Patients whose cancers have spread to the brain experience more learning and memory problems when radiation to their whole brain follows more targeted radiotherapy.
Study results presented at the 2008 American Society for Radiation Therapy and Oncology annual meeting in Boston found that whole brain radiation after radiosurgery doubled the risk of cognitive problems.
Stereotactic radiosurgery focused high amounts of radiation directly at brain tumors that had spread from primary cancer, including colorectal cancer. Whole brain radiation targeted wider areas in an attempt to destroy small, invisible metastases throughout the brain. Stereotactic radiosurgery is normally done in one high-dose treatment while whole brain radiation therapy delivers lower doses over several weeks.
Study patients were randomized to receive stereotactic radiosurgery alone or stereotactic radiosurgery followed by whole brain radiation. However, the study was stopped after initial results showed that patients who were getting whole brain radiation had a 49 percent decline in learning and memory four months after their treatment began. Patients who only had stereotactic radiosurgery had a 23 percent decline.
Learning and memory was measured by asking patients to remember a list of 12 words. For patients who had whole brain radiation, nearly half could not repeat 5 words.
Eric Chang, MD, from M.D. Anderson Cancer Center in Houston,who led the study and reported the results at ASTRO, said,
Results of this study show that initial stereotactic radiosurgery alone, coupled with close observation, could become the standard of care for patients newly diagnosed with brain metastases to best preserve their neurocognitive function.Results of this study could change the practice of how brain metastases are managed in the United States.
Find more information about stereotactic radiosurgery from RT Answers, a website for patients and families developed by ASTRO, the American Society for Therapeutic Radiology and Oncology. The site also has information about external beam radiation used for whole brain treatments.
SOURCE: Eric Chang MD, Phase III Randomized Clinical Trial of Radiosurgery with or without Whole Brain Irradiation in Patients Newly Diagnosed with 1 to 3 Brain Metastases, ASTRO abstract, presented September 22, 2008.