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 is treatment with high-energy rays or particles that destroy cancer cells. Radiation to the breast is often given after breast-conserving surgery to help lower the chance that the cancer will come back in the breast or nearby lymph nodes.Radiation may also be recommended after mastectomy in patients either with a cancer larger than 5 cm, or when cancer is found in the lymph nodes.f BCS was done, most often the entire breast gets radiation, and an extra boost of radiation is given to the area in the breast where the cancer was removed to prevent it from coming back in that area. The boost is often given after the treatments to the whole breast have ended.