Breast cancer, placing drug interactions in the spotlight: Is polypharmacy the cause of everything?

Abstract

e24027 Background: Breast cancer is the most prevalent and lethal cancer among women. Forty one percent of cases occur in people ≥ 65 years. Decision on cancer treatment is particularly challenging among this group of age given its comorbidities and polypharmacy (PP). The main objectives are the analysis of potential drug-drug interactions (PDDI) in elderly breast cancer patients between daily medications and oncospecific therapy and their probable associations with age, BMI, Mini Nutritional Assessment (MNA), frailty and PP and the adverse effects during oncospecific treatment. Methods: A cohort of 77 patients ≥ 70 years with breast cancer underwent a Comprehensive Geriatric Assessment (CGA) by a Geriatrist at a university hospital. Baseline characteristics of the patients, demographical data, cancer stage, and oncospecific and daily treatments, as well as the complications and derived adverse effects were retrospectively collected using electronic medical records. Moreover, frailty categorization, daily medication number, comorbidities, Lawton and Barthel Index, malnutrition, MNA, BMI were prospectively collected using CGA report. PDDI between daily and oncospecific treatments were analyzed. Results: The median age of patients was 85 years (range 72-95). The median number of daily medications at CGA was 6 drugs (range 0-22) and most of the patients had PP at CGA and during oncospecific treatment (73% and 91%, respectively). Out of 719 PDDI, 530 (74%) were moderate ( r2= 0.72) and the median number of drugs during oncospecific treatment ( r2= 0.73) was 9 (range 3-26). Overall, by using Kruskal Wallis, 59 patients (77%) had any adverse effects statistically associated with frailty categorization and MNA ( p < 0.05). Furthermore, there was a tendency with oncospecific treatment, BMI and age ( p = 0.098, 0.089 and 0.062, respectively). The distribution of major, moderate and minor as well as total PDDI was statistically associated with PP at CGA and during oncospecific treatment ( p < 0.05). Conclusions: CGA should be applied in oncology elderly patients not only to assess clinical outcomes and categorize them in each frailty group but also to analyze PDDI by using specific web databases, thereby improving PP, PDDI and economic costs.