Should Supplemental Antioxidant Administration Be Avoided During Chemotherapy and Radiation Therapy?

Abstract

Despite nearly two decades of research investigating the use of dietary antioxidant supplementation during conventional chemotherapy and radiation therapy, controversy remains about the efficacy and safety of this complementary treatment. Several randomized clinical trials have demonstrated that the concurrent administration of antioxidants with chemotherapy or radiation therapy reduces treatment-related side effects. Some data indicate that antioxidants may protect tumor cells as well as healthy cells from oxidative damage generated by radiation therapy and some chemotherapeutic agents. However, other data suggest that antioxidants can protect normal tissues from chemotherapy- or radiation-induced damage without decreasing tumor control. We review some of the data regarding the putative benefits and potential risks of antioxidant supplementation concurrent with cytotoxic therapy. On the basis of our review of the published randomized clinical trials, we conclude that the use of supplemental antioxidants during chemotherapy and radiation therapy should be discouraged because of the possibility of tumor protection and reduced survival.

The Role of Biomarkers of Oxidative Stress in Breast Cancer Risk and Prognosis: A Systematic Review of the Epidemiologic Literature

“…11 Many cancer treatments, such as radiotherapy and certain chemotherapy agents, act through oxidative stress pathways via the production of ROS to kill tumor cells. [12][13][14] Several biomarkers of oxidative stress have been identified for use in epidemiologic studies and can be measured in various biological samples, including both blood and urine. 7,[15][16][17][18][19][20][21] Commonly used biomarkers include DNA damage biomarkers, such as 8-hydroxy-2¢-deoxyguanosine (8-oxodG), 22 protein carbonyl groups as a marker of protein oxidation, 23 and malondialdehyde (MDA) and F2-isoprostanes as markers of lipid peroxidation.…”

Boosting Cancer Survival in Nigeria: Self-management Strategies

“…Therefore, depending on individual cancer stage and symptoms, one should consume enough nutrients and calories to nourish the body and prevent weight loss or gain. The use of dietary supplements are not advised except in the treatment of a particular deficiency as many supplements contain nutrient levels which exceed that recommended for optimal health and so may be detrimental to survivors since they could prevent the cellular oxidative damage to cancer cells that is required for treatments such as radiation therapy and chemotherapy to be effective (Lawenda et al, 2008;Rock et al, 2012). Diet Recommendations: Cancer survivors are advised to increase fruit and vegetable consumption; reduce saturated fats; use healthy fat sources like olive oil; limit processed eat whole grains rather than processed grains [Davies et al, 2010;American Cancer Society, 2012b].…”

Nutrition in oncology: the case of micronutrients (Review)

“…Meanwhile a large number of survey studies (60)(61)(62)(63)(64)(65)(66)(153)(154)(155)(156)(157)(158)(159) have been published, some of a systematic nature (56,57), summarizing and evaluating the findings. In this context, two contradictory positions have developed expressed by two different views (147) maintaining that the administration of antioxidant supplements (in higher doses) as an adjuvant to chemo and/or radiation therapy: i) is not associated with any negative effects on the tumordestroying therapy; and ii) is associated with a weakening of the tumor-destroying therapy.…”

“…Against this background it is evident that a supportive nutrition therapy should be an integral part of cancer care (44)(45)(46). In addition to a sufficient supply of energy substrates, vitamins and minerals as well as long-chain ˆ-3 fatty acids are becoming more and more interesting (31, [47][48][49][50][51][52][53][54][55][56], although the therapeutic benefit of such supplements is the subject of a controversial discussion, especially in respect ONCOLOGY REPORTS 24: 815-828, 2010 of supplements with high concentrations of antioxidants like the vitamins C and E and the trace element selenium (57)(58)(59)(60)(61)(62)(63)(64)(65)(66).…”