What are the options for systemic treatment in central neurocytoma?

Systemic Treatment in Central Neurocytoma

Systemic chemotherapy has a limited and poorly defined role in central neurocytoma, reserved primarily for recurrent disease after surgery and radiation have been exhausted, with temozolomide being the most commonly reported agent despite lack of robust evidence for long-term efficacy.

Primary Treatment Paradigm

Central neurocytoma is a rare WHO grade II intraventricular tumor comprising 0.25-0.5% of brain tumors, and surgery remains the definitive primary treatment 1, 2. The treatment hierarchy is clear:

• Maximal safe surgical resection is the cornerstone of management and confers the best long-term outcome 1, 3
• Complete resection can be achieved in approximately half of cases and provides favorable prognosis 4, 2
• Radiation therapy (conventional external beam or stereotactic radiosurgery) is indicated for subtotal resection or recurrence 1, 3

Role of Systemic Chemotherapy

Chemotherapy is not part of standard initial management for central neurocytoma 1, 2. The evidence base is extremely limited:

Current Evidence for Chemotherapy

• Only 40 cases total (including 39 from literature review plus one institutional case) have been reported using chemotherapy for central neurocytoma 5
• Marked heterogeneity exists in chemotherapy regimens used, with no standardized approach 5
• Long-term responses to chemotherapy have not been reported 1

Temozolomide as the Most Common Agent

• Temozolomide is the most frequently incorporated agent in recurrent disease, with only 9 total reported cases 5
• TMZ is typically used in the setting of tumor recurrence when surgical and radiation options are exhausted 5
• The role of temozolomide merits further study but remains investigational 5

Treatment Algorithm for Recurrent Disease

When central neurocytoma recurs, the approach should follow this hierarchy:

1. Re-operation should be considered first if the procedure can be safely performed 1
2. Radiation therapy (conformal or stereotactic radiosurgery) for smaller residual volumes or recurrences 1
3. Chemotherapy may be considered only for recurrent tumors that cannot be resected and have already been irradiated 1

Critical Prognostic Factors

Several histologic features predict recurrence risk and should inform surveillance intensity:

• MIB-1 labeling index (proliferation marker) is more useful than histological features of anaplasia in predicting relapse 1, 4
• Recurrent tumors often show MIB-1 indices of 2.0-6.8%, prominent vascular proliferation, and remarkable synaptophysin expression 4
• High-grade features or extraventricular location confer less favorable prognosis 3

Common Pitfalls to Avoid

• Do not use chemotherapy as primary or adjuvant treatment - it is not indicated and lacks evidence 1, 2
• Do not routinely recommend radiotherapy or chemotherapy after complete resection - these tumors have low proliferation potential and favorable prognosis with surgery alone 2
• Do not delay surgical intervention in favor of systemic therapy - maximal safe resection provides the best outcomes 1, 3

Practical Recommendation

For newly diagnosed central neurocytoma, pursue maximal safe surgical resection without systemic chemotherapy. Reserve radiation for subtotal resection or recurrence. Consider temozolomide-based chemotherapy only as a last resort for recurrent disease that is unresectable and has already received radiation, recognizing that durable responses are not established 5, 1.