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.
Chemotherapy for breast cancer. Chemotherapy (chemo) is treatment with cancer-killing drugs that may be given intravenously (injected into a vein) or by mouth. The drugs travel through the bloodstream to reach cancer cells in most parts of the body.Chemo is given in cycles, with each period of treatment followed by a recovery period.ome drugs are given more often. Adjuvant and neoadjuvant chemo is often given for a total of 3 to 6 months, depending on the drugs that are used. Treatment may be longer for advanced breast cancer and is based on how well it is working and what side effects you have.