Older women with breast cancer may be at greater risk than younger women of dying from the disease, regardless of the type of tumor they have or treatment they undergo, according to a study released Tuesday.
The study, published in the Journal of the American Medical Association, suggests that women's age may play a larger role in risk of death from breast cancer than previously believed.
Researchers in the Netherlands analyzed the data from more than 9,000 women with hormone receptor-positive breast cancer who'd been enrolled in a five-year randomized clinical trial, during which 1,043 women died.
The researchers found the risk of dying from breast cancer in women age 75 or older was about 8 percent compared with around 6 percent for women younger than 65 and in women between the age of 65 to 74.
Nearly 300,000 women were diagnosed with breast cancer in 2011, according to the National Cancer Institute. Older postmenopausal women are at highest risk for breast cancer recurrence.
"Because breast cancer incidence increases with increasing age, changing demographics and continuously increasing life expectancy will further enlarge the number of older women confronted with breast cancer," the researchers wrote.
Larger tumors were found in older women than in younger women at the time of diagnosis, which may have contributed to their increased risk of death, the researchers noted.
"Typically, women who are older get less aggressive cancers, but this shows you can't discount aggressive diseases in older women," said Dr. Deborah Axelrod, director of clinical breast services and breast surgery at NYU Langone Medical Center.
There are many factors that may contribute to an older woman's increased risk of breast cancer death, Axelrod said.
Previous studies suggested that older postmenopausal women were less likely to receive standard chemotherapy and radiation compared with younger women.
But older women were also more likely to be treated overtreated with medications -- known among physicians as polypharmacy -- which puts them at higher risk to respond poorly to treatment. But researchers said this was not a contributing factor in their findings.
The women in all age groups of the study were generally healthier, because they'd received adequate hormone therapy, according to the study methods.
"So if you're finding an increased risk in this population, what are we saying about the general population of women?" said Axelrod.
The findings lend themselves to future studies on older women with breast cancer and what exactly causes higher risk of death with age, she said.