New radiotherapy helps reduce cognitive damage in brain cancer

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Hippocampal-avoidance whole-brain radiotherapy plus memantine spared cognition in a phase III study.

When it comes to radiation therapy to treat brain cancer, hippocampal-avoidance whole-brain radiotherapy in conjunction with the drug memantine better preserved cognitive function and demonstrated similar cancer control outcomes compared with traditional whole-brain radiotherapy with memantine, researchers have found.

The brain cancer findings were presented by Mayo Clinic researchers at the 2018 annual meeting of the American Society for Radiation Oncology (ASTRO) in San Antonio, Texas.

Photo of Paul D. Brown, M.D.
Paul D. Brown, M.D.

"The hippocampus is a part of the brain associated with the limbic system and cognitive functions, including memory," said Paul D. Brown, M.D., a radiation oncologist at Mayo Clinic in Rochester, Minnesota, and senior author of the study. "Based on decades of translational studies, we know that even relatively modest doses of radiation to the hippocampi region of the brain contribute to cognitive problems for patients, such as memory loss."

Hippocampal-avoidance whole-brain radiotherapy was developed to help patients with brain cancer avoid cognitive damage during whole-brain radiation therapy, Dr. Brown said.

In the study, Dr. Brown and his colleagues compared hippocampal-avoidance whole-brain radiotherapy with traditional whole-brain radiotherapy with patients in both study arms taking memantine (Namenda).

Researchers enrolled 518 patients from July 2016 to March 2018. Patients were randomized to the two study arms. The median age of patients was 61.5 years. Treatment arms did not differ in baseline characteristics.

Researchers found that patients who received hippocampal-avoidance whole-brain radiotherapy had better preservation of cognitive function and achieved similar cancer control and overall survival than did patients who received standard whole-brain radiation therapy. The researchers also found that while age independently predicted for neurocognitive function, the neurocognitive benefit of hippocampal avoidance did not differ by age.

"The results of this trial could have a significant impact on patients," Dr. Brown said. "The incidence of metastatic brain cancer is estimated to be as high as 200,000 cases a year in the United States. And depending on a patient's primary cancer type, between 10 and 30 percent of patients with cancer will have cancer that spreads to the brain."

The study was one of only a few clinical trials in radiation oncology that originated in the laboratory, went on to a phase II trial and ultimately resulted in a phase III trial that demonstrated positive improvements, Dr. Brown said.


This article was originally published in Forefront, Mayo Clinic Cancer Center's online magazine, which ceased publication in December 2020.