Anticancer agents and phytotherapy: Interactions that are often unrecognized.

Phytotherapy is the main complementary medicine for which patients afflicted with cancer have recourse but the associated consumption of phytotherapy products gives rise to a risk of interaction with anticancer agents. The aim of this prospective study was to measure the prevalence of the consumption of phytotherapy products as well as their interactions with anticancer agents in a cohort of patients from January 2018 to August 2019. Patients hospitalized in the conventional hematology unit and outpatients who had their prescriptions for oral anticancer agents filled at the hospital pharmacy were questioned about consumption of phytotherapy products by pharmacy externs trained in pharmaceutical interviews. Among the 110 hospitalized patients who answered the questionnaire, 40% (n = 44) used phytotherapy and 5 of them continued to consume it during the cycles of injectable chemotherapy. As a result, 10 interactions were found between the plants and the anticancer agents (prevalence of 27%). Among the 59 outpatients, 17% (n = 10) consumed phytotherapy. Eight interactions were identified (prevalence of 80%). The potential consequences were an increase or a decrease in the concentration of the anticancer agents and an increase in the risk of bleeding, hepatoxicity, and hypokalemia. The consumption of phytotherapy was unknown by a health professional for 44% of hospitalized patients and 60% of the outpatients. The risk of interactions between plants and anticancer agents is not negligible and professionals should be cognizant of this in their daily practice. The availability of tools for training and detection of interactions is indispensable for managing patients undergoing onco-hematology treatments.