More than half of all cancers are preventable and medicine has the knowledge to prevent such cancers right away, U.S. researchers suggested. Epidemiologist Dr. Graham A. Colditz, an associate director of prevention and control at Washington University\'s Siteman Cancer Center in St. Louis, said researchers reviewed the scientific literature and outlined obstacles in reducing the cancer burden in the United States and around the world. \"We actually have an enormous amount of data about the causes and preventability of cancer,\" Colditz said in a statement. \"It\'s time we made an investment in implementing what we know.\" In a review article published in Science Translational Medicine found barriers to reducing cancer include: Skepticism that cancer can be prevented by such means as quitting smoking. Benefits of prevention might be underestimated because they take decades to become evident, while cancer research funding often spans five years or less. Intervening too late in life to prevent cancer because of fear of treatment or lack of healthcare access. Research focuses on treatment, not prevention. Tobacco policy and government subsidies don\'t do enough to discourage unhealthy behavior, and in some cases they make the unhealthy options more accessible. Lack of collaboration across disciplines. Getting healthcare providers, government regulators and individuals to implement broad change.