A study presented at this year’s American Society of Clinical Oncology conference found that, contrary to prior belief, attacking tumors by radiating the whole brain harms patients’ thinking, memory and speech, and does not improve their survival.
“Our study shows that the negative effects of whole-brain radiation far outweigh the positive,” says study author Paul Brown, M.D., professor of Radiation Oncology at MD Anderson.
Conventionally, cancer that spreads to the brain is treated with radiosurgery — ultra-focused beams of radiation aimed at the tumor with millimeter precision, followed by whole-brain radiation to reduce the likelihood of future tumors cropping up.
Radiosurgery usually involves a one-time-only, highly focused treatment with a tool such as a Gamma Knife. Whole-brain radiation therapy, on the other hand, exposes the entire brain to 20-minute doses of less-intense radiation once a day for 10 to 15 days.
At MD Anderson, Brown led a study of 213 patients with one to three brain tumors to determine whether the risks of whole-brain radiation are worth its benefits for controlling cancer. Half the patients had radiosurgery only, while the other half had radiosurgery followed by whole-brain radiation.
Three months later, almost all — 92% — of patients who received both treatments had cognitive decline, versus 64% of those who had radiosurgery only.
Patients who underwent whole-brain radiation also experienced significant declines in their quality of life compared with radiosurgery patients. Hair loss, skin redness, dry mouth, fatigue and thinking problems are typical side effects of whole-brain radiation, Brown says. Radiosurgery’s side effects are minimal.
“Our study confirms that giving less treatment offers the best results for our patients with brain tumors that have spread from other locations,” Brown says.
An estimated 400,000 patients in the U.S. each year have cancer that spreads to the brain, usually from the lungs, breasts or other sites. Brown predicts that, based on this study, doctors likely will begin recommending radiosurgery alone for many of these patients, combined with close monitoring. If patients develop new tumors, targeted radiation will zap the tumors as they occur, without ever resorting to whole-brain radiation.
“Whole-brain radiation will be reserved for patients whose cancer is more advanced,” he says.