Cancers are named according to the tissues from which they arise.
1. Sarcoma - Malignancy in structural tissues Ex: Osteosarcoma (bones), liposarcoma (fa).
2. Carcinoma - Epithelial cancers. Ex : Lung carcinoma, breast carcinioma.
3. Lymphoma - Lymphatic tissues
4. Leukemia - White blood cells.
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.