Except for frail patients, most participants in the large study complied with their oncologists' recommendations to treat their estrogen-positive breast cancer with hormone therapy — either an aromatase inhibitor or tamoxifen. These drugs prevent tumors from using estrogen to fuel growth.
But the study, reported online June 16th in the Journal of Clinical Oncology
, also found that non-white women were much more likely to not have therapy.
"Women 65 years of age and older comprise about half of patients with breast cancer, but some studies have suggested this group initiates therapy less often and discontinues treatment more frequently than younger or middle aged women," says the study's lead author, Vanessa B. Sheppard, PhD, associate professor of oncology and assistant director of health disparities research at Georgetown Lombardi Comprehensive Cancer Center.
"We found a more positive picture of use — although more than half of patients discontinued use before the five years of recommended treatment, non-initiation of starting treatment was only 14 percent," she says. "This is reassuring, as it's important for women to give themselves a chance for the best outcome possible, regardless of their age."The seven-year study was conducted at 78 institutions and clinics in the U.S., enrolling 1,062 elderly women ages 65 to 91 with locally invasive cancer that had not spread.Women in the study judged to be frail or even "prefrail" may well be justified in not starting treatment for their breast cancer compare to women who are more robust or less frail, she says.
"It may be that these women, with the concurrence of their physicians, felt they would not live long enough to benefit from the therapy given competing health conditions, and they also may have wanted to avoid any toxicities from treatment," Dr. Sheppard says. Researchers also found that the discontinuation rate (stopping therapy before five years) was 51.5 percent and that the risk of discontinuation was higher with increasing age and lower for advanced stages of the disease. "This rate of discontinuation is about the same seen in some other studies," she says.