Chemotherapy for Brain Cancer
Chemotherapy involves the administration of drugs, either orally or intravenously to kill cancer cells. Malignant tumors need chemotherapy. Brain and spinal tumors can benefit. Skull-based tumors are mostly treated with surgery and radiation. Therapy that falls under medical treatment has a wide range of approaches, including timing of treatment.
Neoadjuvant chemotherapy: Sometimes a tumor is too large to allow resection without damaging adjacent structures. In those cases of brain tumor treatment, chemotherapy and/or radiation before surgery may make the brain tumor shrink, to protect those structures. Neoadjuvant, or preliminary, chemotherapy and/or radiation given before surgery can shrink the tumor and make it more removable. Using chemotherapy and radiation before surgery also helps prevent recurrence.
After surgery: Most chemotherapy is given adjuvant (after surgery), sometimes combinations of drugs that have been shown to work well together for your type of cancer. For patients with cancer that has spread (metastatic), chemotherapy can improve survival and quality of life. Chemotherapy and radiation may both be given after surgery.
Novel combinations of standard-of-care chemotherapy and agents being tested in clinical trials are often good options for patients. Clinicians are also looking at the combinations of surgery for inoperable and hard-to-reach brain tumors with laser interstitial therapy that temporarily opens the blood brain barrier and allows combining it with chemotherapy treatments that otherwise would not have an effect on a brain tumor.
Biological therapy, sometimes called immunotherapy, is a treatment that uses materials made by the patient’s own body or in a laboratory to stimulate the immune system to fight disease. Siteman researchers are now participating in clinical trials to test this form of therapy. These trials are especially important for patients with metastatic and recurrent cancers. Every patient potentially has a mutation that could be harnessed for a vaccine approach. The next couple of years should see a huge advance in the combination of cancer gene sequencing and vaccine development.
Creating a personalized vaccine begins with taking samples of DNA from a patient’s tumor and his/her normal tissue. Researchers at The Genome Institute sequence the DNA to identify mutant cancer genes that differ from the patient’s normal tissue and that make versions of proteins found only in the tumor cells. Then they analyze those proteins to determine which ones are most likely to be recognized and attacked by T cells. Portions of these proteins are incorporated into a vaccine to be given to a patient. Scientists at the Siteman Cancer Center at Washington University and Barnes-Jewish Hospital are in the process of using these vaccines against many different types of cancers including breast, brain, lung, melanoma, and head and neck cancers.
Dendrite approach: Another ongoing clinical trial strategy calls for collecting fresh tumor tissue in the operating room and processing it in a lab into a “soup.” Next, researchers collect immune cells called dendritic cells from a patient and activate them using the tumor soup before they are reinfused into the patient in the form of a vaccine.
Glioblastoma vaccine: Another type of vaccine targets a genetic mutation unique to glioblastoma, the most common high-grade brain cancer and the most aggressive. Early data from these vaccine drugs shows that patients who received the vaccine in addition to the current standard therapy lived more than twice as long as patients who received standard therapy alone. The side effects were, in most cases, no worse than those of a flu vaccine.
Checkpoint blockade therapy: Another approach in immunotherapy trials is called a checkpoint blockade. This immune-based cancer treatment, which has been successful against advanced lung and skin cancers in clinical trials, takes advantage of immune T cells that are present in many tumors but have been shut off by cancer cells activating a safety mechanism called the checkpoint system that prevents immune cells from attacking the body’s own tissues.
Checkpoint blockade drugs in testing disable that safety mechanism, allowing our immune T cells to use their destructive capabilities on the tumors. One danger of this approach is that it increases the chances that those same immune cells erroneously will attack healthy tissue, causing serious autoimmune disease. Researchers have found that by identifying mutated tumor proteins that are the specific targets of the reactivated T cells that attack the tumors, they can create vaccines that only unleash the T cells on the tumors, and so far, tests have been very successful.
Genomic sequencing offers another step forward in personalized cancer therapy. By studying a patient’s DNA, researchers are learning which changes, or mutations, affect responses to a particular drug. Such advances will ultimately mean more treatment options and better outcomes.
Novocure is a novel therapy available at Siteman Cancer Center for treatment of glioblastoma multiform, (GBM) in patients whose brain tumors recur or progress after initial treatment. The device is an alternative to standard medical therapy for GBM after surgical and radiation options have been exhausted. It uses Treating Fields (TTFields) technology, a form of low intensity, alternating electric current that can that exert physical forces on electrically charged cellular components within a tumor, preventing cells from dividing and causing cancer cell death. The current is delivered through a helmet aligned with the tumor and attached to a portable battery pack so patients can wear it night and day.