Departments: Your Questions Answered
Q Is it true that combining drugs is the best way to treat malignant brain tumors?
DR. LYNNE P. TAYLOR RESPONDS:
A Since combining chemotherapy with other cancer drugs has been around for decades, I suspect your question was raised by the promising results of a recently published study regarding the two-drug regimen of bevacizumab (Avastin) and irinotecan (Camptosar) to treat malignant brain tumors.
In this clinical study that was published in the Journal of Clinical Oncology in 2007, patients with brain tumors were treated with a combination of bevacizumab and irinotecan. The combination was found to be an effective treatment for recurrent brain tumors.
Bevacizumab is an antibody that recognizes and attacks a protein produced by cells that stimulates the growth of blood vessels. By shrinking the vessels, bevacizumab starves the brain tumor of blood and nutrients.
Irinotecan is a chemotherapy drug that inhibits topoisomerase 1, an enzyme that winds and unwinds DNA. By cutting the DNA strand, the drug kills the tumor cells.
The treatment thought to be best for malignant brain tumors has been a combination of oral chemotherapy drugs with radiation and surgery. Unfortunately, malignant brain tumors always recur, and bevacizumab and irinotecan have been used as a final therapy when they do. Now, because of the positive results of the 2007 study, a larger clinical trial is underway to test the effectiveness of the combination chemotherapy drugs as an initial treatment for malignant brain tumors. Once those results are published, we'll know even more about the efficacy of this drug combination.