Researchers have found that using a form of radiation therapy that targets individual tumors rather than whole-brain radiation is more optimal for patients with brain metastases, even if a larger number of tumors are present. These findings could help improve quality of life and cognitive function for this patient population. Results from the phase III randomized trial, which compared patient outcomes with each radiation modality, have been published by Aizer et al in JAMA.
“For patients with brain tumors, quality of life is so important. These results show that expanding the use of stereotactic radiation could minimize patients’ symptom burden and help preserve day-to-day functioning and cognitive abilities,” said lead author Ayal Aizer, MD, MHS, Director of Central Nervous System Radiation Oncology at Brigham and Women’s Hospital and Mass General Brigham Endowed Cancer Chair with Mass General Brigham Cancer Institute.
Previous studies have shown that, for patients with four or fewer brain metastases, stereotactic radiation—which uses focused beams of high-dose radiation to target individual tumors—improves cognitive function without jeopardizing long-term survival, when compared with whole-brain radiation. However, patients with larger numbers of brain tumors typically receive whole-brain radiation.
Recently, hippocampal-avoidance whole-brain radiation was shown to be better, from a cognitive standpoint, than whole-brain radiation without hippocampal-avoidance.
Current Study Methodology and Results
To compare stereotactic radiation with hippocampal-avoidance whole-brain radiation in patients with more than four brain metastases, researchers at Mass General Brigham Cancer Institute randomly assigned 196 patients across four treatment centers to receive either stereotactic radiation or hippocampal-avoidance whole brain radiation. Patients enrolled in the study had between 5 and 20 brain metastases.
Researchers used a scoring system to assess the severity of symptoms experienced by patients with brain tumors as well as assess how these symptoms interfered with the patients’ daily lives. In patients receiving stereotactic radiation, scores improved 6 months after radiation, while in those receiving hippocampal-avoidance whole-brain radiation, the scores worsened.
Patients managed with stereotactic radiation also displayed better performance status and could remain more independent with everyday activities than those who received hippocampal-avoidance whole-brain radiation. Most cognitive tests showed that patients who received stereotactic radiation performed better.
Median survival did not significantly differ between the two groups. New metastases were more common among those who received stereotactic radiation vs whole-brain radiation (45% vs 24% at 1 year); however, most new metastases were treated with repeated stereotactic radiation or did not require treatment. In addition, only 3.2% of patients had a recurrence in a tumor treated with stereotactic radiation therapy, compared with 39.5% in patients who received hippocampal-avoidance whole-brain radiation therapy.
Approximately 9% of patients in the stereotactic radiation group required subsequent whole-brain radiation to treat new brain tumors that later emerged. Stereotactic radiation often allowed patients to avoid whole-brain radiation, rather than merely delaying it.
The authors noted that limitations of the study include that it was not feasible to blind investigators regarding treatment assignment. In addition, high mortality rates among patients with multiple brain tumors could have impacted data analysis.
DISCLOSURE: This trial was supported by Varian, a Siemens Healthineers Company. Dr. Aizer reported research funding from Varian and NH TherAguix. For full disclosures of the study authors, visit jamanetwork.com.
