Cancer is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, do not invade or metastasize. Most cancers form a tumor but some, like leukemia, do not. The branch of medicine concerned with the study, diagnosis, treatment, and prevention of cancer is oncology. For cancer treatments, one has to approach specialized health centers dealing with cancer and related diseases.
Certain established carcinogenic factors are–
- Tobacco smoking – associated with cancers of lung, mouth, throat and larynx and also esophagus, stomach kidney & bladder.
- Ultra violet light from strong sunlight is responsible for increased incidence of skin cancers.
- Viruses like Epstein Bar virus is associated with increased incidence of cancer of nasopharynx.
- Betel nut, paan, gutkas chewing is associated with cancer of mouth.
- Chronically irritated & damaged tissues are more likely to develop a malignant change.