A new approach to treating brain cancer is supported by insights into an unexpected source: taxi drivers in London.
Back in 2010, researchers discovered that a part of the brain called the hippocampus was larger in London taxi drivers than other adults who didn’t drive taxis. This part of the brain has been shown to be critical in new memory formation and learning. Researchers attributed the growth to the years of grueling training that taxi drivers endure to memorize some 25,000 streets and thousands of landmarks.
The study provided one example that adult brains were more versatile than previously thought. Other research had also supported the theory that neural stem cells located in the hippocampus play a major role in adult learning and memory.
Today, doctors are leveraging such research and insights from other studies to limit the side effects of treatment in patients with brain cancer. Nearly 200,000 people in the United States are diagnosed each year with tumors that form in the brain or cancer that spreads to the brain from elsewhere in the body.
To treat these tumors, doctors typically recommend partial-brain radiation or whole-brain radiation, which delivers radiation beams throughout the brain to kill visible tumors and potential cancer cells that might be too small to show up on a scan.
However, long-term side effects can range from bothersome to debilitating — affecting concentration, speech, motor skills and even a patient’s personality. Stem cells located in the hippocampus are some of the most sensitive in the brain to radiation, and researchers believe damage to these cells is responsible for many of these negative effects.
With hippocampal sparing, doctors can use advanced technology to shield the hippocampus from radiation beams, while still treating the rest of the brain. Crucial, but highly sensitive, stem cells in the hippocampus are protected, giving patients the best chance of limiting severe side effects such as memory loss, inattention and the inability to retain new information.
Current clinical trials show a significant potential benefit for patients, and more research is underway, says Dr. Siavash Jabbari, medical director of radiation oncology at the Laurel Amtower Cancer Institute and Neuro-Oncology Center at Sharp HealthCare.
“We do it for select patients in the right situations where we think it will help,” he says. “In our experience, it has been dramatic how these patients do, compared with the outcomes we’d expect otherwise.”
For the news media: To talk with Dr. Jabbari about the hippocampal sparing technique for an upcoming story, contact Erica Carlson, senior public relations specialist, at email@example.com.