Hippocampal Brain Metastases Treatment With Whole Brain Radiotherapy or Stereotactic Radiosurgery: A First Single Center Experience

Hippocampal brain metastases are uncommon, and evidence regarding their management and outcomes remains limited. This study evaluated the efficacy and safety of whole-brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS) for hippocampal brain metastases at a single institution.

We retrospectively reviewed 21 patients treated for hippocampal brain metastases over a 20-year period. Clinical characteristics, treatment approaches, intracranial tumor control, treatment-related toxicity, and survival were analyzed. Eleven patients received WBRT and 10 received SRS.

The mean patient age was 60.7 years. Most patients were symptomatic (86%), had multiple brain metastases (71%), and had extracranial metastatic disease (76%). Memory impairment was documented in one patient. Among patients receiving WBRT, contralateral hippocampal avoidance was not feasible in five (45%) because of multiple brain metastases. The mean follow-up was 17.2 months. Intracranial tumor control was achieved in 18 patients (86%), and radionecrosis occurred in one patient (5%). The overall median survival was four months, and the estimated one-year survival rate was 42%. Intracranial tumor control rates were 91% after WBRT and 80% after SRS (p=0.49); the corresponding median survival times were one and five months, respectively (p=0.29). No acute or chronic treatment-related toxicity was documented, although post-treatment neurocognitive function was not systematically assessed.

WBRT and SRS provided high rates of intracranial tumor control with limited observed toxicity in this small cohort of patients with hippocampal brain metastases. However, overall survival remained poor. Larger studies incorporating standardized neurocognitive assessment are needed to clarify the comparative benefits and long-term safety of these treatment approaches.