New Clinical Trials Find Fractionated Brain Radiation Significantly Extends Patient Survival

Two studies presented at the ASTRO Annual Meeting reported encouraging results for focused radiation treatment of brain metastases. In a randomized phase 3 trial involving large, surgically removed metastases, fractionated stereotactic radiosurgery delivered over three to five sessions reduced cancer recurrence at the surgical site and was associated with nine months longer median survival than single-session treatment, with similar side effects. Researchers said the findings provide strong support for considering fractionated treatment as a standard postoperative option for larger metastases. A separate trial in patients with small cell lung cancer that had spread to the brain found median survival of 17 months after focused stereotactic radiosurgery, compared with nine months after whole-brain radiation; however, radiosurgery did not improve the trial’s primary measure of time to cognitive decline, and neurological deaths and serious treatment-related effects did not significantly differ.
Small cell lung cancer has historically been an exception to the shift toward focused radiosurgery because clinicians worried that treating only visible brain tumors could leave microscopic disease untreated elsewhere in the brain. The trial was the first randomized phase 3 comparison of radiosurgery and whole-brain radiation in this population; its investigator said the results support more individualized discussions about which approach is right for each patient.
The large-metastasis trial enrolled 242 patients with one to four brain metastases, all of whom had surgery to remove a lesion at least 2 cm in size. The treatment schedules were 12–20 Gy in one session or, for fractionated treatment, 27 Gy in three sessions for smaller cavities and 30 Gy in five sessions for cavities at least 30 cc.
The rationale for splitting radiation across sessions is to let healthy tissue recover between doses while still delivering an effective dose to the treatment area, principal investigator Paul Brown explained.
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