The News Line Thursday April 5 2012 PAGE 9 Science Half of all cancer is preventable! BY A SCIENCE CORRESPONDENT MORE than half of all cancer is preventable, and society has the knowledge to act on this information today, according to Washington University public health researchers at the Siteman Cancer Center in St Louis. 'We actually have an enormous amount of data about the causes and preventability of cancer,' says epidemiologist Graham A. Colditz at the Siteman Cancer Center. 'It's time we made an investment in implementing what we know.' Specifically, the researchers cite data demonstrating that smoking alone is responsible for a third of all cancer cases in the United States. Excess body weight and obesity account for another 20 per cent. But beyond individual habits, they argue that the structure of society itself - from medical research funding to building design and food subsidies - influences the extent of the cancer burden and can be changed to reduce it. The obstacles they see to implementing broad cancer prevention strategies are: • Scepticism that cancer can be prevented. Smoking rates in different states demonstrate that 75 per cent of lung cancer in the United States could be prevented with elimination of cigarette smoking. • The short-term focus of cancer research. Benefits of prevention may be underestimated because they take decades to show up, and research funding often spans five years or less. • Intervening too late in life to prevent cancer. Strategies like vaccination against cancer causing viruses, such as the human papilloma virus that causes cervical cancer, work best when begun early, in this case before young people begin sexual activity. • Research focuses on treatment, not prevention. Treatments focus only on a single organ after diagnosis but behavioural changes reduce cancer and death rates from many chronic diseases. . • Debate among scientists. They say health experts have a moral responsibility to highlight cancer risk factors even without knowing the biological mechanism by which they cause cancer. • Societal factors that affect health. Tobacco policy and government subsidies don't do enough to discourage unhealthy behaviour, and in some cases they make the unhealthy options more accessible, especially in low-income communities. • Lack of collaboration across disciplines. Scientists and health experts must work together to learn what causes cancer, communicate that to the public and work with community leaders to implement policies that help people lead healthier lives, they say. • The complexity of implementing broad changes. With so many players involved, from health-care providers to government regulators to individuals, it will be difficult to implement broad change over the long term. Co-author Sarah J. Gehlert, the E Desmond Lee Professor of Racial and Ethnic Diversity at the Brown School of Social Work and the School of Medicine, said: 'Stricter tobacco policy is a good example. But we can't make policy change on our own. We can tell the story, but it requires a critical mass of people to talk more forcefully about the need for change.' http://www.wrp.org.uk