Review on Antioxidants used in Cancer Prevention

Abstract

Chemoprevention is defined as the use of specific agents to suppress or reverse carcinogenesis and prevent the development of cancer. This is a review to ascertain the effectiveness of antioxidants in cancer prevention and treatment. Antioxidants are the substances which can scavenge free radicals and help to decrease the incidence of oxidative stress induced damage. Prevention of cancer is reviewed from the viewpoints of action mechanisms and clinical trials in order to introduce promising agents discovered by in vitro and/or in vivo studies to applications in humans using systematic method. Epidemiological studies of some published and cohort works on clinical trials from 2002 till date was used in evaluation of chemoprevention of cancer. A good number of the studies showed the effectiveness of fruits and vegetables in cancer treatment. Clinical trials of bladder cancer, prostate cancer, gastric cancer, hepatocellular (liver cells) carcinoma, breast cancer, head and neck cancer, colorectal cancer and lung cancer showed positive result on effectiveness of chemoprevention. Studies also revealed the advantages and toxic effects of these agents, example, in a chemoprevention trial of lung cancer, ?-carotene was unexpectedly found to increase the risk of lung cancer among high-risk groups. It is evident that chemoprevention is effective in cancer treatment and prevention.

Keywords: antioxidants, cancer, prevention and treatment