Stereotactic radiosurgery is a standard of care but not the standard of care. Stereotactic radiosurgery is a reasonable approach for smaller tumors and smaller surgical cavities, and whole-brain radiotherapy is also a reasonable choice for larger cavities.— Vinai Gondi, MD
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Formal discussant of both trials, Vinai Gondi, MD, Director of CNS Radiation Oncology at Northwestern Medicine Cancer Center in Warrenville, Illinois, offered a somewhat more nuanced take on the data from these studies.
To begin, he commended the authors of both studies. “These were both well-designed randomized trials. One was conducted at a leading brain tumor center, the MD Anderson Cancer Center, and the other was a National Cancer Institute–sponsored clinical trial more reflective of radiosurgical and neurosurgical practice in our community.”
Dr. Gondi said that patients with resected brain metastases have three options: observation, stereotactic radiosurgery, and whole-brain radiotherapy. All three approaches have pluses and minuses.
Pros and Cons of Options
“These trials tell us about the upsides and downsides of these approaches. Observation is associated with increased relapse, and the only low-risk cohort that was identified was those with preoperative tumor size smaller than 2.5 cm. Stereotactic radiosurgery improves control of the surgical bed relative to observation, and relative to whole-brain radiotherapy, stereotactic radiosurgery had less of a deleterious effect on cognition,” continued Dr. Gondi.
“However, whole-brain radiotherapy compared with stereotactic radiosurgery improves intracranial control and better prevents the harder-to-salvage relapses in the surgical bed. Whole-brain radiotherapy also has modest cognitive effects.”
No One Standard of Care
Dr. Gondi recommended that when talking to patients, these options should be presented with an appropriate balance. “Whole-brain radiotherapy had an increase of 17.5% in modest cognitive effects at 6 months compared with stereotactic radiosurgery but also achieved a 23% improvement of control in the surgical bed, where relapses after stereotactic radiosurgery can be challenging to treat,” he continued.
“These data give us the opportunity to have discussions with patients, taking into account their tumor size, performance status, and what matters most to them: tumor control or cognition. There is no one standard of care. Stereotactic radiosurgery is a standard of care but not the standard of care. Stereotactic radiosurgery is a reasonable approach for smaller tumors and smaller surgical cavities, and whole-brain radiotherapy is also a reasonable choice for larger cavities,” Dr. Gondi indicated.
As neither modality improves survival, Dr. Gondi suggested that future directions should focus on improving outcomes in patients. “One area of study is preoperative stereotactic radiosurgery in patients at risk for leptomeningeal dissemination at surgery,” he shared. “Ongoing studies are also examining whether whole-brain radiotherapy can be delivered more safely using cognitive-preservation strategies of prophylactic memantine and hippocampal avoidance.” ■
Disclosure: Dr. Gondi reported no potential conflicts of interest.
Two separate randomized trials presented at the 58th Annual Meeting of the American Society of Radiation Oncology (ASTRO) affirmed the value of stereotactic radiosurgery as an option for postoperative treatment of the surgical cavity of resected brain metastases, potentially avoiding the cognitive...