Gamma Knife Treatable Conditions
A safe, effective alternative to open-skull surgery, Gamma Knife radiosurgery can successfully treat patients with benign and malignant brain tumors, vascular disorders of the brain, and pain and other neurological disorders.
Benign brain tumors
Malignant brain tumors
Vascular disorders of the brain
Pain and other neurological disorders
The information below is taken through data available from July 1999 through June 2006.
Benign brain tumors:
- acoustic neuroma (tumor on the nerve leading to the inner ear)
- pituitary adenomas (tumor of the pituitary gland)
- meningiomas (tumor of the protective membranes around the brain and spinal cord)
- chordomas (tumor at the base of the skull or lower spine)
- hemangioblastomas (tumor of the nervous system)
- craniopharyngioma (tumor at the base of the skull)
- and other cranial nerve schwannoma
At Lancaster General Health, the Gamma Knife team has treated more than 137 acoustic neuromas – a generally slow-growing, benign tumor that can cause hearing loss, dizziness, tinnitus, and problems with balance, as it presses on the nerve leading to the inner ear. In 97 percent of the 137 patients treated, Gamma Knife radiosurgery either halted tumor growth or induced regression.
Meningiomas are slow growing and generally benign tumors that arise from the brain lining tissue. In the 218 patients with meningioma treated by Lancaster General Health’s Gamma Knife team, 95 percent of them had their tumor growth stopped.
The Lancaster General Health team has also treated recurrent and residual benign pituitary tumors with the Gamma Knife. A tumor in the hormone-secreting pituitary gland, responsible for regulating many functions performed by other organs in the body, can affect the entire body. Though the traditional treatment of choice is transsphenoidal removal, the Gamma Knife works well with patients with recurrent and residual tumors, and especially in patients whose tumor extends laterally into the cavernous sinus area where traditional surgery is not feasible. Of the 47 patients treated at Lancaster General Health with these conditions, tumor growth was halted in 46.
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Malignant brain tumors:
- metastatic tumors (spread from other parts of the body, especially from lung, breast, and kidney cancers, and melanoma)
- malignant gliomas (these include astrocytic and oligodendroglial tumors, and the very aggressive glioblastomas)
- and other primary malignant brain tumors (including ependymomas, craniopharyngiomas, pituitary tumors, pineal gland tumors, and primary germ cell brain tumors)
Brain metastasis is the spread of malignant cells from one area of the body to the brain tissue and is the most common type of brain tumor. Metastasis to the brain may originate from various different primary tumor locations including lung, breast, skin, kidney and colon. The most common source of brain metastases in males is lung cancer and in females is breast cancer.
Metastatic tumors are the most common malignant brain tumors treated with gamma knife radiosurgery. They can arise anywhere in the brain – appearing as a single lesion or as more than one. The primary sources of most cancers that metastasize to the brain are lung, breast, kidney and melanoma, although any type of malignancy may spread to the brain. Single and multiple brain metastases are treatable with the Gamma Knife, but at Lancaster General Health, the team generally limits treatment to patients with fewer than five metastatic tumors. Depending on the patient and the conditions, treatment regimens may warrant Gamma Knife alone or in combination with surgery, radiation therapy, or chemotherapy. Many patients with brain metastases require repeat Gamma Knife treatment as they develop new tumors.
As of June 2006, 350 patients with a variety of metastatic tumors have undergone Gamma Knife radiosurgery at Lancaster General Health with excellent results for the majority. For 70 to 80 percent of those patients, tumor progression slowed or halted. Unfortunately, most patients with metastatic cancer eventually succumb to the primary cancer, but Gamma Knife radiosurgery may prolong survival and significantly improve the quality of life.
Gliomas are tumors that arise in the brain tissue itself, glial tissue (as opposed to metastatic brain tumors which arise from other body organs and travel to the brain). They are the most common type of brain tumor and graded based on their level of malignancy. As the grade of the tumor increases, the tumor becomes more aggressive.
The Lancaster General Health Gamma Knife team treated 78 patients with primary brain tumors, mainly high-grade gliomas. In these ominous lesions, the Gamma Knife is used to boost external beam radiation, and the benefits in this group of patients are limited.
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Vascular disorders of the brain:
- arteriovenous malformations (AVM) (an incorrectly formed bundle of blood vessels)
- cavernous malformations (cluster of abnormal blood vessels)
Arteriovenous malformations (AVMs) usually develop during the developmental stages of a fetus but usually do not pose any problems until the person approaches their 20s or 30s when the malformation causes the blood flow to cease and form pockets of blood. These pockets may enlarge over time and cause the patient difficulties such as a severe headache, seizure or stroke. There is also the possibility that these pockets will rupture. Treatment of AVM’s is used to reduce this risk of rupture and reduce the potential side effects from the rupture or the enlargement of the vessels.
These two types of vascular disorders put patients at a risk for intracranial hemorrhage – a condition Gamma Knife radiosurgery works to resolve. Within two to three years of treatment, Gamma Knife radiosurgery tends to obliterate these malformations. The Lancaster General Health team had treated 22 patients with true arteriovenous malformations and 14 patients with cavernous angiomas – all with excellent results. None of these patients had suffered a recurrent hemorrhage.
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Pain and other neurological disorders:
- trigeminal neuralgia (a painful disease of the facial nerves)
- epilepsy (a condition that involves repeated seizures)
- and severe disabling tremors (from conditions like Parkinson’s disease and other movement disorders)
Trigeminal Neuralgia is a disorder of the trigeminal nerve that causes sudden onset of intense, acute face pain most often near the nose, lips or eyes. This pain may come and go, with no treatment necessary. If treatment is necessary, medications such as carbamazepine, gabapentin, and baclofen may successfully control the pain. Unfortunately, sometimes the pain will become worse and cease to be controlled with medication. The Gamma Knife can deliver a high dose of radiation directly to the nerve, which often alleviates pain.
At Lancaster General Health, the Gamma Knife team has treated 193 patients with trigeminal neuralgia. Facial pain resolved in 55% of patients and 25% improved within three weeks to three months of treatment. Although transient or permanent facial numbness occurred in about 10% of patients, trigeminal neuralgia
is so painful that most patients willingly accept this risk. Patients with recurrent pain may undergo repeat Gamma Knife radiosurgery, and approximately 60% of patients in this population ultimately achieved resolution of their pain.
Use of the Gamma Knife is expanding. The Lancaster General Health Gamma Knife team expects the technology to have a future role in the management of treatment-resistant epilepsy and the disabling tremors from Parkinson’s disease.
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