Risk evaluation of the use of complementary and alternative medicines in cancer

Introduction. - Cancer patients use complementary and alternative medicines (CAM) to improve their well-being. Little is known about real risks. Objective. - To highlight 3 different types of axes: 1/cancer patients' perceptions concerning CAM; 2/misinformation/miscommunication about CAM; 3/CAM toxicity (direct toxicity, CAM anticancer drugs, CAM-cancer interactions). Method. - A questionnaire was proposed to cancer patients for 2 months. The CAM toxicity was analyzed if patients documented their drugs and CAM. Results. - Eighty-five patients responded: 72/85 were taking >= 1 CAM. In total, 95% patients were satisfied. There was an increasing CAM intake after cancer diagnosis. One hundred and seventeen different CAM were identified (63 herbs, 24 essential oils, 28 food supplements, 2 homeopathic specialities). Only 30/85 were aware CAM could interact with anticancer drugs. No other type of risk was perceived. Information sources: 43/85 Internet, 38/85 general practitioner, 38/85 community pharmacist, 32/85 entourage, 25/85 other patients, 22/85 oncologist. In total, 81.3% questioned healthcare professionals (HCP) about CAM. Twelve patients noticed HCP lacked knowledge regarding CAM. The toxicity analysis was carried out for 24 patients who consumed 1 to 24 CAM. In total, 133 CAM were reported, including 87 different CAM. For only 43 CAM/87, studies were found. All patients presented >= 1 risk: 14 at risk of CAM-cancer interactions, 15 of CAM-anticancer drug interactions, 21 of CAM direct toxicities. Conclusion. - Many CAM are used by patients. The diagnosis of cancer favors their use. The risks are manifold: low perception of risk that can be induced by CAM, diverse and insecure sources of information and many potential toxicities that are not scientifically documented. (C) 2020 Academie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.