The most common tumors in the brain, glioblastomas, affect the brain's support cells. Recurrent glioblastoma results from tumors developing after treatment, sometimes in areas remote from the original tumor site. Most treatments for this form of cancer attempt to control the resurgence of tumors, which may be in multiple locations.
The initial treatment for recurrent glioblastoma typically involves surgery. Whenever possible, doctors usually attempt to excise as much of the tumor as possible in order to keep the tumor from reappearing later. Sometimes, instead of invasive surgery, doctors will opt for radiosurgery, where focused beams of radiation are directed at tumor sites. If there are multiple tumors in different locations, radiosurgery is often a less harmful option with much less healing time required.
Radiation therapy is usually the next adjunct therapy for this form of glioblastoma. Targeted radiation is typically used, although this is not as focused as radiosurgery. Studies have not shown that exposing the entire brain to radiation significantly improves survival rates. When radiation was used to attack the areas where surgery was performed, however, survival rates more than doubled. This may be the result of the radiation's ability to kill any tumor cells that were not removed via surgery.
Chemotherapy uses powerful drugs to attack cancer cells. Many types of chemotherapy are more global in nature than surgery, making it a useful tool for treating recurrent glioblastoma. Drugs like temozolomide are often used, as they interfere with the tumor cells' ability to replicate.
There are also some targeted types of chemotherapy. The drug bevacizumab may be injected near tumor sites, and it works to prevent tumor cells from generating blood vessels to provide them with nourishment. When combined with more traditional chemotherapies, bevacizumab was found to greatly improve survival rates. This combination of therapies also reduced swelling of the brain, which mitigated the need to take other drugs to control this symptom.
Recurrent glioblastoma can cause a variety of harmful effects to nearby tissue, including seizure activity and headaches from swelling. Patients with this cancer generally have to take other drug therapies to avoid these effects. These drugs can include anticonvulsants as well as steroids, which can reduce swelling and relieve pressure.
As with most cancer treatments, a combination of these therapies usually results in the best chance for survival. Some doctors have focused on using radiosurgery and chemotherapy to control recurrent glioblastoma. Both of these therapies can treat several tumor sites quickly, and they work together to prevent tumors from reappearing. One study found that combining therapies in this way can improve survival rates by several months.