Cancer and death
A severe onset of cancer ends in the death of a person. It is because of the unique characteristics of the cancer cells. The growth of normal cells is controlled by certain factors. However the cancer cells do not require the growth factors. Hence these cells do not respect usual cellular growth limits.
Normal cells have a nature of remaining together in tissues. But the cancer cells are less adhesive to each other. Hence they wander through the tissues and enter the blood. They can be transported to all parts of the body and cause new cancer growths.
The cancer cells rapidly multiply. Some cancers also produce angio-genic factors that cause many new blood vessels to grow into the cancer. Thus these cells will drain all the nutrients and normal cells get deprived of food. Ultimately the normal cells and tissues suffer nutritive death.
Majority of the cancers are caused by living habits and environmental factors.
1. Tobacco :- Nearly 35% of all cancer deaths are due to usage of tobacco in some form. Atleast 90% of lung cancer deaths are due to smoking. Smoking can also affect gastro-intestinal tract, pancreas, genito-urinary tract and upper respiratory passage. Snuff and chewing tobacco can affect mouth and respiratory tracts. Smoke inhaled by non-smokers (passive smoke) can also cause lung cancer and blood cancer.
2. Exposure to ionising radiations such as x-rays, gamma rays, uv rays can produce cancer. These radiations rupture DNA strands, causing mutations. Solar radiations can cause skin cancers.
3. Physical irritants, such as continued abrasion of the linings of the intestinal tract by some types of food can also lead to cancer. Dietary substances such as fat, high calorie intake of animal proteins, salted or smoked food can cause cancer in Breast, Colon, Stomach and Oesophagus.
4. Certain drugs if taken without medical advice can cause cancer.
5. Viruses and parasitic organisms like schistosoma, liverfluke can also affect.