A new study has reported that women 75 and older are not seeing the same gains in survival after a diagnosis of breast cancer as women under 75. The study was designed to investigate whether death rates have declined similarly for old and younger women diagnosed with breast cancer. Women 75 and older comprise 40,000 breast cancers each year and are a rapidly growing U.S. demographic group. In the study, the authors examined two outcomes: (1) the rate of breast cancer-specific death in the general population; and (2) the risk of breast cancer-specific death in newly diagnosed patients. Changes in these outcomes over time were compared for older compared to younger women. To conduct the study, the authors used 1990-2007 data from National Vital Statistics Reports and Prevention, published by the Centers for Disease Control, and 1980-1997 data from The Surveillance, Epidemiology, and End Results (SEER) data, complied by the National Cancer Institute. The SEER analysis included 219,024 women ages 20 and older.
Compared to 1990, the rate of breast cancer death was found to decline by 2.5% per year among women aged 20 to 49 years, 2.1% per year for women aged 50 to 64, 2.0% per year for women aged 65 to 74, and 1.1% per year for women 75 and older through 2007. From 1980 to 1997, the adjusted risk of breast cancer-specific death for newly diagnosed patients fell by 3.6% per year for women under 75 years of age compared to a 1.3% annual decline for women 75 years and older. Over the 1980-1997 time period, the 10-year absolute risk of breast cancer-specific death declined by 15.3% (from 31.9% to 16.6%) among breast cancer patients aged 50 to 64. However, the decline was only 7.5% (from 24.8% to 17.4%) for women aged at least 75 years at diagnosis. The data also indicated that African-American breast cancer patients are not experiencing the same improvements in outcomes, as shown by a death rate in 2006 that was 38% higher than that of white women. The authors conclude that breast cancer outcomes have preferentially improved in women aged less than 75 years. Focused research is needed to improve outcomes in older women.
In a separate interview, lead author Benjamin Smith, assistant professor in MD Anderson's Department of Radiation Oncology, said, "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." He further commented that outcomes have improved more rapidly for younger women despite the fact that they have a larger proportion of biologically aggressive disease than older women, who are more likely to have less lethal estrogen receptor positive tumors. This suggests that differences in outcomes may result from suboptimal treatment rather than tumor biology. "We really need to focus research exclusively on developing optimal treatments for older women with breast cancer, evaluating how we can predict which older women can tolerate treatments, and develop new treatments that work better," Smith said.
Please see our article on breast cancer in old age for more information.