Oxidative stress and antioxidant status in cancer patients and healthy subjects, a case-control study.

Since raised oxidative stress (OS) or weak antioxidant defence or both are considered to be important players in multimechanistic pathogenesis of cancer, the present study was undertaken to evaluate their possible involvement in the pathogenesis of this disease in the local population. Levels of plasma vitamin C, vitamin E, total antioxidant activity (TAA) and thiobarbituric acid reacting substances (TBARS) as a marker of OS were measured in 20 cancer patients (Mean age 63.1 + 9.3 yr.) and 20 age, sex and socioeconomically matched healthy subjects (Mean age 63.7+7.8 yr.). Significantly low level of vitamin C (p <0.001), vitamin E (p <0.001) and TAA (p <0.003) were observed in cancer patients, whereas OS was significantly increased in patients as compared to control (p <0.003). Smokers had significantly lowered TAA and significantly raised OS than non-smokers, in both case and control groups. Tobacco chewer patients had raised OS as compared to control. This study supports the thesis that OS is a risk factor in carcinogenesis and that smoking, an established risk factor in cancer, at least partly appears through it.