Radiation Therapy for Brain Metastases

Publication Date: May 6, 2022

Indications for SRS alone for intact brain metastases

For patients with an ECOG performance status of 0-2 and up to 4 intact brain metastases, SRS is recommended. (Strong, High)
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For patients with an ECOG performance status of 0-2 and 5-10 intact brain metastases, SRS is conditionally recommended. (Conditional (weak), Low)
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For patients with intact brain metastases measuring <2 cm in diameter, single-fraction SRS with a dose of 2000-2400 cGy is recommended. (Strong, Moderate)
Implementation remark: If multifraction SRS were chosen (eg, V12 Gy >10 cm3 [see KQ4]), options include 2700 cGy in 3 fractions or 3000 cGy in 5 fractions.
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For patients with intact brain metastases measuring ≥2 to <3 cm in diameter, single-fraction SRS using 1800 cGy or multifraction SRS (eg, 2700 cGy in 3 fractions or 3000 cGy in 5 fractions) is conditionally recommended (see KQ4). (Conditional (weak), Low)
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For patients with intact brain metastases measuring ≥3 to 4 cm in diameter, multifraction SRS (eg, 2700 cGy in 3 fractions or 3000 cGy in 5 fractions) is conditionally recommended. (Conditional (weak), Low)
Implementation remarks:
If single-fraction SRS were chosen, doses up to 1500 cGy may be used (see KQ4).
Multidisciplinary discussion with neurosurgery to consider surgical resection is suggested for all tumors causing mass effect, irrespective of tumor size.
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For patients with intact brain metastases measuring >4 cm in diameter, surgery is conditionally recommended, and if not feasible, multifraction SRS is preferred over single-fraction SRS. (Conditional (weak), Low)
Implementation remark: Given limited evidence, SRS for tumor size >6 cm is discouraged.
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For patients with symptomatic brain metastases who are candidates for local therapy and CNS-active systemic therapy, upfront local therapy is recommended. (Strong, Low)
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For patients with asymptomatic brain metastases eligible for CNS-active systemic therapy, multidisciplinary and patient-centered decision making is conditionally recommended to determine whether local therapy may be safely deferred. (Conditional (weak), Expert Opinion)
Implementation remark: The decision to defer local therapy should consider factors such as brain metastasis size, parenchymal brain location, number of metastases, likelihood of response to specific systemic therapy, access to close neuro-oncologic surveillance, and availability of salvage therapies.
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Indications for observation, postoperative SRS, WBRT, or preoperative SRS

For patients with resected brain metastases, radiation therapy (SRS or WBRT) is recommended to improve intracranial disease control. (Strong, High)
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For patients with resected brain metastases and limited additional brain metastases, SRS is recommended over WBRT to preserve neurocognitive function and patient-reported QoL. (Strong, Moderate)
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For patients whose brain metastasis is planned for resection, preoperative SRS is conditionally recommended as a potential alternative to postoperative SRS. (Conditional (weak), Low)
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Indications for WBRT for intact brain metastases

For patients with favorable prognosis (estimated using a validated brain metastasis prognostic index) and brain metastases ineligible for surgery and/or SRS, WBRT (eg, 3000 cGy in 10 fractions) is recommended as primary treatment. (See KQ1, recommendations 7 and 8 for consideration of systemic therapy.) (Strong, High)
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For patients with favorable prognosis and brain metastases receiving WBRT, hippocampal avoidance is recommended. (Strong, High)
Implementation remark: Hippocampal avoidance is not appropriate in cases of brain metastases in close proximity to the hippocampi or in cases of leptomeningeal disease.
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For patients with favorable prognosis and brain metastases receiving WBRT or hippocampal avoidance WBRT, addition of memantine is recommended. (Strong, Low)
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For patients with favorable prognosis and limited brain metastases, routine adjuvant WBRT added to SRS is not recommended. (Strong, High)
Implementation remark: To maximize intracranial control and/or when close imaging surveillance with additional salvage therapy is not feasible, adjuvant WBRT may be offered in addition to SRS.
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For patients with poor prognosis and brain metastases, early introduction of palliative care for symptom management and caregiver support are recommended. (Strong, Moderate)
Implementation remarks:
Supportive care only (with omission of WBRT) should be considered.
If WBRT is used, brief schedules (eg, 5 fractions) are preferred.
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Risks of symptomatic radionecrosis with WBRT and/or SRS

For patients with brain metastases, limiting the single-fraction V12Gy to brain tissue (normal brain plus target volumes) to ≤10 cm3 is conditionally recommended. (Conditional (weak), Low)
Implementation remark: Any brain metastasis with an associated tissue V12Gy >10 cm3 may be considered for fractionated SRS to reduce risk of radionecrosis (see KQ1).
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Table

Table 5. Recommended postoperative cavity single-fraction SRS dosing guidance

Cavity volume (cm3) Single-fraction SRS dose (cGy)
<4.2 cm3 2000 cGy
≥4.2 to <8.0 cm3 1800 cGy
≥8.0 to <14.4 cm3 1700 cGy
≥14.4 to <20.0 cm3 1500 cGy
≥20.0 to <30.0 cm3 1400 cGy
≥30.0 cm3 to <5.0 cm max 1200 cGy
Given the irregular shape of surgical cavities, the total prescribed dose should be based on the surgical cavity volume with a maximum cross-sectional diameter of <5.0 cm.

Recommendation Grading

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Overview

Title

Radiation Therapy for Brain Metastases

Authoring Organization

Publication Month/Year

May 6, 2022

Document Type

Guideline

Country of Publication

US

Document Objectives

This guideline provides updated evidence-based recommendations addressing recent developments in the management of patients with brain metastases, including advanced radiation therapy techniques such as stereotactic radiosurgery (SRS) and hippocampal avoidance whole brain radiation therapy and the emergence of systemic therapies with central nervous system activity.

Target Patient Population

Adults with brain metastases

Target Provider Population

Radiation oncologists, neuroradiologists, oncologists and allied providers caring for adults with brain metastases

Inclusion Criteria

Male, Female, Adult, Older adult

Health Care Settings

Hospital, Outpatient, Radiology services

Intended Users

Radiology technologist, nurse, nurse practitioner, physician, physician assistant

Scope

Treatment, Management

Diseases/Conditions (MeSH)

D018787 - Radiation Oncology, D001932 - Brain Neoplasms

Keywords

radiation therapy, Brain Metastases, brain cancer

Source Citation

Gondi V, Bauman G, Bradfield L, Burri SH, Cabrera AR, Cunningham DA, Eaton BR, Hattangadi-Gluth JA, Kim MM, Kotecha R, Kraemer L, Li J, Nagpal S, Rusthoven CG, Suh JH, Tomé WA, Wang TJC, Zimmer AS, Ziu M, Brown PD. Radiation Therapy for Brain Metastases: An ASTRO Clinical Practice Guideline. Pract Radiat Oncol. 2022 May 6:S1879-8500(22)00054-6. doi: 10.1016/j.prro.2022.02.003. Epub ahead of print. PMID: 35534352.