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.
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 bodyand cause new cancer growths.
The cancer cells rapidly multiply. Some cancers also produce angiogenic 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.
Management Of Cancer :
The treatment or management of cancer depends on an accurate diagnosis. Diagnosis is made through microscopic observations(tissue biopsy), study of markers on the surface of cells, cytochemical methods, cytogenetics and various scanning and ‘x’ ray diagnostic methods. In order to compare results and for communicating treatment
programme among medical personnel staging systems are essential (Ex: stage1, stage2) staging defines tumours as either confined to the tissue of origin or having spread to local tissues and organs and finally as having metastasized. After diagnosis, treatment of cancer involves surgery, chemotherapy, radiotherapy and hormonal treatments. Till last century, surgery was the only effective method of treatment. Even to-day through surgery biopsy can be effected for diagnosis. If the tumour is restricted to the primary site, through surgery it can be removed. In latest treatment procedures surgery is restricted to affected region, rather than amputation or removal of the entire organ.
Radiotherapy :
Discovery of x-rays by Roentgen(1895) and of radioactivity by Curies in 1899 opened new ways of treating cancer. In Radiotherapy high energy ionising radiations are used. The radiations used are x-rays and gamma rays or subatomic particles such as beta particles, high energy electrons and neutrons or charged particles like helium ions. Ionising radiations can penetrate tissues. They can damage DNA leading to cell death and mutagenesis. The basis of radiation therapy depends on the differential sensitivity of the tumour tissue and the normal tissue. Hence the aim of radiotherapy is to prescribe sufficient radiation dose to the tumour, sparing as much of the normal tissue as possible.
Chemotherapy :
The purpose of chemotherapy is to prevent cancer cells from multiplying, invading and metastasizing. The chemicals used in treatment affect cell multiplication and tumour growth. Several drugs are now available for usage. They can used singly or in combination. Some cancers like breast cancer are hormone dependent. Hence hormones are used in their management. Inspite of all advances in diagnostics and treatment, the death rate due to cancer is greater. Primary prevention of cancer will be a better alternative to diagnosis and treatment. 70% to 80% of cancers result from environmental causes. Hence public awareness towards environmental issues is a need. 33% of cancers in India are tobacco related. Hence smoking cessation and other measures to reduce tobacco usage are to be insisted upon. Consumption of fibrous food and avoidance of fatty food will avoid tumours related to alimentary canal. Thus it is apparent that fight against cancer will be successful with early detection and appropriate education for avoidance.
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