NRG Oncology CC001: A phase III trial of hippocampal avoidance (HA) in addition to whole-brain radiotherapy (WBRT) plus memantine to preserve neurocognitive function (NCF) in patients with brain metastases (BM).

Abstract

2009 Background: NRG CC001, a phase III trial of WBRT plus memantine (WBRT+M) with or without HA, sought to evaluate the neuro-protective effects of lowering the hippocampal radiation dose. Methods: Patients (pts) with BM were stratified by RPA class and prior radiosurgery/surgery and randomized to WBRT+M or HA-WBRT+M (30Gy/10 fractions). Standardized NCF tests were performed at baseline, 2, 4, 6, and 12 months (mos). The primary endpoint was NCF failure, defined as decline using the reliable change index on Hopkins Verbal Learning Test-Revised, Trail Making Test, or Controlled Oral Word Association. Cumulative incidence estimated NCF failure (death without NCF failure was competing risk); between-arms differences tested using Gray’s test. Deterioration at each collection time point was tested using a chi-square test. Patient-reported symptoms were assessed using the MD Anderson Symptom Inventory Brain Tumor module and analyzed using mixed effects models and t-tests. Results: From 7/2016 to 3/2018, 518 pts were randomized. Median follow-up was 7.9 mos. HA-WBRT+M was associated with lower NCF failure risk (adjusted hazard ratio (HR) = 0.74, p = 0.02) due to lower risk of deterioration in executive function at 4 mos (p = 0.01) and encoding (p = 0.049) and consolidation (p = 0.02) at 6 mos. Age≤61 predicted lower NCF failure risk (HR = 0.60, p = 0.0002); non-significant test for interaction indicated independent effects of HA and age. Patient-reported fatigue (p = 0.036), difficulty speaking (p = 0.049) and problems remembering things (p = 0.013) at 6 mos favored the HA-WBRT+M arm. Imputation models accounting for missing data also favored the HA-WBRT+M arm for patient-reported cognition (p = 0.011) and symptom interference (p = 0.008) at 6 mos. Treatment arms did not differ in toxicity, overall survival, or intracranial progression. Conclusions: HA during WBRT+M for BM better preserves NCF and patient-reported symptoms, while achieving similar intracranial control and survival. Supported by grants UG1CA189867 (NCORP), U10CA180868 (NRG Oncology Operations), DCP from the National Cancer Institute. Clinical trial information: NCT02360215.