Cancer is basically a disease of the genes; a disease which may be caused by internal or external factors such as heredity as an example of the former and environmental factors as an example of the latter. Damage to the genes results in cells dividing uncontrollably and one maladjusted cell affecting another and so on until enough damage has been caused to result in cancer.
Although cancer is one of the leading causes of death in the developed world, most cancers can be treated successfully if diagnosed at an early stage.
Cancer and Adults
In developed countries, a quarter of all deaths are caused by cancer. The most common cancer affecting American males are prostrate, lung and colorectal cancer with cancer of the lung the most common cause of death by cancer. American women are affected more frequently by breast cancer followed by cancer of the lung and then endometrial cancer. Again, lung cancer is the most deadly.
Cancer and Children
In children, the majority of cancers make their appearance in the first year of the child’s life, with leukaemia accounting for about 30% of childhood cancer. Boys and girls are affected by basically the same cancers but there is a difference between white infants who are affected by most cancers at a higher rate than black infants.
Causes of Cancer
To understand the causes of cancer, one must understand the process of ‘aptosis’; which is one of the main types of programmed cell deaths, a natural process in the body. Too much aptosis causes cell-loss disorders while too little results in the growth of cancerous tumours. Substances that influence this process by causing gene mutation are called mutagens and mutagens that cause cancer are carcinogens.
Some examples of carcinogens are the smoking of tobacco which can lead specifically to lung cancer and too much sun exposure which can cause skin cancer.
There are some carcinogens which are not mutagens, however, such as alcohol and estrogen. Though they don’t actually damage the genes, it is supposed that they encourage cancer development by stimulating the rate of cell mitosis.
Viruses can also initiate cancer development and are responsible for 15% of human cancers.
A large number of cancers can be prevented by avoiding the carcinogens that cause them. Modifiable lifestyle factors include monitoring alcohol consumption, physical exercise and being overweight.