Cancers are non-communicable diseases, which means they cannot be caught from another source. Instead they naturally develop in the body. Cancers occur when cell division goes wrong. This causes cells to grow out of control, which form a tumour. There are two types of tumour:
Cancers are looked for by doctors in a process called screening. This can be in an x-ray, in blood or urine tests, or by using monoclonal antibodies.
Many cancers are caused by smoking or drinking excessive quantities of alcohol. Others are caused by infections such as the HPV virus. Other reasons include the Sun's UV rays and some environmental pollutants. The risk of cancer also increases as we get older.
The most frequent cancers in the UK are breast, lung and bowel cancers, and prostate cancer in men. A quick diagnosis is essential for treating all cancers. Treatment can be:
Many cancers are less likely to develop if people lead healthy lifestyles, such as not smoking, exercising regularly and eating a healthy diet.
Anything that increases a chance of developing a disease is called a risk factor. Risk factors can be part of a person's lifestyle, or substances that a person consumes or their environment. Some diseases are caused by an interaction between risk factors.
Some risk factors have been proved to cause a disease. We know that smoking causes lung cancer. Other risk factors are linked but not proved. The risk factor physical inactivity is linked to increased levels of breast cancer but this has not been proved.
Some diseases, their effects and their risk factors are shown in the table below.
|Obesity||Blood sugar levels cannot be regulated properly||Type 2 diabetes|
|Alcohol||Scar tissue is formed in the liver which stops it removing toxins||Liver cirrhosis|
|Smoking||Smoking causes lung cancer and also the underdevelopment of unborn babies||Lung cancer|