New ways of treating brain tumors are being investigated, including modifying existing treatments as well as developing new ways to give the treatments.
To get chemotherapy drugs past the blood-brain barrier, for example, researchers are increasing the dosages and injecting the drugs directly into the blood vessels of the brain. A new method puts the chemotherapy right at the tumor site. After surgery, small biodegradable plastic wafers can be put in where the tumor was. These wafers release chemotherapy drugs right there.
Something similar can be done with radiation therapy. After a tumor is removed, a surgical balloon is put in the cavity left by the tumor. The balloon is filled with liquid radiation, and over the next week, it radiates the tissue around it to kill off any remaining cancer cells.
Antiangiogenesis
Researchers are looking at tumor treatment from many exciting angles. One of these approaches is antiangiogenesis. This means cutting off the blood supply to a tumor so that not only will it not grow, it will shrink and die. One study tried an antioangiogenic drug, Thalidomide, with patients who had very serious gliomas that hadn't responded to radiation and/or chemotherapy. One year after starting the drug, 25% of the patients were still alive, although their tumors were still growing. The researchers suggested that perhaps Thalidomide could be tried in newly-diagnosed patients, and combined with radiation and chemotherapy.
Using the immune system
Another approach to glioma treatment being examined is using the body's own immune system to fight off the tumor. Researchers in a study took 19 patients with gliomas, made a vaccine for each one using his/her own tumor cells, and after the vaccination stimulated each person's production of white blood cells (which fight off infection). Seventeen of the patients showed a response to the vaccine. In eight patients, the researchers could see the response on x-ray, and five of the patients actually improved. Some of the patients lived as long as two years after the treatment.
Poliovirus
A possible treatment that received news coverage is the use of poliovirus to attack gliomas. Researchers discovered that the poliovirus has a natural attraction to a chemical that is found on malignant gliomas. However, since they didn't want to cause polio, they used genetic engineering to take a piece of the virus that causes colds (rhinovirus) and put it in the poliovirus. This "deactivated" the disease-causing part of the poliovirus. The researchers created gliomas in mice, then tested the new virus on the tumors. They were excited to see that the tumors were eliminated. The next step will be designing a research study to test the virus in humans.
Sources:
- American Brain Tumor Association. Facts and Statistics.
- American Society For Microbiology. "Genetically engineered poliovirus fights brain tumors." Press release, May 22, 2001.
- Fine, H. A., Figg, W. D., Jaeckle, K, et al. (2000). Phase II trial of the antiangiogenic agent Thalidomide in patients with recurrent high-grade gliomas. J Clin Oncol, Vol. 18, No 4, pp 708-715.
- Flowers, A. (2000). Brain tumors in the older person. Cancer Control, Vol. 7, No. 6, pp 523-538.
- National Cancer Institute. What You Need to Know About Brain Tumors.
- Sloan, A. E., Dansey, R., Zmorano, L., Barger, G., Hamm, C., Diaz, F., Baynes, R., Wood, G. (2000). Adoptive immunotherapy in patients with recurrent malignant glioma. Neurosurg Focus, Vol. 9, No. 6.
- Wake Forest University Medical Center. "Wake Forest first in world to perform new brain tumor treatment." Press release, May 25, 2001.
