A falling rate, a rising death toll
Breast cancer mortality among U.S. adults aged 65 and older fell over the 1999-2020 period when measured as an age-adjusted rate, but the annual death toll moved in the opposite direction. The overall rate declined from 71.58 deaths per 100,000 people in 1999 to 50.83 in 2020. Annual deaths rose from 24,760 to 27,409. Across the full period, the average annual percentage change was a 1.64% decline.
The study used aggregate CDC WONDER death-certificate data rather than following a defined group of individuals. It counted breast cancer when it was recorded as the underlying cause of death, using ICD-10 code C50, and excluded deaths in which breast cancer appeared only as a contributing condition. For rate estimates, researchers directly standardized rates to the 2000 U.S. standard population across ages 65-74, 75-84, and 85 or older.
The decline was clearest in the first part of the record. From 1999 to 2014, the rate fell 1.871% per year, a statistically significant change. From 2014 to 2020, the estimated decline slowed to 1.061% per year and was not statistically significant, with P = 0.074. The study used P < 0.05 as its threshold for statistical significance, so the later segment indicates a possible slowdown rather than a confirmed change in direction.
The burden rose with age and fell unevenly
Women carried almost all of the recorded burden. Of 544,812 breast cancer deaths across the period, 538,489 were among women and 6,323 among men. The pooled female-specific age-adjusted mortality rate was 99.84 per 100,000 women, compared with 1.70 per 100,000 men.
Within 2020, the crude mortality rate increased steadily with age: 33.03 per 100,000 among adults aged 65-74, 55.89 among those aged 75-84, and 112.10 among those 85 or older. Rates were higher among women than men. These are age-specific crude estimates, not the age-adjusted rates used for the long-term comparison.
Differences between groups and places
The study also found differences between groups. Female-specific mortality was highest among Black or African American women and lowest among Asian or Pacific Islander women. Non-Hispanic older women had higher rates than Hispanic older women. Rates were highest in the Midwest and Northeast and lower in the South and West. Metropolitan and nonmetropolitan rates were broadly comparable.
State-level comparisons showed a similarly wide spread. In the primary female analysis, the age-adjusted mortality rate ranged from 65.95 per 100,000 women in Hawaii to 123.03 in the District of Columbia. These comparisons are descriptive: they show how rates differed across jurisdictions, but not what produced the gap.
Researchers also compared state-level mortality with the Socio-Demographic Index, or SDI. Across pooled jurisdiction-year observations, SDI and mortality had a modest inverse rank correlation, meaning the combined observations tended to show higher SDI alongside lower mortality. But after controlling for each jurisdiction and calendar year, increases in SDI were associated with higher age-adjusted mortality within jurisdictions. The authors treated this split result as ecological and noncausal, not as evidence that SDI itself changed mortality.
A separate 2020 frontier analysis estimated a descriptive lower boundary across 50 jurisdictions. The five smallest gaps included Hawaii, at 17.24 deaths per 100,000 women, while the five largest included Wyoming, at 62.62. The researchers did not present these gaps as preventable mortality estimates or causal effects.
What the numbers cannot explain
The findings map a population pattern through 2020, not an explanation for it. The ecological panel and frontier analyses compare jurisdictions rather than individuals, so they cannot establish individual-level or causal effects or identify the mechanisms behind geographic mortality patterns. The data show where mortality was higher, lower, falling, or changing more slowly, but not why those patterns occurred.
Paper data and sources
Original title: Trends and disparities in breast cancer mortality among older adults in the United States, 1999–2020
Authors: Feng T, Zheng P, Li Q et al.
Journal/Repository: Frontiers in oncology
Status: Peer-reviewed
First online: 2026-10-10
DOI: Not available
Original paper · Full text