Estimating the Preventability of Cancer

Nearly 30 years ago Doll and Peto, examining the geographic distributions of cancer around the world, estimated that as much as a third of all cancer might be due to the combined effects of various nutritional factors. The American Institute for Cancer Research and theWorld Cancer Research Fund has conducted a systematic review of all the scientific evidence accumulated since that time, and based on findings of many hundreds of epidemiologic studies and trials conducted around the world, has produced new estimates of the proportions of various cancers that are caused by nutritional factors, including poor diet quality, body fatness, and physical inactivity. Those estimates, published in the 2009 AICR/WCRF report “Policy and Action for Cancer Prevention”, will be summarized and discussed in this presentation. Overall, AICR/WCRF estimates that about a quarter of all cancer can be attributable to nutritional factors in the USA, where nutritional factors account for about 70% of endometrial cancers, 65% of all upper GI cancers, 45% of colorectal cancers, 39% of pancreatic cancers, 38% of breast cancers, 24% of kidney cancers, and 11% of prostate cancers. Although estimates of preventability vary across regions of the world, due to differing mixes of types of cancer, and to differing prevalences of risk factors, it is clear that nutritional factors are a very substantial preventable cause of cancer everywhere. Especially important are the combined effects of excess body fatness and physical inactivity, which are growing global problems, and which increasingly adversely affect populations that experience social inequalities in cancer prevention, detection, and treatment.