Strategies for prevention of cancer in humans.

A substantial amount of epidemiologic and laboratory data indicates that the majority of human cancers should be preventable. In this article, the biologic basis of cancer prevention is presented and the major factors contributing to the initiation, promotion, and progression of cancer in humans detailed. These include tobacco, ultraviolet and ionizing (radon) radiation, certain chemicals (asbestos, aniline dyes), and viruses--both sexually transmitted and endemic. Dietary factors both enhance and inhibit carcinogenesis in humans. In this article, the roles of fat, fiber, and beta-carotene are reviewed with respect to the genesis of breast, colon, prostate, lung, and oral cancers. A large number of prevention trials involving most common malignancies are being conducted in the United States and abroad. This article considers the major strategies and methodology of prevention trials and outlines the major trials now in progress.