The Effect of Hippocampal Avoidance Whole Brain Radiotherapy on the Preservation of Long-Term Neurocognitive Function in Non-Small Cell Lung Cancer Patients With Brain Metastasis

Whole-brain radiotherapy (WBRT) is the mainstay of therapy in treating cancer patients with brain metastases, but unfortunately, it might also lead to decline in neurocognitive function. This study aims to investigate the preservation of long-term neurocognitive function in patients after hippocampal avoidance whole-brain radiotherapy (HA-WBRT). Retrospectively, 47 patients diagnosed with brain metastases of non-small cell lung cancer (NSCLC) between 2015-01-01 and 2017-12-31 at the Department of Oncology, XXX Hospital were selected and divided into 2 groups. Group A (n = 27) received HA-WBRT, whereas group B (n = 20) received WBRT. Neurocognitive function was analyzed at baseline and at 3, 6, 9, 12 and 24 months after radiotherapy, using Mine-Mental State Examination (MMSE) scales and Montreal Cognitive Assessment (MoCA) scales. The OS, PFS and tumor recurrence sites were also analyzed. When evaluated at 12 and 24 months after radiotherapy, the cognitive function scores of the hippocampal avoidance group were significantly higher than those of the non-hippocampal avoidance group (P < 0.001). In terms of patient survival, there was no significant difference in OS (P = 0.2) and PFS (P = 0.18) between these 2 groups. Fourteen patients in group A and 12 patients in group B had brain tumor recurrence after radiation, only one patient in group A occurred within 5 mm from the edge of the hippocampus (P > 0.05). In conclusion, HA-WBRT might have a protective effect on long-term neurocognitive function and did not affect patient survival.