Older women with breast cancer are less likely to initiate adjuvant hormonal therapy if they are frail, according to researchers.
In a prospective cohort study of women aged 65 and older diagnosed with invasive, nonmetastatic estrogen receptor–positive breast cancers (n = 1,062), about a quarter of the women were frail or prefrail (4.9% and 18.7%, respectively) based on a validated frailty score determined at baseline, reported Vanessa Sheppard, Ph.D., of Georgetown University Medical Center, Washington (J. Clin. Oncol. 2014 June 16 [doi:10.1200/JCO.2013.51.7367]).
Overall, 14% of the women in the study did not initiate hormonal therapy. Women considered prefrail or frail were significantly less likely to initiate therapy than were those considered "robust" or nonfrail (odds ratio, 1.63; 95% CI, 1.11-2.40; P =.013). Nonwhite race was also significantly associated with noninitiation of therapy (OR, 1.71; CI, 1.04-2.80; P = 0.33).
Baseline frailty was not predictive of discontinuation of therapy after a median follow-up of 3 years, Dr. Sheppard and colleagues reported.
The findings suggest "women and/or their providers are making informed judgments about the risks and benefits," the researchers wrote. "An alternative explanation is that women with greater frailty may have been concerned about adverse effects based on interactions of hormonal therapy and specific comorbidities, such as cardio- and/or cerebrovascular disease and risk of thromboembolic events," they added.
Limitations of the study include a potential for bias associated with self-reporting (discontinuation of therapy was measured only through self-report) and measurement of frailty only at baseline, the investigators said.
The National Institutes of Health, Amgen, and the Cancer and Leukemia Group B (CALGB) Foundation funded the study. Four of Dr. Sheppard’s coauthors, Dr. Gretchen Kimmick, Dr. Eric Winer, Dr. Arti Hurria, and Dr. Claudine Isaacs reported ties with pharmaceutical manufacturers.