Servicio de Oncología, Hospital General de México, Dr. Balmis #148 Col. Doctores, México DF, 06750, México.
Nutrition. 2013 Jan;29(1):15-21. doi: 10.1016/j.nut.2012.02.014. Epub 2012 Jul 10.
Oxidative stress is a key component in linking environmental toxicity to the multistage carcinogenic process. Reactive oxygen species (ROS) are generated in response to both endogenous and exogenous stimuli. To counterbalance ROS-mediated injury, an endogenous antioxidants defense system exists; however, when oxidation exceeds the control mechanisms, oxidative stress arises. Chronic and cumulative oxidative stress induces deleterious modifications to a variety of macromolecular components, such as DNA, lipids, and proteins. A primary mechanism of many chemotherapy drugs against cancer cells is the formation of ROS, or free radicals. Radiotherapy is based on the fact that ionizing radiation destroys tumor cells. Radiotherapy induces direct lesions in the DNA or biological molecules, which eventually affect DNA. Free radicals produced by oncology therapy are often a source of serious side effects as well. The objective of this review is to provide information about the effects of antioxidants during oncology treatments and to discuss the possible events and efficacy. Much debate has arisen about whether antioxidant supplementation alters the efficacy of cancer chemotherapy. There is still limited evidence in both quality and sample size, suggesting that certain antioxidant supplements may reduce adverse reactions and toxicities. Significant reductions in toxicity may alleviate dose-limiting toxicities so that more patients are able to complete prescribed chemotherapy regimens and thus, in turn, improve the potential for success in terms of tumor response and survival.
氧化应激是将环境毒性与多阶段致癌过程联系起来的关键因素。活性氧 (ROS) 是对内源性和外源性刺激的反应而产生的。为了平衡 ROS 介导的损伤，存在内源性抗氧化防御系统；但是，当氧化超过控制机制时，就会出现氧化应激。慢性和累积性氧化应激会导致多种大分子成分（如 DNA、脂质和蛋白质）发生有害变化。许多抗癌药物针对癌细胞的主要机制是 ROS 或自由基的形成。放射疗法基于电离辐射破坏肿瘤细胞的事实。放射疗法会直接损伤 DNA 或生物分子，最终影响 DNA。肿瘤治疗产生的自由基往往也是严重副作用的来源。本综述的目的是提供有关抗氧化剂在肿瘤治疗过程中的作用的信息，并讨论可能的事件和疗效。关于抗氧化剂补充是否会改变癌症化疗的疗效，存在很多争议。在质量和样本量方面，证据仍然有限，这表明某些抗氧化补充剂可能会减少不良反应和毒性。毒性的显著降低可能会减轻剂量限制毒性，从而使更多的患者能够完成规定的化疗方案，从而提高肿瘤反应和生存的成功潜力。
