Treatment with a derivative of vitamin A called retinoic acid was associated with reduced lung cell growth in a group of former heavy smokers, according to a study published online October 30 in the Journal of the National Cancer Institute. Former smokers remain at elevated risk for lung cancer. According to one hypothesis, lung cells that were damaged during years of smoking may continue to grow and evolve into cancer even after that person has quit smoking. Previous studies have suggested that retinoids, a class of drugs related to vitamin A, may be effective for preventing lung cancer in former smokers. Retinoids have also been shown to slow the growth of cancer cells in laboratory experiments.
