Medication use in breast cancer survivors compared to midlife women.

Purpose: Many breast cancer survivors (BCS) take multiple medications for health problems associated with the treated cancer and other noncancer comorbidities. However, there is no published, large-scale descriptive evaluation of medication use in BCS compared to midlife women. The purpose of this study was (1) to compare the number and types of prescription medications and over-the-counter medications between BCS and midlife women without cancer and (2) to assess possible drug-drug interactions by evaluating the cytochrome P450 isoform properties of medications (inductors and inhibitors) in both groups.

Methods: A cross-sectional, descriptive, comparative design was used. Baseline data from 98 BCS and 138 midlife women without cancer was analyzed from a behavioral intervention trial for menopausal symptoms.

Results: BCS were taking significantly more prescription medications and a larger variety of different types of medication classifications (p < 0.05) after controlling for group differences (race, noncancer comorbid conditions, marital status, income, and smoking) in demographics. Twenty-four women were taking at least one medication considered to be a cytochrome P450 isoforms (CYP) inhibitor or inducer capable of clinical drug-drug interactions with no differences in CYP inhibitors or inducers found between groups.

Conclusion: BCS are taking a vast array of medications during survivorship. It is unclear if prescription medications are managed by a single healthcare provider or several providers. Clinical implications are to monitor for possible interactions among the various prescription medications, over-the-counter medications, and supplements. Implications for behavioral and biomedical research are that clinical studies need to carefully assess and account for multiple medication uses. RELEVANCE OF THE STUDY: The findings of this study are relevant to research and practice for both oncology and general practitioners. The importance of assessing medication information provides information about symptom management in individuals surviving cancer. In addition, the potential interaction of drugs impacts efficacy of various treatments and impacts compliance by patients.