Chemotherapy & Nervous System Tumors
Chemotherapy usually is not used for benign tumors or most malignant brain tumors, which are treated with radiation and/or surgery. The problem with chemotherapy is that it works by interrupting mitosis, the process of cell division. Many brain tumors are already slow-growing, so slowing down the process of their growth and division by chemotherapy often is not effective.
Another problem with using chemotherapy to treat brain tumors is finding or developing drugs that effectively cross through the blood-brain barrier and get to the place in the brain where they need to be in order to do any good.
One drug that has proved to be effective is BCNU. A newer technique enables neurosurgeons to place a wafer soaked with BCNU into the surgical cavity after the tumor has been removed. By applying it directly into the tumorous region of the brain, side effects are limited and the drug has a more beneficial effect. Some tumors are treated by injecting drugs directly into the spinal fluid.
Overall, studies have shown that patients who receive chemotherapy for malignant tumors show improved survival compared to those who do not receive the chemotherapy. The effectiveness of chemotherapy depends on the tumor type (medulloblastomas, anaplastic astrocytomas and glioblastomas respond to varying degrees to certain drugs). Chemotherapy is often used in very young children to delay radiation therapy as long as possible. Some meniongiomas respond to anti-progesterone agents. Most mestastatic brain tumors do not respond to chemotherapy, although there are exceptions. With metastatic brain tumors, the best chemotherapy agent is usually the one that has been the most effective with the primary cancer.
There are many experimental treatments, ranging from novel chemotherapy agents to drug therapy to new ways of applying radiation. As with any serious illness, it is generally a good idea to get a second or third opinion and gather as much information as possible about treatment.