Objective: The aim of this study was to assess the potential risks of interactions between biologically based complementary and alternative medication (BB-CAM) and conventional drugs during systemic therapy in breast and gynecological cancer patients by analyzing the actual CAM-drug combinations from individual patients' records.
Methods: From September 2014 to December 2014 and from February 2017 to May 2017, all patients (n = 717) undergoing systemic therapy at the Gynecologic Oncology Day Care Unit in the Gynecology and Obstetrics Department of the Technical University of Munich, Germany, were asked to participate in a questionnaire about all their medications. To assess the potential risk of CAM-drug interactions (CDIs), we initially utilized the Lexicomp drug interaction database. This assessment was then expanded with a systematic search of other digital databases, such as the National Center for Complementary and Integrative Health, Memorial Sloan Kettering Cancer Center, PubMed, and MEDLINE as well as the Cochrane Library.
Results: Among 448 respondents, 74.1% reported using BB-CAM simultaneously with their systemic therapy. The assessment showed 1 patient with a potentially clinically relevant CDI, where the interaction was based on a self-medicated combination of Echinacea and cyclophosphamide. Furthermore, 81 patients (18.1%) were thought to have interactions because of a combination of BB-CAMs and cytochrome P450 3A4-metabolized anticancer drugs.
Conclusions: Our data demonstrated high overall use of BB-CAMs by cancer patients undergoing systemic therapy. The analyses showed only 1 clinically relevant CDI.
Keywords: CAM; cancer; chemotherapy; complementary and alternative medicine; herb-drug interaction; oncology; supplement-drug interaction.