Cancer Prevention Is Within Your Control
By Dr Wong Chek Hooi
Consultant
Dept of Geriatric Medicine
Singapore General Hospital

Cancer is the leading cause of death in an ageing society like Singapore. Last year it accounted for 26.4 per cent of mortality. Cancer is largely a disease of human behaviour; an estimated 50-70 per cent of cancer mortality is attributable to factors primarily related to human behaviour.

Healthy cells regenerate regularly using genes. Our existence is dependent on the precise genetic regulation of these cells. Ageing and certain environmental factors can cause genes to mutate. In turn, gene mutation may cause healthy cells to turn to bad or malignant cells. Hence, as gene mutations accumulate, the risk of cancer increases.

Studies have shown that about 70 per cent of gene mutations are affected by the environment we live in, which to a large extent is relatively controllable. These include environmental factors such as the food we eat, whether we smoke, or exercise, and our exposure to carcinogens and radiation.

A consistent finding in epidemiological studies is that those who indulge in high intake of food, or who overeat (in terms of calories), have a higher risk of cancer. However, equally important is the manner in which the food is prepared. Food which is cooked in high temperature or is fried food tends to be less healthy as it produces more carcinogens, such as heterocyclic amines. It has been suggested that intake of low-fat, high-fibre, high-fruit and vegetable diets will decrease the risk of cancer.

Other behavioural risk factors include tobacco use and low physical activity, both of which pose the greatest challenge to control. Tobacco use is related to cancer risk and mortality as well as to other diseases such as stroke and cardiovascular diseases. Low physical activity, which is linked to obesity, is also a contributor to cancer risk.

Meanwhile, the search for cancer prevention is continuing. So far findings from some studies on the use of anti-oxidants to prevent cancer have identified some potential preventive agents, including dietary polyphenols, green tea, resveratrol and curcumin. But, these findings are not conclusive. More work is now being done to investigate their use in cancer prevention.

The prospects of finding prevention for cancer are good with so many studies being done to pinpoint the specific agents. In fact, studies on gerontology may well find that many of the disease processes related to ageing, including cancer, do share certain molecular alterations that could be treated by the same preventive approach.