Despite marked advances in breast cancer screening and treatment in the past 30 years, a new study suggests that older women may not be benefiting from these advances as much as younger patients.
Researchers at the MD Anderson Cancer Center in Houston studied reports of patients who died of breast cancer from 1980-2007. In about 1990, U.S. breast cancer death rates began to decrease, and they edged downward each year after that. The rate of breast cancer death decreased by 2.5 percent each year for women between the ages of 20 and 49, and roughly 2 percent for women between the ages of 50 and 74, but only 1.1 percent each year among women over age 75.
The study also reported that the breast cancer death rate among black women is 38 percent higher than that of white women, confirming previous research about how the disease differs with respect to race.
A woman's risk of getting breast cancer generally increases with age, and women over age 75 account for nearly 40,000 cases of breast cancer each year in the U.S. But Dr. Ben Smith, a radiation oncologist and the study's lead author, said doctors often view and treat the disease differently in older women.
"Generally, we think of breast cancer in older women as being a little less aggressive, and treatments tend to be less aggressive for these women," Smith said. "When you put all of that together, improvements in breast cancer treatment in older women are lagging behind."
According to the study, the reasons for these differences may come from three areas: screening, treatment and research.
Although the U.S. Preventive Services Task Force recommends a mammogram every two years for women ages 50 to 74, the panel stops short of recommending mammograms for women over age 75, citing insufficient data to show real benefits or harm in screening older women. Smith said a drop in screening may result in a missed opportunity to catch breast cancer in its early stages in older women, creating more lethal forms of the disease.
When it comes to treatment, advanced age can be a complication. Powerful doses of chemotherapy drugs are generally more toxic and less well-tolerated in older people, who often have more chronic conditions that affect their treatment. As a result, Smith said many doctors tend to steer clear of taking these aggressive approaches for their older patients.
Additionally, age-related chronic conditions often keep older people out of clinical trials that study new treatments, creating a dearth of knowledge of how best to treat older breast cancer patients.
"Most of the research so far has focused on improving outcomes in younger women with breast cancer," Smith said. "Our historic inattention to the older age group has resulted in older women not really reaping the benefits of treatment advances as younger women have."
Experts agree that more research is needed on how to keep older patients from dying of breast cancer. But in studying deaths related to the disease, pinpointing breast cancer as a specific cause of death in these patients can be difficult.
"If a woman dies at 80 and she has metastatic disease and pneumonia, did she die from metastatic breast cancer or the pneumonia?" said Dr. Charles Shapiro, director of breast medical oncology at the Ohio State University Comprehensive Cancer Center, who said that causes of death listed on death certificates, which Smith and his colleagues used in their analysis, can be unreliable.