand less than 1% in blacks.
  • For women 70 to 79 years old, rates increased 5% in blacksand decreased 3% in whites.
  • For women 80 years and older, rates increased 5% in blacksand 2% in whites.

The median age at death is 68 years for white breast cancer patientsand 62 years for black breast cancer patients.

Earlier Detection, Improved Treatment

Experts believe the recent decline in breast cancer mortalityis partly a result of mammography screening, which rapidly increasedin the United States during the 1980s and resulted in a shifttoward the detection of breast cancer at earlier, more curablestages. But they say screening cannot explain all of the decline.

"Such changes in mortality trends across a wide age rangeusually indicate improvements in medical interventions, and examinationof stage-specific breast cancer incidence rates and survival ratessuggests that both earlier detection and improved treatment arelikely 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 contributionof early detection and improved treatment to the recent declinesin breast cancer mortality," added Brenda K. Edwards, PhD,director of NCI's Cancer Control Research Program. "Researchis now under way to investigate the impact of adjuvant therapyon mortality rates."

Health authorities in the United Kingdom have also reported asteep decline in the breast cancer death rate among women age55 to 69 during roughly the same time period. Mortality in thisgroup dropped 12% from 1987 to 1994. This trend began at the sametime as the introduction of the UK breast screening program, butresearchers there have concluded that it occurred too soon tobe entirely a result of screening. Instead, they attribute muchof the decline to more effective treatment, particularly the widespreadadoption of tamoxifen (Nolvadex) therapy. These results add weightto the evidence for a similar beneficial effect of treatment advanceson 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 andethnic groups in the United States. Hispanic, Chinese, Filipino,and Japanese women have annual rates at or below 15 per 100,000population, while black, white, and Native Hawaiian women haverates above 25 per 100,000.

Edwards said the racial differences in mortality depend on severalfactors, including the risk of developing breast cancer, accessto screening, and early detection, treatment and medical follow-up,and supportive care. The NCI is investigating differential riskfactors, pattern of care, and clinical and biologic prognosticfactors for survival, she said, adding that "understandingof these relationships is still incomplete."

The continued rise in breast cancer mortality in older women extendsa long-standing, trend of increasing breast cancer risk for womenborn from 1900 to 1920, Tarone said. Researchers believe the increasingmortality 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 underage 40, who generally are not screened. The trend in this groupappears to reflect a recent change in risk factors above and beyondthe improvements due to medical intervention.

HHS-Sponsored Research Programs

HHS support for breast cancer research, prevention, and treatmenthas increased from $271 million in 1993 to $476 million in 1996.Special programs include:

  • a comprehensive effort by the NCI to identify the geneticand biologic basis of breast cancer, characterize patterns ofrisk in the population, and apply the knowledge gained throughbasic research to more effective prevention and treatment strategies;
  • the CDC's National Breast and Cervical Cancer Early Detectionprogram, which offers free or low-cost mammography to uninsuredor low-income women;
  • the FDA's quality standards for mammography services; and
  • the clinical practice guidelines on mammography issued bythe Agency for Health Care Policy and Research.

In addition, the Health Care Financing Administration of the HHShelps pay for mammography for beneficiaries of the Medicare program.In recent years, some 37% of women beneficiaries have been makinguse of Medicare's mammography coverage. An ongoing HHS campaign,targeted especially at women over age 65, aims to increase theuse of the benefit to at least 60% by the year 2000.