Although the findings are preliminary and must be confirmed by other studies, the investigators found that vitamin C, beta-carotene, and antibacterial drug alone and in combination helped to prevent gastric cancer in people at high risk for the disease. Chemoprevention with retinoids has been the subject of Dr. Hong s work over the past 10 years. He and other investigators now suspect that retinoids may be able to reverse premalignant lesions in the lungs of chronic smokers, or at least former smokers, by correcting abnormalities in the expression of retinoic acid receptors. As with other chemoprevention research, however, much needs to be learned about the specific molecular and genetic changes in bronchial tissue, and when during the carcinogenic process these changes occur. Another chemopreventive agent, oltipraz , has also shown promise for patients at risk for lung cancer.
Prostate cancer is also under study in chemoprevention trials.
One factor highlighted in this study is the demographic make-up of the trial population. These demographic characteristics are consistent with the data from other chemoprevention trials, and they may have implications for the design of these trials. There is also increasing interest in gamma-tocopherol and prostate cancer prevention. Meanwhile, tamoxifen continues to stir debate. They also found that the drug s effects are minimal and expensive from a health-policy perspective for women older than 60 years.