1 There are over 200 types of cancer.  Anything that may cause a normal body cell to develop abnormally potentially can cause cancer; general categories of cancer-related or causative agents are as follows: chemical or toxic compound exposures, ionizing radiation, some pathogens, and human genetics.
Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. For some types of brain tumour you may have chemotherapy after surgery, to try to prevent the tumour from coming back. Chemotherapy is sometimes given with radiotherapy and for some months afterwards to help people to live longer.hemotherapy works very well for some types of brain tumour but it does not work for all of them. You may have some types of chemotherapy in cycles. You have the drugs for a few days every few weeks.
Radiation therapy can be directed at your lung cancer from outside your body (external beam radiation) or it can be put inside needles, seeds or catheters and placed inside your body near the cancer (brachytherapy). Radiation therapy can be used after surgery to kill any cancer cells that may remain. It may also be used as the first treatment for lung cancers that can't be removed during surgery. For people with advanced lung cancer, radiation therapy may be used to relieve pain and other symptoms. For people with lung cancers that are very small, one option may be stereotactic body radiotherapy. This form of radiation aims many beams of radiation from different angles at the lung cancer.