SAN DIEGO — Breast cancer survivors are taking an average of eight medications or supplements, results from a survey of nearly 400 women showed.
“This study shows that there is a need to evaluate medications women are taking prior to the start of cancer treatment to promote discussion and education about drug-drug interactions that can impact treatment,” Julie L. Otte, Ph.D., said in an interview after her poster presentation at the annual meeting of the North American Menopause Society.
To date, the majority of research in the medical literature has focused on diseases and medications that are related to the prevalence of cancer, said Dr. Otte, a nurse who is a postdoctoral fellow focussing on behavioral oncology at Indiana University School of Nursing, Indianapolis. “However, there is little research in the field of pharmacogenetics regarding drug-drug interactions and cancer treatment and survivorship,” she said.
To investigate the association, she and her associates reviewed prescription, herbal, and over-the-counter medications reported in baseline questionnaire data from the COBRA (Consortium on Breast Cancer Pharmacogenomics) randomized clinical trial that evaluated the pharmacogenetics and toxicities of exemestane and letrozole for the treatment of breast cancer. The sample included 389 female breast cancer survivors with a mean age of 59 years and a mean body mass index of 37 kg/m
The top five noncancer comorbid conditions reported by the study participants were drug allergies (50%), high or low blood pressure (41%), high cholesterol (38%), a history of bone fracture (34%), and arthritis (29%).
The women reported that they were taking an average of eight medications or supplements per day. The five most common therapeutic categories represented were vitamins and herbal supplements (39%), cardiac drugs (16%), medications for pain and inflammation (13%), other (9%), and drugs for psychological conditions (6%).
“Although we expected the number of comorbid conditions to increase with age, requiring several prescription medications, it was interesting that the majority of medications reported were over-the-counter” herbals or supplements, and not prescriptions, Dr. Otte commented. Because these data were collected before the patients started a clinical trial, it is unclear whether patients would divulge the same information to their practitioners who prescribe routine medications. The extent of polypharmacy and the number of practitioners prescribing medications are also unclear.
“All of these questions prompt the need for further investigation and study to better educate patients on the possible harm of certain drug interactions,” Dr. Otte said. She said the study had certain limitations, including the potential for underreporting of prescription and over-the-counter medications by some participants. “In addition, it is unclear if these results can be generalized to a noncancer population of women or other cancer populations.” Dr. Otte reported that she had no conflicts of interest related to the study, which was funded by the National Cancer Institute.