3.4 Risk factors for cancers
This section will introduce you to the idea of cancer risk factors that can increase our chance of developing a cancer. Knowing what they are is helpful in educating the members of your community in how they can decrease their cancer risks by changing their behaviour. The factors that are linked with increases in cancer risk are listed in Box 3.1.
Box 3.1 Risk factors for cancer
- Age
- Cigarette smoking and chewing tobacco or khat
- Genetic factors
- Environmental risk factors, such as radiation and certain viruses
- Exposure to some industrial chemicals (e.g. insecticides)
- Lack of exercise
- Fatty diet leading to obesity
- Excessive alcohol consumption.
Which of the cancer risk factors in the above list are capable of being reduced by actions that an individual can take for themselves?
Individuals can reduce their cancer risks from all the potential causes in the above list except age, genetic factors and some environmental risk factors.
Old age is a cancer risk because as we get older our cells accumulate more damage from avoidable risks (e.g. smoking, alcohol) and unavoidable exposures in the environment, e.g. radiation from rocks, viruses that cause cancers, etc. Older cells have less ability to control their own growth, so they are more likely to become malignant and start to form a cancer. Genetic factors can also increase a person’s cancer risk; some families seem to have more than the average number of cancers arising in family members, and this is thought to be due to the existence of certain cancer-promoting genes in their cells.
The good news is that the WHO estimates that over 30% of all cancers can be prevented, and in the next section we will explain how.
3.3.1 Problems in diagnosing cancers from their symptoms