Cancer research efforts focus heavily on early detection and treatment, according to a historical review from the University of Minnesota. Only 2 percent of the National Cancer Institute's budget is used for prevention, according to their estimate. This amount is too low because cancer deaths are still on the rise worldwide. The World Health Organization predicts that 14 percent of all deaths will be caused by cancer in 2018, and this number will rise to 18 percent by 2030. Part of this increase comes from aging of the population, as fewer people die from infectious disease. Everyone has to die from something, but cancer is perhaps the worst option in terms of morbidity and expense.
The earliest efforts to prevent cancer include the observation in 168 B.C. that unhealthy diet is associated with cancer. In the 1700's, early medical researchers noted the cancer risks of tobacco use, the occupation-related scrotal cancer increase in chimney sweeps, and the unusual pattern of cancer in nuns, who have a high incidence of breast cancer but an almost complete absence of cervical cancer. We have made significant progress in preventing occupational cancer risks, but tobacco and sexually transmitted viral disease are still major causes of cancer today.
In 1971, President Richard Nixon signed the National Cancer Act, declaring war on cancer. The goal was to eliminate cancer by 1976. Clearly, the goal is much more difficult than researchers of that time expected.
We know that diet is a factor, but dietary intervention clinical trials have had a low success rate so far. Most of these have focused on small changes, such as the addition of one or two nutrients. The authors of Reference 1 recommended more funding for cancer prevention research, including implementation of Phase 0 trials to identify promising anti-cancer agents and strategies before the traditional Phase 1 trials.
The World Health Organization has identified nine key risk factors for cancer that can be modified by lifestyle changes:
1. Tobacco use
2. Weight in the overweight and obese categories
3. Low fruit and vegetable intake
4. Physical inactivity
5. Alcohol consumption