Cancer epidemiology: implications for prevention and treatment

Due to the results achieved in epidemiological research for the last 30 years, we are able to reduce considerably mortality from cancer through prevention and early diagnosis. The data required to accomplish these actions have been provided by epidemiology: (a) Descriptive epidemiology is the study of the frequency and the distribution of cancers, based on data concerning mortality and morbidity. These frequencies vary according to different parameters (i.e., sex, age, geographical situation). (b) Analytical epidemiology is able to pinpoint different risk factors (i.e., alcohol, tobacco, iatrogenic factors) through adequately conducted surveys. Primary prevention can attenuate the incidence of cancers by the suppression or reduction of certain risk factors. Secondary prevention permits the screening and treatment of precancerous lesions and avoids the secondary emergence of cancer (cervix uteri, colon). Early diagnosis is able to detect lesions at an early stage in their evolution where treatment is facilitated and where there are optimal chances of survival (breast). All of these measures for prevention and early diagnosis are being organized as large-scale strategic campaigns (e.g., National Cancer Institute, European Communities).