Primary and secondary prevention in the reduction of cancer morbidity and mortality

Overall, cancer is a highly preventable disease. Indeed, modifiable externa l factors. discovered by epidemiological studies during the last 50 years, account for a majority of all cancer deaths. In this review, we discuss bri efly these factors and their contribution to the current burden of cancer w ith an emphasis on the developed countries. Needless to say, tobacco smokin g remains the largest contributor to the cancer landscape, whilst the contr ibution of poor diet and obesity may be equally important, but much more di fficult to quantify. Our main goal was to assess what prevention of cancer has accomplished and might accomplish in the next two decades. Based on (ne cessarily crude) estimates, age-adjusted mortality rates from cancer in yea r 2000 had been reduced by approximately 13% due to primary prevention and an additional 6% due to the combined effect of early diagnosis and screenin g (secondary prevention). According to a realistic goal for the year 2020, a further 29% reduction might be achieved by primary, and 4% by secondary p revention. The main contribution to such accomplishments would be a reducti on in tobacco smoking, improvements in diet-including reduced alcohol intak e-and arrest of the obesity epidemic, in part through increased physical ex ercise. Rather than being granted, these goals require great effort and maj or commitment from all those who share responsibility for public health. (C ) 2001 Elsevier Science Ltd. All rights reserved.