Is it right to look for anti-cancer drugs amongst compounds having antioxidant effect?

In the recent years, there has been a mounting interest on the use of natural products with antioxidant effect in the management of cancer. If one evaluates search engines will find a burden of papers that have tried to test natural products having anti free radical effects in the management of cancer. But the sense does not seem rational because in cancer we need a compound to kill cancer cells. As a matter of fact, free radicals induce oxidative stress in the body and their deleterious effect in many deliberating diseases that have no exact cure such as diabetes [1], colitis [2], osteoporosis [3], environmental toxins [4] or cancer [5] has been well documented. In spite of this fact, many examples can be given that some although produce free radicals but do not induce cancer such as paraquat toxicity [6] and Alzheimer disease [7].