Hippocampal sparing whole brain irradiation: Experience in our department

Abstract

Introduction Hippocampal neural stem-cell injury during whole-brain radiotherapy (WBRT) may play a role in memory decline. Hippocampal sparing whole brain radiotherapy (HS-WBRT) may delay or reduce the frequency and severity of neurocognitive decline in these patients. Purpose In this work we present initial data on the first 20 patients treated in our institution with HA-WBRT. Materials and Methods 20 patients have been treated in our institution with HS-WBRT, nine prophylactic cranial irradiation for small lung cancer and two for brain metastases, to a dose of 30 Gy (10-15 fractions). RTOG 0933 recommendations were applied for treatment planning. Magnetic resonance imaging (MRI) and computerized tomography (CT) sets were registered for each patient prior to delineation of the hippocampus. Intensity-modulated radiotherapy (IMRT) treatment plans for the Varian 2100CD linear accelerator were generated using the DMPO algorithm of Pinnacle TPS for optimizing a 12 beams solution class. Results The value of the maximum dose mean in the hippocampus was 15.63 Gy and the value of mean dose in the whole brain was 30.95 Gy, with a dose range of 36.4–40.2 Gy. The maximum dose to optic nerves and chiasma did not exceed 37.5 Gy. Mean number of segments and monitor units was 100 and 994 respectively. Conformation index mean value was 0.85. Conclusion The results obtained in this series of patients of our institution with HS-WBRT are comparable with the published series, fulfilling the recommendations of the RTOG 0933. Disclosure Authors disclose any relationship that may bias this work.