Depending on the type of tumor and the promptness of diagnosis. The purpose of surgery is to remove as much of the tumor as possible, to establish an exact diagnosis, to determine the extent of the tumor, and sometimes to provide access for other treatments, such as implants or radiation. As mentioned above, some tumors are inaccessible to the neurosurgeon. Chemotherapy drugs act on DNA- the genetic material found within each cell. The drugs alter the ability of tumour cells to copy their DNA and reproduce.
All cells follow a regular pattern of growth called the cell cycle.
The cycle consists of five successive steps, or phases. Each cell that completes the cycle reproduces itself as two new cells. The two cells produce four new cells, four cells produce eight cells , and so on. In order for a cell to produce normal cells, it must complete specific jobs during each phase of the cell cycle. Each cell must make proteins and enzymes needed to fuel its reproductive process, then duplicate and separate its set of chromosomes.