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Surgery
Source: Central Nervous System Tumors Treatment (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: March 28, 2025 · Captured 2026-09-09.
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Context: Treatment Option Overview for Primary CNS Tumors / Primary CNS Tumors
For most types of CNS tumors in most locations, complete or near-complete surgical removal is generally attempted, within the constraints of preserving neurological function and the patient's underlying health. This practice is based on observational evidence that survival is better in patients who undergo tumor resection than in those who have closed biopsy alone.[2,3] The benefit of resection has not been tested in randomized trials. Selection bias can enter into observational studies despite attempts to adjust for patient differences that guide the decision to resect the tumor. Therefore, the actual difference in outcome between radical surgery and biopsy alone may not be as large as noted in the retrospective studies.[3]
An exception to the use of resection is the case of deep-seated tumors such as pontine gliomas, which are diagnosed on clinical evidence and treated without initial surgery approximately 50% of the time. In most cases, however, diagnosis by biopsy is preferred. Stereotactic biopsy can be used for lesions that are difficult to reach and resect.
The primary goals of surgical resection include:[4]
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To establish a histological diagnosis.
To reduce intracranial pressure by removing as much tumor as is safely possible to preserve neurological function.
Total elimination of primary malignant intraparenchymal tumors by surgery alone is rarely achievable. Therefore, intraoperative techniques have been developed to reach a balance between removing as much tumor as is practical and preserving functional status. For example, craniotomies with stereotactic resections of primary gliomas can be performed in cooperative patients while they are awake, with real-time assessment of neurological function.[5] Examples of intraoperative neurological assessment include:
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Resection proceeds until either the magnetic resonance imaging (MRI) signal abnormality being used to monitor the extent of surgery is completely removed or subtle neurological dysfunction appears (e.g., a slight decrease in rapid alternating motor movement or anomia).
When the tumor is located in or near language centers in the cortex, intraoperative language mapping can be performed by electrode discharge-induced speech arrest while the patient is asked to count or read.[6]
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As is the case with several other specialized operations [7,8] in which postoperative mortality has been associated with the number of procedures performed, postoperative mortality after surgery for primary brain tumors may be associated with hospital and/or surgeon volume.[9] The following results were reported after an analysis of the Nationwide Inpatient Sample hospital discharge database for the years 1988 to 2000, which represented 20% of inpatient admissions to nonfederal U.S. hospitals:[9]
Large-volume hospitals had lower in-hospital mortality rates after craniotomies for primary brain tumors (odds ratio [OR], 0.75 for a tenfold higher caseload; 95% confidence interval [CI], 0.62–0.90) and after needle biopsies (OR, 0.54; 95% CI, 0.35–0.83).
Although there was no specific sharp threshold in all-cause mortality outcomes between low-volume hospitals and high-volume hospitals, craniotomy-associated in-hospital mortality was 4.5% for hospitals with 5 or fewer procedures per year and 1.5% for hospitals with at least 42 procedures per year.
In-hospital mortality rates decreased over the study years (perhaps because the proportion of elective nonemergent operations increased from 45% to 57%), but the decrease was more rapid in high-volume hospitals than in low-volume hospitals.
High-volume surgeons had lower in-hospital patient mortality rates after craniotomy (OR, 0.60; 95% CI, 0.45–0.79).
As with any study of volume-outcome associations, these results may not be causal because of residual confounding factors such as referral patterns, private insurance, and patient selection, despite multivariable adjustment.
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Preserved source evidence · Not medical advice