The researchers also looked at the risk of breast cancer death. In 1980-1984, women ages 75 and older had the lowest risk of 10-year breast cancer death, 24 percent. In contrast, those younger than 75 had 10-year breast cancer risk that ranged from 29 percent to 31 percent. By 1995-1997, the risk for women ages 75 and older was 17.3 percent, compared to younger women who ranged from 15.4 percent to 16.6 percent.
Additionally, the study determined that black women with breast cancer are not seeing improvements in outcomes, evidenced by an absolute death rate in 2006 that was 38 percent higher than whites.
"We found that the oldest women, regardless of their race, and blacks, regardless of their age, are not benefiting as much from improvements in breast cancer treatments," Smith said.
Interestingly, explained Smith, less lethal estrogen receptor positive cancers are more common in older women, yet outcomes have still improved more rapidly for younger women who have a larger proportion of biologically aggressive disease. This suggests outcomes may be tied to suboptimal treatment rather than tumor biology.
While the study didn't examine root causes, Smith said several factors may account for the findings, including: the lowest mammography rates for older women; limited knowledge of optimal treatment resulting from under-representation or exclusion in clinical trials; and chemotherapy toxicity, which limits the ability to deliver therapy at recommended dosages.
|Contact: William Fitzgerald|
University of Texas M. D. Anderson Cancer Center