CNS radiation therapy: Primary brain tumors, brain metastases, SRS, and post-op SBRT Book Section
| Authors: | Zinovoy, M. R.; Beal, K.; Barsky, A. R.; Yu, Y.; Pike, L. R. G. |
| Editors: | Cuaron, J. J.; Braunstein, L. Z. |
| Article/Chapter Title: | CNS radiation therapy: Primary brain tumors, brain metastases, SRS, and post-op SBRT |
| Abstract: | Radiation therapy (RT) is an integral treatment modality in the management of primary and secondary brain tumors, significantly improving intracranial control, overall survival, and symptom palliation. Appropriate planning and execution of radiation is vital in the multidisciplinary management of primary brain tumors such as gliomas, meningiomas, and brain metastases. Glioblastoma is the most commonly diagnosed malignant primary brain tumor, and RT is a core component of up front and salvage management. Meningioma constitutes the most common primary brain tumor overall, and radiation is used both definitively and adjuvantly in the treatment of low, intermediate, and high-risk meningiomas. Low-grade gliomas (LGG) and high-grade gliomas (HGG) comprise a smaller proportion of primary brain tumors. The timing, volume, modality, and dose of RT in the management of LGG are ongoing topics of controversy. Brain metastases are ten-fold more common than primary brain tumors and thus represent most intracranial tumors treated with RT. Historically, the mainstay of RT-based treatment was whole-brain radiotherapy (WBRT). Although WBRT can yield durable intracranial control, it can result in significant and long-term neurotoxicity. Thus, for the treatment of limited (up to 15) brain metastases, stereotactic radiosurgery (SRS) has emerged as the preferred treatment. SRS is more effective in terms of lesion-level local control, is not associated with long-term neurocognitive effects, and can be delivered in one to five days. With the development of Central Nervous System (CNS)-active systemic therapeutics and improved prognosis for patients with brain metastases, treatment decisions in this patient population have become increasingly complex. We advocate for a multidisciplinary, multimodal, and patient-centered approach that balances the potentially competing goals of disease control and treatment toxicity. Leptomeningeal carcinomatosis or leptomeningeal disease (LMD) is a frequently morbid and lethal manifestation of intracranial metastases, with seeding of the cerebrospinal fluid space through hematogenous spread or direct contact of brain metastases with the leptomeninges. Over the last decade, our understanding of this disease entity has improved significantly. The diagnosis of leptomeningeal disease is based on the combination of history and clinical examination, imaging, and cerebrospinal fluid (CSF)_cytology. In isolation, each component has limited sensitivity and negative imaging, or CSF cytology does not exclude the diagnosis. Use of CSF circulating tumor cells (CTCs) has significantly improved both sensitivity and specificity of diagnostic testing. Additionally, leptomeningeal disease should be distinguished from nodular meningeal disease or pachymeningeal disease, which is an iatrogenic seeding of the dura but not the pia or arachnoid mater. The historical standard of care for patients with leptomeningeal disease is WBRT and involved-field irradiation of symptomatic spinal disease. However, recent work led by Memorial Sloan Kettering Cancer Center (MSKCC) investigators has demonstrated a potential disease control and overall survival benefit to the use of more comprehensive RT in the form of proton craniospinal radiation (pCSI). Furthermore, recent trials in patients with oncogene-driven Non-Small Cell Lung Cancer and HER2-positive have demonstrated robust and sometimes durable responses of LMD to targeted therapies such as osimertinib and trastuzumab deruxtecan. When combined with the aggressive nature of this disease, urgent evaluation and intervention with multi-modal therapy with close monitoring is emerging as the approach of choice. Controversies remain around the selection and optimal sequencing of drug or radiation therapy. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2025. |
| Keywords: | chemotherapy; neurosurgery; radiotherapy; glioblastoma; brain metastasis; stereotactic radiosurgery; arthroplasty; risk management; brain metastases; low-grade gliomas; whole brain radiotherapy; radiation damage; proton therapy; leptomeningeal disease; high-grade glioma; low-grade glioma; glioblastomas; high-grade gliomas; electrotherapeutics; primary brain tumors; whole-brain radiation; proton beam therapy; medicaments |
| Book Title: | Radiation Oncology Clinical Fundamentals |
| ISBN: | 978-3-031-77558-1 |
| Publisher: | Springer Nature |
| Date Published: | 2025-01-01 |
| Start Page: | 1 |
| End Page: | 13 |
| Language: | English |
| DOI: | 10.1007/978-3-031-77559-8_1 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Book chapter: 1 -- Source: Scopus |
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