CANCER IN DEVELOPING-COUNTRIES - OPPORTUNITY AND CHALLENGE

Epidemiologic observations indicate that environment and lifestyle are the major determinants of the geographical patterns of cancer. The de veloping countries, which account for 75% of the world's population, h ave lower incidence rates of cancer compared with the industrialized n ations but bear more than half the global cancer burden. Demographic t rends resulting from economic progress (decreasing incidence of infect ious diseases, population growth, aging, and urbanization), coupled wi th increased tobacco consumption and dietary changes, indicate that de veloping countries will bear a continually increasing proportion of th e world's cancer burden and its accompanying demand for the provision of costly treatment programs. Yet the developing countries command onl y 5% of the world's economic resources, and health care programs are a lready fully extended and frequently inadequate. Thus, cancer control in the developing countries, including preemptive prevention of the an ticipated increases in cancers presently more common in the industrial ized nations (e.g., lung, breast, and colon), should include much grea ter emphasis on cancer prevention than is presently the case. But ther e is another perspective. The developing countries, with their dramati c contrasts in lifestyles and environments and equally diverse pattern s of cancer, provide an unparalleled, and often neglected, opportunity for studies directed toward understanding the mechanisms of environme ntal carcinogenesis. Such an understanding should eventually lead to t he development of novel intervention approaches. Unfortunately, cancer research is much more difficult to conduct in the developing countrie s because of the lack of population-based registries, poor communicati on and transportation systems, and deficiencies in infrastructure, fin ancial support, and the training of health professionals. These diffic ulties could be overcome, to the benefit of all, if the extent of coll aboration in cancer research between the developing and industrialized nations were to be greatly expanded.