Memory Avoidance Whole Brain Radiotherapy vs Hippocampal Avoidance Whole Brain Radiotherapy (Athena 2 Trial)

Brain metastases happen when cancer spreads from its original location to the brain. For people with brain metastases, whole brain radiotherapy (WBRT) is important in reducing neurologic symptoms and maximizing intracranial control. Previous studies have shown that adding a drug called memantine to WBRT can help lower the risk of cognitive decline. Previous studies have also shown that hippocampal avoidance WBRT (HA-WBRT) with memantine can reduce the risk of cognitive decline even more. This combination is considered a standard of care option for people with brain metastases. Even though HA-WBRT successfully reduces the risk of cognitive decline for people with brain metastases, many people still experience some cognitive decline. This means that new treatments are needed to better protect brain function for this population. While avoiding the hippocampus is helpful, there are still many other parts of the brain that may be affected by radiation. Important cognitive structures such as the amygdala, corpus callosum, and fornix are involved with memory processing, executive function, complex task performance, memory formation, and recall. Avoiding these cognitive structures can further preserve cognition for people receiving WBRT. This study investigates the avoidance of additional cognitive structures (the amygdala, corpus callosum, fornix, hypothalamus, and pituitary) with memory avoidance whole brain radiotherapy (MA-WBRT). The safety and feasibility of MA-WBRT has already been demonstrated. The purpose of this study is to compare MA-WBRT with memantine to HA-WBRT with memantine, which is currently the standard of care for people with extensive brain metastases.