Brain cells can sometimes divide uncontrollably to form a tumor within the brain, the covering of the brain, or on the nerves in the brain. This type of tumor is called a primary brain tumor and is different rom secondary brain tumors, or those that occur by the spread (or metastasis) of tumors from other organs in the body.
Whether benign (noncancerous) or malignant (cancerous), all patients with brain tumors require immediate attention. At Yale Medicine, our experienced doctors use their expertise and state-of-the-art equipment to diagnose, manage and treat brain tumors.
What are the different types of primary brain tumors?
We classify primary brain tumors by type and the World Health Organization (WHO) grade.
Types of primary tumors are classified by the cell from which they originate. A glioma, for instance (which is the focus of this discussion) is a common type of primary brain tumor. Originating from specialized cells of the central nervous system called astrocytes or oligodendrocytes, this type of brain tumor is called astrocytomas or oligodendrogliomas.
Grading of primary brain tumors helps distinguish their clinical behavior and provide insight with regards to tumor growth, recurrence and prognosis.
With regards to gliomas, a WHO Grade 1 tumor is the most benign and referred to as pilocytic astrocytoma. These are more commonly encountered in children.
Grade 2 gliomas are often referred to as “infiltrative glioma” or “low-grade gliomas” (LGGs) given their slow, infiltrative growth patterns.
Grades 3 and 4, anaplastic glioma and glioblastoma, or glioblastoma multiforme (GBM), respectively are considered “high-grade gliomas" (HGGs) because they behave more aggressively with a faster growth rate and are considered malignant, or cancerous. High grade gliomas can arise from low grade gliomas, or may be what's called “de novo” (meaning they arise primarily as a high grade tumor) and have specific mutations related to each.
What are symptoms of primary brain tumors?
Symptoms of brain tumors depend on several factors, including the location and size of the tumor. For instance, if a tumor is situated near the motor part of the brain, the patient may experience weakness on one side of the body. If the tumor is near the speech area, the symptoms may include difficulty speaking or understanding language.
Even small brain tumors can influence brain function in the region where they have grown, depending on the function of the brain the tumor involves. Primary brain tumors can also cause seizures, headaches, nausea, and vomiting.
How is a brain tumor diagnosed?
There are no regular screenings for brain tumors (unlike cancers of the prostate or colon). Therefore most brain tumors are diagnosed in patients who already have symptoms or signs of growth; less commonly, brain tumors are found by chance after a head trauma.
Doctors often diagnose primary brain tumors by performing a computerized tomography (CT) scan or magnetic resonance imaging (MRI).
A full medical exam is also performed and a detailed medical history is taken in order to help our doctors plan the best course of management. Sometimes, as is the case with brain tumors near “eloquent” parts of the brain with important function (i.e. speech and motor areas), a more specialized MRI allows us to better understand the relationship between the tumor and the function in the brain. This can be invaluable for surgical planning.
How do we treat a low-grade (Grade 1 to 2) tumor?
Most brain tumors occur sporadically, or by chance without a specific cause. Some can be associated with syndromes, but this typically involves people who already have multiple and different types of tumors.
Nonetheless, primary brain tumors have specific underlying genetic mutations and Yale researchers are world renowned for understanding these abnormalities. By screening a tumor’s entire genetic code, we can better decide on therapy and personalize it to each individual. While standard of care (i.e. proven treatment) for primary brain tumors is used in all patients at Yale Medicine, exciting clinical trials are also available, giving the best chance for a successful outcome.
“While people may be concerned about environmental risk factors for brain tumors, there is currently not enough evidence to support a link between cell phone radiation and brain cancer, for instance,” says Yale Medicine neurosurgeon Jennifer Moliterno, MD.
How do you treat a high-grade (Grade 3 to 4) tumor?
"At Yale Medicine, we treat every and any type of brain tumor in every and any patient," says Dr. Moliterno. Each patient is evaluated quickly and thoroughly. All cases are presented at our multidisciplinary tumor board, where a team of brain tumor specialists (neurosurgeons, neurologists, radiation specialists, pathologists, radiologists, etc) work collaboratively to develop a treatment plan that provides the best possible care and also takes into consideration the patient's wishes.
Most brain tumors are treated surgically, often using stereotactic image-guided biopsy for diagnosis and/or microsurgical resection (i.e. removal of as much tumor as safely possible). Surgical removal can help control or improve a patient’s symptoms. "Various factors dictate which approach is taken, but it is our practice to try to be as aggressive as possible because the amount of tumor removed correlates with patient outcome, by which I mean, the more tumor removed, the better outcome," explains Dr. Moliterno.
Further, she notes, Yale Medicine neurosurgeons are highly trained, specialized surgeons dedicated to only treating brain tumors in a surgical setting with state-of-the-art resources. "We use the most advanced equipment and unparalleled expertise, allowing us to be as aggressive and as safe as possible when removing brain tumors," she says.
Yale Medicine is unusual in having dedicated experts involved in every brain tumor surgery, offering specialized neuro-monitoring of motor and nerve function, plus the ability to perform comfortable “awake” surgery when it is indicated and the use of an intraoperative MRI during the operation.
In addition to making an accurate diagnosis, the goal is to remove as much tumor as possible while still preserving neurological function. “More specialized training and techniques allows our surgeons to remove tumors other surgeons deem 'inoperable,'" says Dr. Moliterno. She adds, "Also, we are the only hospital in CT to offer laser thermocoagulation for treating brain tumors that are too dangerous to remove."
Though it's unusual, some people whose brain tumor is incidentally found and not presenting any symptoms may be followed closely with MRIs. In these cases, notes Dr. Moliterno, "our doctors have the expertise to make this judgment and can intervene when and if necessary.
What happens after surgery?
Most patients with primary brain tumors, such as gliomas, will require some additional therapy such as radiation and/or chemotherapy. “I tell patients our reason for being as aggressive as we can with surgery is because the less tumor in the brain for the chemotherapy and radiation to work on, the better outcome for the patient,” says Dr. Moliterno.
Yale Medicine patients also have a distinct advantage over those treated at other centers in the region, she notes. "We are not only one of the nation’s largest centers for researching mutations, we also offer many exciting clinical trials relating to medication, chemotherapy, treatments after surgery, and even surgical drug injections." (Often these therapies can be delivered in centers close to patients' homes.)
“It is important for patients to be treated at a center like Yale Medicine, where physicians are up-to-date on the best treatment options for patients with primary brain tumors and have close collaborations with community physicians,” says Dr. Moliterno. “We offer a support group for our patients because we understand the challenges of a brain tumor diagnosis. That said, we are here every step of the way to offer support.”
What makes Yale Medicine’s approach to treating brain tumors unique?
Yale Medicine has a one-of-a-kind group of specialized experts who are solely dedicated to treating brain tumor patients. These highly experienced neurosurgeons have access to the most advanced technology available.
For instance, Yale Medicine is one of the few centers internationally with intraoperative MRI, giving neurosurgeons access to imaging during surgery to focus on removing as much of a tumor as we can. We also have expertise with monitoring the patient’s important functions, such as speech and strength, during surgery with the goal of removing as much tumor as possible while preserving these functions.
Additionally, every case is presented before our multidisciplinary tumor board, consisting of surgeons, oncologists, pathologists, and radiologists who meet to identify the best, most comprehensive treatment plan.
We're not only one of the nation’s largest centers for researching mutations, we also have access to many exciting clinical trials relating to medication, chemotherapy, treatments after surgery, and even, occasionally, surgical methods.