Glioblastoma is an aggressive cancer that develops in the astrocytes, which are small, star-shaped cells in the supportive tissues of the brain. Because the cells that comprise glioblastomas can vary in their genetic makeup, the diversity of these tumors can complicate treatment. Some therapies can effectively target and destroy certain types of glioblastoma cells while having little to no impact on others. Therefore, glioblastoma treatment often involves a combination of therapies.
Neurosurgery (craniotomy) is one of the most important aspects of glioblastoma treatment, although it must be followed by other treatments. Because glioblastomas invade functioning brain tissue, often in the frontal and temporal lobes of the cerebrum, these fast-growing tumors often cannot be removed in their entirety. Instead, only the mass-forming part of the tumor can be safely removed. Therefore, a craniotomy is performed with the goal of achieving a “maximal safe resection”—removing as much of the tumor as possible while preserving the patient’s brain function and sparing healthy tissues.
After craniotomy, residual cancer cells are usually targeted with additional treatments, such as chemotherapy and radiation therapy. In some cases, investigational treatments may be available through clinical trials.
Moffitt’s individualized approach
At Moffitt Cancer Center, each glioblastoma patient receives a comprehensive treatment plan developed by the multispecialty team in our Neuro-Oncology Program, which includes neurosurgeons, medical neuro-oncologists, radiation oncologists and supportive care providers. After collaboratively determining the optimal combination of therapies for the patient, our team closely monitors the patient’s progress and adjusts the treatment plan as necessary. Our neuro-oncology specialty tumor board meets regularly to review complex glioblastoma cases and determine whether other treatment options should be considered, including groundbreaking treatments that are available only through our robust clinical trials program. “For patients who want the most comprehensive treatment for their brain cancer, this type of highly coordinated care provides more treatment options, including the newest therapies not available at most hospitals,” said Dr. Michael Vogelbaum, Program Leader of NeuroOncology and Chief of Neurosurgery.
Moffitt’s glioblastoma treatment options include:
As a high-volume cancer center, Moffitt treats many patients for glioblastoma and other rare cancers of the brain and spinal cord. As a result, our neurosurgeons have acquired extensive expertise in utilizing the latest surgical techniques and technologies to remove brain tumors and reduce intracranial pressure that causes symptoms such as headaches, nausea, drowsiness, blurred vision, personality changes and seizures. For instance, real-time imaging technologies such as functional magnetic resonance imaging (fMRI) and MRI tractography can be used during surgery to help the surgeon identify and preserve areas of the brain that are responsible for neurological functions.
Our glioblastoma surgery options include:
5-ALA guided tumor resection
Due to the invasiveness of glioblastoma and the sensitivity of the surrounding brain tissues, it is virtually impossible for a surgeon to safely remove every cancerous cell. However, up to 99% of a tumor is contained within the solid mass. Therefore, by helping a surgeon clearly visualize the boundaries of a tumor, 5-ALA guided tumor resection can provide a significant advantage.
Before surgery, the patient takes the drug 5-aminolevulinic acid (5-ALA) by mouth. Healthy tissues metabolize 5-ALA to hemoglobin, a blood component, but cancerous cells cannot fully process the drug. As a result, 5-ALA accumulates in glioblastomas, causing the cancerous cells to glow or fluorescence as pink under blue light. During the procedure, the surgeon utilizes a specially modified surgical microscope to guide the excision by turning a blue light on and off.
Glioblastomas may be located near critical areas of the brain responsible for speech and motor functions, where imaging may not be sufficiently sensitive. During an awake craniotomy, the patient remains conscious for a portion of the procedure while the surgeon utilizes special mapping techniques to identify areas of the brain that are activated during speech and movement. Specifically, the patient is asked to perform various tasks, such as reading, while the surgeon applies a mild electrical current to the surface of the exposed brain. If the electrical stimulation affects the task, then the surgeon will preserve that area of brain tissue during the tumor excision.
The blood-brain barrier (BBB) prevents most cancer-fighting drugs in the bloodstream from reaching glioblastoma. To bypass the BBB, a surgeon may utilize a direct-delivery approach such as convection-enhanced delivery, which involves the placement of one or more catheters in a brain tumor to slowly pump a medication directly into cancerous tissues.
As a glioblastoma treatment, radiation therapy works by using high-energy beams, such as X-rays or protons, to damage the DNA of cancerous cells. If the damage is not repaired in a timely fashion, the tumor cells will die.
Our radiation therapy options for treating glioblastoma include:
Intensity-modulated radiation therapy (IMRT)
The need to minimize radiation exposure to healthy brain tissues presents a challenge in treating glioblastoma with radiation therapy. Through the use of a computer-controlled linear accelerator, IMRT facilitates the highly precise delivery of radiation. By controlling (modulating) the intensity of the beam, the linear accelerator conforms the radiation to the three-dimensional (3-D) shape of the tumor, focusing a high dose on the cancerous cells with minimal exposure to healthy cells.
A highly precise form of radiation therapy that may be used to treat glioblastoma near critical brain structures, stereotactic radiosurgery delivers narrow energy beams to a tumor from multiple angles. Guided by CT or MRI scans, a physician identifies the exact location of the tumor, then uses a computer to regulate the radiation dose.
Like most other cancerous cells, glioblastoma cells divide very quickly, creating more and more abnormal cells that accumulate and form a tumor. Often used in combination with radiation therapy, chemotherapy involves the systemic use of anticancer drugs to impair or destroy rapidly dividing cells. Chemotherapy medications, which can be injected or taken orally, may include radio sensitizers to enhance the effectiveness of concurrent radiation therapy.
Immunotherapy is a potential glioblastoma treatment that capitalizes on the power of the body’s immune system by helping it to recognize, target and destroy cancerous cells. One approach involves the use of “checkpoint inhibitors.” These drugs work by altering certain molecules known as “immune checkpoints,” which keep the immune system from becoming overactive and attacking healthy tissues. Tumor cells often over-produce immune checkpoints; as a result, they are able to shield themselves from the immune system’s cancer-fighting T-cells. Checkpoint inhibitors can effectively “release the brakes,” thereby exposing the rogue cancer cells to the T-cells.
Medically Reviewed by Dr. Michael Vogelbaum, Program Leader, Department of Neuro-Oncology and Chief of Neurosurgery.
To learn more about Moffitt’s approach to glioblastoma treatment or to make an appointment with a specialist in our Neuro-Oncology Program, please call 1-888-663-3488 or complete our new patient registration form online.