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Progress in rare central nervous system tumors
Marta Penas-Prado1, Terri S Armstrong, Mark R Gilbert
1Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
Purpose Of Review:
Although all primary central nervous system (CNS) tumors are rare, certain tumor types each represent less than 2% of the total and an annual incidence of about 1000 patients or less. Most of them are disproportionally diagnosed in children and young adults, but older adults can also be affected and are rarely recruited to clinical trials. Recent new molecular techniques have led to reclassification of some of these tumors and discovery of actionable molecular alterations.
Recent Findings:
We review recent progress in the molecular understanding and therapeutic options of selected rare CNS tumors, with a focus on select clinical trials (temozolomide and lapatinib for recurrent ependymoma; vemurafenib for BRAFV600E-mutated tumors), as well as tumor-agnostic approvals (pembrolizumab, larotrectinib) and their implications for rare CNS tumors.
Summary:
Although rare CNS tumors are a very small fraction of the total of cancers, they represent a formidable challenge. There is a need for dedicated clinical trials with strong correlative component in patients of all ages with rare CNS tumors. Critical research questions include relevance of the selected target for specific tumor types, persistence of the actionable biomarker at recurrence, blood-brain barrier penetration, and analysis of mechanisms of primary and acquired resistance.
Insights
Rare central nervous system (CNS) tumors present unique challenges, but recent molecular advances offer new therapeutic targets. Dedicated clinical trials are crucial for developing effective treatments for these uncommon cancers in all age groups.
Area of Science:
- Neuro-oncology
- Molecular Pathology
- Clinical Trial Design
Background:
- Primary central nervous system (CNS) tumors are rare, with specific types affecting fewer than 1000 patients annually.
- These rare CNS tumors disproportionately affect children and young adults, with limited clinical trial participation in older adults.
- Advances in molecular techniques are driving reclassification and identifying actionable molecular alterations in rare CNS tumors.
Purpose of the Study:
- To review recent progress in molecular understanding of rare CNS tumors.
- To discuss current and emerging therapeutic options, including clinical trials and tumor-agnostic approvals.
- To highlight the challenges and future research directions for rare CNS tumors.
Main Methods:
- Review of recent literature on molecular characterization of rare CNS tumors.
- Analysis of select clinical trials investigating targeted therapies (e.g., temozolomide, lapatinib, vemurafenib).
- Examination of tumor-agnostic drug approvals (e.g., pembrolizumab, larotrectinib) and their relevance.
Main Results:
- Progress in molecular understanding has identified actionable targets in rare CNS tumors.
- Specific clinical trials and tumor-agnostic therapies show promise for certain rare CNS tumor subtypes.
- Challenges remain in trial design, biomarker persistence, and understanding resistance mechanisms.
Conclusions:
- Rare CNS tumors require dedicated clinical trials with correlative science components for all age groups.
- Further research is needed to address target relevance, biomarker dynamics, blood-brain barrier penetration, and resistance mechanisms.
- Molecular insights are paving the way for more personalized therapeutic strategies in rare CNS oncology.
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