Breast cancer is the most commonly diagnosed nondermatologic cancer
and the second leading cause of cancer-related deaths among women
in the United States. In 1996, a total of 184,300 new cases of
and 44,300 deaths from invasive breast cancer are projected among
women. To assess trends in incidence and death rates for breast
cancer among US women, the CDC analyzed national incidence data
from the National Cancer Institute's Surveillance, Epidemiology,
and End Results (SEER) program and death-certificate data from
the CDC's National Center for Health Statistics (NCHS).
This report presents incidence and death rates for breast cancer
for 1992 (the most recent year for which SEER data were available)
and summarizes trends in these rates for 1973 to 1992. Overall,
these findings indicate that incidence rates for invasive breast
cancer increased among women during 1973 to 1987 and stabilized
during 1988 to 1992, while mortality remained stable during 1973
to 1988 and decreased during 1989 to 1992.
The incidence rate of breast cancer in the United States is estimated
by using aggregate data reported by the SEER program, which includes
a nonrandom sample of approximately 14% of the US population.
Based on 1990 data from the Bureau of the Census, the demographic
characteristics of persons included in SEER is representative
of the total US population for whites and blacks; in addition,
persons included in SEER reflect the percentage of persons among
the total US population living below the poverty level* and the
percentage of adults who graduated from high school. However,
a higher proportion of persons included in SEER resided in urban
This analysis includes all cases of invasive breast cancer (International
Classification of Diseases, for Oncology, codes C50.0-C50.9) registered
in SEER. Annual incidence rates were computed for 1973 to 1992,
and race- and age-specific average annual incidence rates were
computed for the combined years of 1988 to 1992.
Decedents for which the underlying cause of death was breast cancer
(International Classification of Diseases, Adapted, Ninth Revision,
codes 174.0-174.9) were identified from public-use mortality data
tapes. Annual death rates were computed for 1973 to 1992, and
race-specific average annual death rates by age and by state were
computed for the combined years of 1988 to 1992.
Denominators for annual incidence and death rate calculations
were derived from US census population estimates. Rates were directly
standardized to the age distribution of the 1970 US population
using 5-year age groupings. Data are presented only for whites
and blacks because numbers for other racial/ethnic groups were
too small for meaningful analysis.
Breast Cancer Incidence
In 1992, the overall age-adjusted incidence rate for breast cancer
was 110.6 per 100,000 women. The rate for white women (113.1)
was higher than that for black women (101.0).
During 1973 to 1992, the overall incidence rate increased from
82.5 to 110.6: rates increased steadily during 1973 to 1987 and
stabilized during 1988 to 1992 (Figure 1). During 1988 to 1992,
incidence rates increased directly with age until age 75 to 79
years for whites and age 80 to 84 years for blacks; the rates
for whites and blacks were similar for women age less than 45
years, but for women age 45 years or more, the rate was higher
for whites than for blacks. During 1973 to 1992, race-specific
rates varied: for white women, the age-adjusted rate increased
34% (from 84.3 to 113.1) and, for black women, increased 47% (from
68.7 to 101.0).
Breast Cancer Mortality
In 1992, a total of 43,063 US women died from breast cancer. The
death rate was 26.2 per 100,000 women.
During 1973 to 1992, the overall death rate varied; rates were
stable during 1973 to 1988, before decreasing during 1989 to 1992
(Figure 1). During 1988 to 1992, the overall ratio of black-to-white
death rates was 1.2. Rates increased directly with age. For women
age less than 70 years, the rate was higher for blacks than for
whites; for women age 70 years or more, the rate was higher for
whites than for blacks. During this period, race-specific rates
varied. During 1989 to 1992, the rate for white women decreased
6% (from 27.5 to 26.0) and, for black women, increased 3% (from
30.4 to 31.2).
During 1988 to 1992, the state-specific age-adjusted death rate
ranged from 18.2 in Hawaii to 35.3 in the District of Columbia.
Editorial Note from the CDC
The findings in this report indicate that incidence rates for
breast cancer increased 34% during 1973 to 1992. The increase
and later stabilization of incidence rates during the 1980s is
most likely related to increased use of breast cancer screening
methods, particularly mammography and clinical breast examination,
which enable earlier diagnosis of the disease.
The decrease in breast cancer death rates during 1989 to 1992
may reflect a combination of factors, including earlier diagnosis
and improved treatment. For example, screening mammography and
clinical breast examination are effective methods for reducing
breast cancer mortality among women age 50 years or more. Survival
from breast cancer increases when the disease is diagnosed at
earlier stages, and from 1974-1976 to 1986-1991, the survival
rate for invasive breast cancer increased substantially.
Differences in the race-specific and state-specific incidence
and death rates for breast cancer during 1973 to 1992 may reflect
differences in such factors as socioeconomic status, access to
and delivery of medical care, and the prevalence of specific risks
for disease. For example, women in minority populations are less
likely than white women to be screened for breast cancer. Although
socioeconomic and risk-factor data were not analyzed in this report,
the findings underscore the need for further characterization
of the burden of cancer for US women in racial/ethnic, geographic,
and other subgroups.
Early detection and appropriate treatment are essential to reducing
the burden of breast cancer in the United States. The CDC's National
Breast and Cervical Cancer Early Detection Program provides early
detection screening and referral services for cancers of the breast
and cervix among older women who have low incomes or are uninsured,
underinsured, or in a racial/ethnic minority. Additional efforts
by this program and health-care professionals are needed to ensure
that every US woman at risk for breast cancer receives breast
cancer screening, prompt follow-up, and assurance that tests are
conducted in accordance with current federal quality standards.
Adapted from Morbidity and Mortality Weekly Report, vol 45, no.
39, October 4, 1996.