Cerebral metastases are the most common brain tumors that are clinically encountered, making up just over half of brain tumors. The annual incidence of new cases is over 100,000. Cerebral metastasis is seen in 20-40% of cancer patients. The increasing number of new cases may be a consequence of extended survival of cancer patients due to improvements in the treatment of systemic cancer, as well as detection with enhanced imaging techniques with CT and MRI. These lesions can present as solitary lesions or as multiple lesions disseminated throughout the brain, typically occurring at the grey-white junction. The most common locations from which these lesions metastasize include the lung, breast, kidney, gastrointestinal system, and skin (melanoma). Approximately 10% come from an undetermined source. 

Intracranial metastases may involve either the cerebrum or cerebellum, or the cerebrospinal fluid pathways, as in carcinomatous meningitis. The diagnosis of brain metastases is based on the patient’s history, neurological examination, and diagnostic imaging studies. A lumbar puncture for cerebrospinal fluid cytology is useful in diagnosing carcinomatous meningitis. Head magnetic resonance imaging is the most sensitive and specific imaging modality available.

The clinical symptoms can vary widely from patients being asymptomatic, discovering their tumors incidentally, to severe neurological deficits and dysfunction. Symptoms are related to increased intracranial pressure from mass effect or from blockage of the cerebrospinal fluid pathways leading to hydrocephalus, or focal irritation or disruption of brain function. Headache is the most common symptom occurring in about 50% of patients, followed by nausea and vomiting. Focal neurological deficits such as facial or extremity weakness or cranial nerve dysfunction are also frequently seen. Patients can develop cognitive impairment and mental status changes, manifested by confusion or disorientation, or personality change. New onset seizures are less common, presenting in approximately 15% of cases. 

A full metastatic workup is indicated in cases when metastatic disease is suspected prior to obtaining tissue from a brain lesion. The workup usually includes a chest x-ray, computed tomography of the chest, abdomen, and pelvis, fecal occult blood test, radionuclide bone scan, mammogram in women, and a PET scan. Up to 10% of cases will be undetermined with no primary cancer identified despite a thorough evaluation.

No single form of treatment is curative. Treatment strategies aim to provide tumor growth control to enhance optimal survival and quality of life. As such, most treatments are largely palliative and not curative due to the very nature of the systemic involvement of the metastatic disease process. Patients are typically evaluated by a team of specialists including medical oncologists, radiation oncologists, and neurosurgeons. Working together, the team formulates specific treatment plans for every individual patient. Therapeutic decision-making depends on multiple factors including, the patients neurological status, extent of systemic disease, extent of neurological disease, and location of brain lesions. Multimodality treatment plans may include a combination of surgery, chemotherapy, and/or radiation. Most of the time, patients will undergo a specific combination of these treatments based on the type of primary lesion that is encountered in order to maximize clinical outcomes and survival.

Some brain lesions that were previously considered inoperable based on their location may now be amenable to surgical resection using innovative intraoperative imaging and monitoring techniques. Brain biopsy using a stereotactic system is used only for diagnostic purposes. We offer both of these services at Central Florida Regional Hospital. Additionally, not all lesions respond to chemotherapy or conventional radiation treatment. New advancements in stereotactic radiosurgery technology are currently offered at Central Florida Regional Hospital, which houses a CyberKnife stereotactic radiosurgery unit, one of just a few in central Florida.

The CyberKnife allows the neurosurgeon and the radiation oncologist to work together in targeting brain tumors with a very high degree of precision while minimizing the amount of radiation exposure to the surrounding normal brain structures. It can also be used to target tumors elsewhere in the body or spine. The system utilizes a robotic tracking system that minimizes the discomfort associated with other stereotactic radiosurgery systems that require placement of a stereotactic head ring via skull pin fixation.

There have also been advancements in the use of chemotherapeutic agents. Temozolomide is now being used in combination with other agents such as etoposide, gemcitabine, cyclophosamide, and doxorubicin, improving efficacy of treatment. The strategy and delivery of these agents are directed by the medical oncologist. In conclusion, brain metastasis is a common clinical problem encountered by neurosurgeons. However, there are many strategies and treatment options available to patients to enhance their quality of life and survival.

Dr. Rafael Allende joined The NeuroHealth Sciences Center at Central Florida Regional Hospital on April 1st, 2008. Dr. Allende previously practiced in Rochester, New York, and held the position of Assistant Professor at the University of Rochester. He received his medical degree from Harvard Medical School.

While at Harvard he completed a one year research fellowship in the treatment of brain tumors. He completed his internship in general surgery and his residency in neurological surgery at the University of Rochester, where he joined the faculty upon the completion of his training until relocating to Sanford in April 2008.

Dr. Allende specializes in general neurosurgery with a special interest in spinal surgery, including minimally invasive procedures, disc arthroplasty, and the latest innovative procedures in carefully selected patients.

Dr. Rafael Allende
NeuroHealth Sciences Center
200 N. Mangoustine Ave, Sanford, Fl 32771
(407) 833-7505

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