Antioxidants And Toxicity Of Cancer Chemotherapy: A Systematic Review Of The Evidence From Randomized Controlled Trials

9130 Background: Much debate has focused on whether or not antioxidants interfere with the efficacy of cancer chemotherapy. The objective of this study is to systematically review the medical literature to compile results from randomized, controlled clinical trials evaluating the effects of concurrent use of antioxidants with chemotherapy on toxic side effects. Methods: We performed a search of literature from 1966-December 2006 using MEDLINE, Cochrane, CinAhl, AMED, AltHealthWatch and EMBASE databases. Randomized, controlled clinical trials reporting mitigation of chemotherapy toxicity were included in the final tally. The searches were performed in duplicate following a standardized protocol. No meta-analysis was performed due to heterogeneity of cancers and chemotherapy regimens. Results: Of 848 articles considered, 32 trials met the inclusion criteria. Antioxidants evaluated were: glutathione (9), melatonin (6), vitamin A (1), an antioxidant mixture (3), N-acetylcysteine (3), vitamin E (5), selenium (1), L-carnitine (1), Co-Q10 (2) and ellagic acid (1). Subjects of most studies had advanced or relapsed disease. Conclusions: One of the 32 studies included reported evidence of significant increase in toxicity from the concurrent use of antioxidants with chemotherapy. In 18 studies, antioxidant groups experienced significantly lower toxicity than control groups. Statistical power and poor study quality were concerns with some of the studies. We have reported elsewhere that randomized trials of various antioxidants given with chemotherapy did not demonstrate an adverse effect on treatment response or survival. Well-designed studies evaluating larger populations of patients given antioxidants concurrently with chemotherapy are thus warranted. No significant financial relationships to disclose.