For some brain cancer patients, pinpoint radiation of tumors, known as stereotactic radiosurgery, appears to do less damage to mental abilities than whole brain radiation, a new study finds.
Neither technique cures cancer that has spread to the brain, but both temporarily stop tumors from growing and equally extend survival, researchers said.
Stereotactic radiosurgery is nonsurgical radiation that precisely targets tumor areas. When just a few lesions exist, this directed type of radiation appears to provide a better quality of life by not altering short-term memory and thinking skills, the study found.
“We now have a better understanding of the toxicity of whole brain radiation, and we know that the toxicity of whole brain radiation is worse for patients than the recurrence of their cancer,” said lead researcher Dr. Paul Brown, from the department of radiation oncology at the Mayo Clinic in Rochester, Minn.
“With the results of this trial, we expect that practice will change and we will be reserving whole brain radiation for later in the patient’s disease course — for salvage treatment or end-stage palliative care,” he said.
Almost one-third of cancer patients develop metastatic lesions — cancer that has spread — in the brain, according to background notes with the study.
Whole brain radiation therapy is effective at shrinking visible metastases and keeping microscopic tumor deposits from being able to grow, said Dr. Jonathan Knisely, chief of the radiosurgery and stereotactic program at Northwell Health in New Hyde Park, N.Y.
Stereotactic radiosurgery, on the other, is “directed only at the visible metastases,” he explained.
“This study confirms that when choosing between the competing strategies the best choice is radiosurgery, the treatment that does not give any significant radiation dose to normal brain cells,” Knisely said.
However, the patients in this study had just one to three lesions, and the results might not apply to other cases, cancer specialists said.
For the study, Brown and colleagues randomly assigned 213 patients, average age 61, to stereotactic radiosurgery alone or stereotactic radiosurgery plus whole brain radiation.
The researchers tested patients’ mental abilities at the start of the study and again three months after treatment. They also looked at quality of life, functional independence, long-term mental status and overall survival.
At three months, Brown’s team found that patients treated with stereotactic radiosurgery alone had less mental decline than patients treated with stereotactic radiosurgery and whole brain radiation. Also, those treated with stereotactic radiosurgery alone had a better quality of life, Brown said.
Moreover, no significant difference in independence was seen at three months between the two patient groups.
In addition, average survival for those treated with pinpoint radiation was 10 months versus seven months for those in the combination treatment group.
Among patients who survived 12 months or longer, those treated with pinpoint radiation also had less mental decline than those who received both treatments, the researchers found.
The report was published July 26 in the Journal of the American Medical Association.
In the past, whole brain radiation was the only option, said Dr. Carey Anders, an assistant professor of medicine in the division of hematology and oncology at the University of North Carolina in Chapel Hill.
And even now, if a patient has many tumors or large tumors, whole brain radiation is still preferable, she said.
However, for a few small tumors, stereotactic radiosurgery may be the preferred choice “as long as a patient understands that their rate of progression may be higher without whole brain radiation, but it would not come at a cost of worse survival,” Anders said.
The decision comes down to the risks patients are willing to take at a very precarious time, said Anders, co-author of an accompanying journal editorial.
“I found some of my patients are very concerned about developing a new brain metastasis and would prefer to move forward with whole brain radiation therapy. I have other patients who are extremely concerned about the effect of whole brain radiation on their cognition and would prefer to avoid whole brain radiation therapy at all costs,” Anders said.
She welcomed the new results. “I think this study presents more solid guidance for patients concerned about cognitive function and allows them to make a decision that best meets their individual fears and needs,” she added.
For more on brain cancer, visit the American Cancer Society.