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.
However, when it comes to breast cancer death rates, any decrease can be considered a victory. Experts note that even though these rates didn't decrease as quickly for older women, they still are lower than ever, representing a major medical victory of the last three decades.
"Because of historical differences in access to care and early detection, there are persistent disparities in these gains in different groups of women," said Dr. Harold Burstein, a breast oncologist at the Dana Farber Cancer Institute in Boston. "Thus, it is harder to see as much gain in the older patients as it is in the younger ones."
Smith emphasized the importance of medical advances against breast cancerbut said more research should focus on how screening and treatment should be tailored to the needs of older patients.This knowledge may come in handy in the next 20 years. As the population ages, the number of older women with breast cancer is expected to increase by 57 percent.