Cancer is caused by various factors. Tobacco, viral infections, chemical and radiation exposure, occupational exposures like asbestos and dyeing industries and genetic inheritance are some of the known risk factors leading to cancer.

Some of these risk factors are modifiable like stopping tobacco use, protection against viral infections, healthy lifestyle behavior, and safe occupational health practices etc. Certain other factors like hereditary factors, natural exposure to radiation etc can not be modified but can be controlled with appropriate health care.