[Evidence on the prevention of cancer]

Cancer is one of the main health problems. It includes a set of diseases with multi-causal origins. The tumours with the greatest impact on the health of men are lung, prostate and colorectal cancers, while for women they are breast and colorectal tumours. The best strategies for preventing cancer are ones based on primary prevention and early diagnosis. It is estimated that about to 80-90% of cancers are preventable. As regards primary prevention, there is considerable evidence to suggest that not smoking, regular physical exercise and a diet rich in fruit and vegetables, along with the control of some environmental and occupational risk factors can reduce the incidence of cancer. The early diagnosis of breast, colorectal and cervical cancer is recommended for some groups of the population in a context of organised programs with adequate quality guarantees.