Physical exercise: a pillar for cancer prevention?

Both epidemiological and experimental studies have shown that physical exercise deserves particular attention in any consideration of approaches to the prevention of neoplasia, especially since it also exerts consistent beneficial effects on the other major chronic diseases prevalent in the Western world, atherosclerosis and non-insulin dependent diabetes mellitus (NIDDM). The organ sites for which strong evidence has been gained for a protective influence of exercise or an elevated risk with a sedentary existence include the colon, prostate, breast and endometrium. The underlying mechanisms appear to centre on the hormones insulin and oestrogen, serum elevation of both of these endocrine factors being associated with increased risk of neoplastic development. The immense potential benefit of an increased level of exercise in the general population suggests that commensurate measures should be taken in the field of cancer education.