Brain & Spinal Tumor Treatment Options
Surgery has been and remains the most effective treatment for all high-grade brain tumor patients. While patients with low-grade tumors can be cured occasionally by the surgical removal of the disease, high-grade tumors cannot be cured by surgery alone. However, studies clearly demonstrate that the removal of more than 90% of a high-grade tumor substantially improves patient survival rates. And, when combined with aggressive and effective post-surgical therapy, surgery can result in cure for some patients, including those with glioblastoma multiforme (GBM).
The goal of CNI neurosurgeons is to remove as much tumor as possible without causing unacceptable neurological deficits. Advanced diagnostic tools allow neurosurgeons to determine the full extent of the tumor prior to surgery (via an MRI spectroscopy) and the risks for unacceptable neurological problems as a result of the surgery (via a functional MRI).
Types of surgery include the following:
Some patients have tumors that develop in areas of the brain that are important regions for the control of speech, language and other neuropsychological functions. In order to preserve as much function as possible when removing these brain tumors, doctors may decide to do part of the operation while the patient is awake. If an “awake” procedure is recommended, care during the surgery will involve one or more neurosurgeons, an anesthesiologist, a neuropsychologist, a neurologist and several operating room technicians. In these procedures, patients typically experience minimal discomfort because the potentially painful part of the operation is done while the patient is asleep and under general anesthesia.
Here’s a look at the progression of an “awake” procedure:
- Patients are awake for a period lasting between 30 minutes and two hours.
- After the patient becomes alert, the neuropsychologist begins testing speech, language, memory, or other neuropsychological tasks the person will have practiced earlier that day in the hospital or at the doctor’s office.
- The specific tasks used during an operation will depend upon the nature and location of the lesion and what functional areas of the brain are likely to be involved in an individual’s surgery.
- Many people do not recall anything about having been awake during the operation, though some recall parts of the process.
If your doctor recommends an awake craniotomy, you will be fully informed of what to expect in your specific situation.
Functional mapping techniques are used to “map” areas of the brain that control key functions, such as language and sensory-motor functions. These techniques are used to preserve as much neurological function as possible for a patient while also enabling to surgeon to optimize tumor removal. Functional mapping techniques include:
- Functional MRI: MRI scanning is used to map functional areas of the brain using special software.
- Pre-operative functional mapping: Requires an operation to place a grid of electrodes on the surface of the brain followed by a period of evaluation of brain function outside the operating room by a specially qualified neurologist. The brain is directly stimulated and the responses are recorded so that the surgeon will have an actual map of the functions of the area around the tumor. This information will be used to plan the best surgical approach.
- Intraoperative functional mapping: Specific areas of the brain are electrically stimulated during an operation to determine where the functional areas are so surgeons can minimize any clinical deficits. This technique is usually performed while the patient is under general anesthesia and unconscious, but occasionally this requires that the patient be awakened for language testing. A CNI neurologist and, if necessary, a neuropsychologist will assist the neurosurgeon in this specialized technique.
All functional mapping techniques involve cooperation between the Brain & Spinal Tumor, neurologists and the staff of CNI’s epilepsy services.
This relatively new technique is not universally available to neurosurgeons, but is used routinely at CNI. Using modern imaging technology, the neurosurgeon can place a probe anywhere in the patient’s brain during surgery and see close-up, three-dimensional images of the brain and tumor on a screen in the operating room. This enables the neurosurgeon to continue removing tumor in situations where, without frameless stereotaxy, surgery would have to be discontinued.
As a result of this valuable technology, our patients have a high percentage of complete, or near complete, removal of their tumors. In the near future, CNI hopes to improve upon this technology further by mapping areas of the brain that contain tumor, which currently can only be identified through biochemical analysis of the brain. By doing so, neurosurgeons may be able to remove even more tumor than is currently possible.
A laser is a form of light energy that is powerful and targeted enough to cut tissues more precisely than other techniques in certain situations. CNI neurosurgeons routinely use lasers during surgeries that require them to come very close to important structures. An operative microscope is used during these procedures to ensure pinpoint precision.
Radiation therapy has been available for the treatment of central nervous system tumors for many years, but recently, the level of sophistication utilized by radiation oncologists has improved markedly. Radiation in relatively high doses is a proven effective treatment for central nervous system tumors and can significantly prolong patient survival. However, because radiation can also affect normal brain tissue, the amount of radiation used must be limited. Recently, an emphasis has been placed on researching techniques that allow more aggressive treatment of tumors while minimizing the exposure of normal brain to radiation. Successful achievement of this goal will increase survival while reducing both short and long term effects of the treatment.
It should be noted that while radiation therapy is effective, it is seldom curative on its own. At CNI, our current approach is to administer chemotherapy in combination with radiation therapy to capitalize on the possible “radiosensitizing effects” of the chemotherapeutic agents, while ensuring that neither important modality is delayed.
Gamma Knife (Stereotactic Radiosurgery)
Often referred to as “knifeless surgery,” Gamma Knife surgery (an advanced form of stereotactic radiosurgery) delivers pinpointed doses of radiation to treat brain tumors and other neurological diseases with minimal damage to normal tissue. Highly targeted and minimally invasive, this procedure is usually given in one daily treatment and has been used in situations where a tumor cannot be eliminated by surgery or by chemo-radiation therapy. This technique is somewhat limited by the size and shape of the tumor, but it is frequently used with significant benefit to our patients. The Gamma Knife also has proven effective for the treatment for low-grade tumors in locations where they cannot be safely removed surgically or tumors that have spread to the brain from other parts of the body.
CNI employs an aggressive approach to post-surgical care of patients with primary high-grade gliomas. Aggressive treatment is appropriate since the greatest threat to the quality of life and survival is posed by the tumor itself, not the treatment. Our aggressive approach emphasizes the use of combination chemotherapy plus biological therapy, both during and following standard radiation therapy.
The rationale for using combination chemotherapy rather than a single agent chemotherapy (the current community standard is single agent temozolomide) is simple: there is no precedent for the predictable curability of human cancer with any single chemotherapy drug, no matter how effective the drug might be.
This dictum was recently reiterated by DeVita in his authoritative textbook entitled “Cancer, Principles and Practice of Oncology.” At CNI, we also believe that the results achieved with single agent Temodar, published recently by Stupp, et al., can be improved upon by adding other drugs to the Temodar. We published our results in the journal “Neuro-oncology” in the summer of 2005 and presented them in Scotland at the Annual Meeting of the World Federation of Neuro-oncology.
A minority of adult patients with primary brain tumors have low-grade tumors. These tumors include grade II astrocytoma, grade II oligodendroglioma, and a mixture of both. For low-grade tumors where there is no evidence of early evolution to high-grade, surgery can be curative. Unfortunately, despite the advances in surgery that allow a higher number of surgical cures and a greater likelihood of successful surgery (greater than 90% removal), most patients with low-grade tumors are left with residual disease following their surgery. Perhaps this is because these tumors present more insidiously over longer periods of time before the symptoms lead to the diagnosis and, therefore, the tumors are larger once discovered. The occurrence of residual disease has become more apparent with recent advances in imaging, especially MRI spectroscopy.
Treatment of these patients is controversial. It has not been established in the medical literature that radiation is indicated for patients prior to disease progression, although there is evidence that these tumors respond to radiation. The role of chemotherapy is even less established despite recent reports that demonstrate that chemotherapy regimens such as PVC (procarbazine, CCNU, and vincristine) can produce responses in low-grade tumors, especially oligodendrogliomas.
At CNI, we offer chemotherapy to patients with incompletely removed low-grade tumors in order to reduce the incidence of relapse and evolution to more aggressive (high-grade) tumors. We have used a modification of PVC in which procarbazine has been replaced by the more tolerable and efficacious drug, Temodar. In addition, the drug carboplatin has been added in order to reduce exposure to CCNU, which has substantial cumulative toxicities. Over the last 10 years, we have used this approach to treat nearly 100 patients
Following completion chemotherapy, patients undergo a final biological therapy phase in which they will take the drug tamoxifen in high doses plus or minus the drug thalidomide. These drugs are not chemotherapeutic agents. They are, however, agents which have been shown to have a beneficial effect on malignant brain tumors, either stopping growth or severely limiting their ability to progress.