Limited brain metastases: a narrative review

Area of Science:

• Neuro-oncology
• Radiation Oncology
• Medical Oncology

Background:

• Limited brain metastases are defined as an oligometastatic state suitable for focal therapy.
• The precise definition of "limited" brain metastases remains unclear.
• Exclusion of patients with untreated brain metastases from trials limits current understanding.

Purpose of the Study:

• To review the evolving definition and management of limited brain metastases.
• To discuss the role of stereotactic radiosurgery (SRS) in treating limited brain metastases.
• To explore the impact of systemic therapies and immunotherapy on SRS for brain metastases.

Main Methods:

• Narrative review of current literature on limited brain metastases.
• Analysis of randomized trials investigating metastasis-directed therapy and SRS.
• Discussion of emerging systemic therapies and their synergy with SRS.

Main Results:

• Stereotactic radiosurgery (SRS) offers an alternative to whole brain radiation therapy (WBRT), preserving neurocognitive function.
• SRS is effective for up to 4 brain metastases, with no detriment to overall survival.
• Emerging data suggests potential benefit from SRS for up to 10 brain metastases, with ongoing trials for higher numbers.

Conclusions:

• The definition of limited brain metastases is expanding based on recent clinical data.
• SRS is a viable and effective treatment for an increasing number of brain metastases.
• Advances in systemic therapies and immunotherapy may further broaden the application of SRS.