Cancer risk factors
There is no one cause of cancer, but scientists have identified a number of factors that can increase (risk factors) or decrease (protective factors) the chances of getting cancer.
Radiation
Ionising radiation such as X-rays and radiation given off by radioactive materials can cause chemical changes that can damage the DNA in cells. In cancerous cells, this damage can lead to the death of the cell, but healthy cells have mechanisms to repair DNA damage from radiation. Sometimes, the repair is not perfect and the cell can end up with a mutation that can lead to cancer.
Sunlight
Ultraviolet light, even though it is not ionising radiation, can be pretty nasty to DNA as well, and this damage can lead to skin cancer. Melanin, the pigment in skin, stops UV from penetrating the skin, so people with darker skins have a lower chance of developing skin cancer. Ultraviolet light can also have beneficial effects – it is needed for the production of Vitamin D in the skin, which can protect against cancer. Many of our ancestors came from Europe, where there were low levels of ultraviolet light, and evolved lighter coloured skin as a result. In New Zealand, the UV levels are much higher and, as a result, we have the highest level of skin cancer in the world.
Sunbathers
UV radiation absorbed from the sun can cause cancer. UV radiation has been shown to cause cancers such as melanoma, an aggressive skin cancer.
Chemicals
Cigarettes
Exposure to different chemicals can increase your risk of cancer. For example, exposure to the chemicals in tobacco smoke is a major risk factor for the development of lung cancer.
Exposure to different chemicals can increase your risk of cancer. For example, exposure to the chemicals in tobacco smoke is a major risk factor for the development of lung cancer. Alcohol consumption can also increase the risk of some cancers – heavy drinking will increase your risk of getting cancer of the mouth, throat, oesophagus, larynx or liver, and even moderate drinking will increase your risk of getting breast cancer. Exposure to asbestos fibres – a material that was used in buildings to protect them against fire – can lead to a serious lung cancer called mesothelioma.
Asbestos warning
Asbestos is a carginogenic material. Inhalation of asbestos has been proven to cause serious illness. In the 1980s many countries banned the use of asbestos and implemented safety programmes for the removal of asbestos. Here a man in full safety gear is preparing a site for the removal of asbestos.
Genetics
Some people carry genes that make cancer a lot more likely. Recently, scientists have identified specific genes responsible for certain types of cancer, such as the BRCA genes for breast cancer. If you have had a close relative develop cancer, statistically, you are at a higher risk of developing cancer in the future.
Viruses
Certain viruses can increase your risk of getting cancer. One of these is the human papilloma virus, which can lead to cervical cancer. Cervical cancer is linked to sexual activity, which can lead to the spread of the papilloma virus. Safe sex precautions such as the use of condoms can reduce the spread of this virus.
Food
Food can both protect you from cancer and increase your risk; it all depends on what you eat. There are naturally occurring chemicals in fruit and vegetables that protect you from cancer, which is one of the reasons why scientists recommend that you have a least five servings of fruit and vegetables per day. Food can protect in other ways, for example, having a diet high in fibre makes it easier for food to move through your digestive system, decreasing the risk of colon cancer. On the other hand, having a diet high in fat increases your risk of getting cancer because some chemicals attach to fat molecules, and they tend to stay in your body longer or remain in cells with the fat as deposits.
Fatty foods
A fat saturated meal of steak and chips. Having a diet high in fat increases your risk of getting cancer. This is because some chemicals attach to fat molecules, and they tend to stay in your body longer or remain in cells with the fat as deposits.
Related content
Read more about what is cancer, how people find out they have cancer and the various imaging methods used to help with cancer treatment.
Activity ideas
In these activities students can explore cancer screening and diagnosis, the characteristics of normal and cancerous cells and cancer definitions.
Useful links
Te Aho o Te Kahu Cancer Control Agency is a government agency created in recognition of the impact cancer has on the lives of New Zealanders.
Find out more about cancer with the New Zealand Cancer Society.
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