Expanding Indications for Stereotactic Radiosurgery in Brain Metastases

For years, the population of patients eligible for stereotactic radiosurgery (SRS) was defined largely by the design of the randomized trials that established the treatment's use, many of which permitted enrollment of patients with a limited number of brain metastases. Outside those trial boundaries, patients with a higher number of brain metastases were often directed toward whole brain radiation instead. Newer trial data have begun to challenge those historical boundaries, expanding the population of patients who may be appropriate candidates for SRS.

At the 2026 SNO ASCO CNS Metastases Conference in Boston, MA, Ayal Aizer, MD, MHS, highlighted recent advancements in stereotactic treatments for brain metastases. At the conference, Aizer, senior physician and director of central nervous system (CNS) radiation oncology at Dana-Farber Cancer Institute, and associate professor of Radiation Oncology at Harvard Medical School, spoke with CancerNetwork® about this presentation.

Aizer describes the biggest shift in the stereotactic management of brain metastases over the past several years: an expansion in the indications for SRS itself. Two specific developments that have driven this shift include new trial data supporting SRS for patients with a substantially higher number of brain tumors than was previously studied, and a trial establishing SRS as a safe and effective option in small cell lung cancer.

Transcript:

Aizer: Probably the biggest change we've seen in the stereotactic management of brain metastases over the past 2 to 3 years has been an expansion in the indications for its use. Previously, we had randomized trials that permitted patients with up to 4 brain metastases to enroll, and those trials generally randomized patients to [SRS] or whole brain radiation. Then, in the past year, we've had a trial that tells us SRS is a better treatment for up to 20 brain tumors, which is a big jump forward.

About a year ago, there was another trial that showed that in small cell lung cancer, SRS can be used for brain metastases. Previously, that specific primary tumor type was excluded from all prior SRS trials for a number of reasons, but this trial demonstrated that it's a safe, viable, and effective treatment. There are more patients who can get SRS now than have in the past, and that's probably been the single biggest change in the literature over the past couple of years.

Reference

Aizer A. Advances in the stereotactic management of brain metastases. Presented at the 2026 SNO ASCO CNS Metastases Conference; August 13-15; Boston, MA.