Abstract

ROLE OF ANTIOXIDANTS IN CANCER PATIENTS TREATED WITH EITHER CHEMOTHERAPY OR RADIOTHERAPY OR BOTH: PAST, PRESENT, AND FUTURE

Dr. Virendra Kushwaha, Dr. Pooja Agrawal* and Dr. Nasreen Fatma Khan

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Abstract

Oxidative stress is a key component in the carcinogenesis process stimulated by endogenous and exogenous factors, reactive oxygen species (ROS), etc. inducing cellular damage. Because complete recovery of cancer patients following a single treatment is quite difficult, therefore many integrative practitioners converse use of antioxidant supplements, allowing cancer patients to tolerate possibly higher effective doses of chemotherapy, thereby increasing the chance of better anti-tumor response and improving survival rate. As chemotherapy reduces serum levels of antioxidant vitamins and minerals due to lipid peroxidation and thus produces a higher level of oxidative stress. This may reflect a failure of the antioxidant defense mechanism against oxidative damage induced by commonly used anticancer drugs as well as by radiotherapy. Therefore, supplementation of certain antioxidants and nutrients can help to enhance the health status of patients undergoing a continuous regime of chemotherapy and thus can decrease the duration of chemotherapy regimens. Although there are many opinions about the risks or benefits of antioxidant supplementation, the only supportable conclusions based on the present research are that it is difficult to demonstrate definitively that antioxidants ameliorate therapeutic toxicities and that there is no evidence of antioxidant supplementation causing harm to cancer therapy, except for smokers undergoing radiotherapy. In the future, we are focusing on more disease-specific, target-directed, and highly bioavailable antioxidants along with nanotechnology delivery of antioxidants leading to increased therapeutic index and higher drug concentration in tumor tissues.

Keywords: Oxidative stress, cancer, chemotherapy, antioxidant.