Should all brainstem tumors be operated on?

Should All Brainstem Tumors Be Operated On?

No, brainstem tumors should NOT always be operated on—surgical resection is only indicated for specific tumor types and clinical scenarios, while diffuse pontine tumors and stable asymptomatic lesions should be managed conservatively. 1, 2

Absolute Contraindications to Surgery

• Diffuse midline gliomas (DMG) of the pons are NOT surgical candidates and should proceed directly to radiotherapy for symptom control 1
• Deep intra-axial brainstem metastases are rarely approached surgically unless exophytic and laterally accessible 1
• Stable, asymptomatic brainstem lesions without neurological deficits should be managed with surveillance imaging rather than empiric surgery 2
• Diffuse intrinsic brainstem tumors in children uniformly have malignant histology, show no surgical benefit, and result in death within 12-18 months regardless of intervention 3

Clear Surgical Indications

Large Tumors with Mass Effect

• Brainstem compression requiring decompression is the primary indication for surgery, as this is the only modality that can rapidly relieve pressure on critical structures 1, 4
• Posterior fossa tumors larger than 3 cm with significant edema and incipient brainstem or fourth ventricular compression should undergo open surgery rather than radiosurgery 1, 4
• Even incomplete resection for decompression is justified when followed by stereotactic radiosurgery or observation for residual tumor 1

Focal and Exophytic Tumors

• Focal, cystic, and cervicomedullary tumors are the most amenable to surgical resection with favorable outcomes 5, 6, 3
• Exophytic medullary tumors presenting dorsally comprise the most benign subgroup, where total removal enhances survival and quality of life 6
• Focal tumors and cervicomedullary tumors frequently harbor low-grade histology and demonstrate long-term survival (1-6 years postoperatively) after resection 3

Diagnostic Uncertainty

• Surgery is indicated when tissue diagnosis is needed and the lesion is surgically accessible, particularly when imaging or clinical presentation is atypical for the presumed diagnosis 1

Tumor-Specific Considerations

Pediatric High-Grade Gliomas

• Maximal safe resection with goal of complete removal is recommended for all non-pontine pediatric diffuse high-grade gliomas 1
• Gross total resection is the strongest predictor of overall survival and event-free survival in this population 1

Ependymomas

• Surgery is the crucial first step, with extent of resection being the most significant predictor of outcome 1
• Posterior fossa ependymomas involving the ponto-cerebellar region may require incomplete resection due to involvement of lower cranial nerves and brainstem, but second-look surgery should be considered 1

Vestibular Schwannomas

• Large tumors (Koos grade IV, >3 cm) with brainstem compression require surgical decompression as the only option 1
• Tumor mass reduction by incomplete resection followed by radiosurgery or observation is valid when cranial nerve preservation is critical 1

Critical Surgical Outcomes and Risks

Expected Complications

• Serious postoperative complications occur in approximately 50% of brainstem tumor surgeries, including bilateral ptosis, impaired swallowing, coughing reflex loss, and aspiration pneumonia risk 5
• Neurological deterioration is common in adults with intrinsic brainstem tumors and, unlike pediatric patients, is often irreversible 7
• Immediate postoperative mortality ranges from 8-12% in surgical series of intrinsic brainstem tumors 5, 7

Prognostic Factors

• Total or subtotal removal (>50% resection) can be achieved in approximately 50-75% of selected cases 5, 6
• Five-year survival from symptom onset is 37.5% for intrinsic brainstem tumors, with median survival of 11 months after surgery 7
• Low-grade tumors (gangliogliomas, focal astrocytomas) demonstrate stable disease after partial resection without clear tumor growth at long-term follow-up 8

Management Algorithm

For diffuse pontine tumors: Proceed directly to radiotherapy without surgery 1

For focal/exophytic tumors with symptoms: Pursue maximal safe resection via posterior fossa approach 5, 6, 3

For large tumors with brainstem compression: Surgical decompression is mandatory, even if incomplete resection is anticipated 1, 4

For stable asymptomatic lesions: Implement surveillance with MRI at 3-6 month intervals initially, extending to annual imaging if stability continues 2

For tumors <3 cm without mass effect: Consider stereotactic radiosurgery over open surgery if diagnosis is established 1

Common Pitfalls to Avoid

• Never perform empiric radiotherapy or surgery on stable, asymptomatic brainstem lesions without tissue diagnosis, as radiation carries significant delayed toxicity risk 2
• Do not attempt stereotactic biopsy of deep brainstem lesions solely for diagnostic purposes when lesions are stable and asymptomatic, given the risk of permanent neurological deficits 2
• Avoid surgery for diffuse intrinsic pontine gliomas in children, as all such patients have malignant tumors with uniformly poor outcomes regardless of surgical intervention 3
• Recognize that adult intrinsic brainstem tumor surgery carries questionable benefit despite offering histopathological confirmation, as neurological deterioration is common and often permanent 7