The global burden of cancer.

The number of new cancer cases, and the annual incidence rates, of 25 different cancers have been estimated for the year 1990 for every country of the world. The distributions of the most common cancers in men and women are presented for 23 broad 'Areas'. The total number (excluding non-melanoma skin cancer) was 8.1 million, just over half of which occur in the developing countries. The most common cancer is lung cancer, which accounts for 18% of cancers of men worldwide. Stomach cancer is second in frequency (almost 10% of all new cancers) and breast cancer--by far the most important cancer of women (21% of the total) is third. There are very large differences in the relative importance of the different cancers by world area; some of the factors, environmental and genetic, underlying the geographic distributions, are discussed.