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.
The main treatment for primitive neuroectodermal tumours (PNETs) is surgery to remove the whole tumour or as much of it as possible. If the tumour has made fluid build up in the brain (hydrocephalus) you may need to take steroid tablets until you have an operation.hemotherapy for PNETs. Chemotherapy may be used alongside radiotherapy for older children with medulloblastoma and for adults where there is a high risk of the tumour spreading. Otherwise PNET specialists tend to keep chemotherapy to treat the tumour if it comes back after surgery and radiotherapy.