Among patients undergoing surgery for glioma (a type of brain tumor), a less extensive approach to surgery and brain mapping still allows for preservation of language function in a large proportion of patients. These results were published in the New England Journal of Medicine.
Glioma is a cancer that originates in the central nervous system (CNS), which includes the spinal column and the brain. Glioma arises from glial cells, which are cells comprised of connective tissue that surround and provide support to nerve cells.
Initial treatment of brain tumors often involves surgery. The goal of surgery is to remove as much of the tumor as possible while preserving important brain functions such as language.
To minimize language problems after surgery, patients may undergo language mapping during surgery. In this procedure, electrodes are applied to different areas of the brain while the patient is awake. The patient's response to questions during this process allows physicians to identify areas of the brain that are important for language.
In a common approach to language mapping, a large area of the skull is removed in order to identify positive sites (sites that are important for language). An alternative approach is to remove a smaller portion of the skull and to rely on negative sites (sites that are not important for language) to guide the extent of the surgery.
To explore how well language is preserved with the negative brain mapping technique, researchers describe the results for 250 glioma patients. Before surgery 159 patients (64%) had intact speech.
- One week after surgery, 77.6% of patients retained their baseline language function, 8.4% of patients had a decline in language function, and 14% of patients had a new speech deficit.
- By six months after surgery, only 4 of 243 surviving patients (1.6%) had a permanent postoperative language deficit.
- Complete removal of all detectable cancer was achieved in 59.6% of patients.
- An interesting finding of the study was that the location of language function within the brain was found to vary widely across individuals.
The researchers conclude: "Our findings suggest that a tailored craniotomy in conjunction with negative language mapping can be relied on to maximize resection and minimize morbidity when gliomas within or near language pathways are removed."
Reference: Sanai N, Mirzadeh Z, Berger MS. Functional outcome after language mapping for glioma resection. New England Journal of Medicine. 2008;358:18-27.