KRAS status and survival in multicenter study of RAS mutations (MURAS) in patients with colorectal liver metastases receiving Y90 radioembolization treatment.

Abstract

239 Background: Assessment of the clinical outcome and prognostic factors of patients receiving Y90 radioembolization to treat colorectal liver metastases. Methods: Multi-institution retrospective study of patients with CRLM who received Y-90 radioembolization after undergoing molecular testing was performed. Patients treated between 2008 and 2019 were included from 7 institutions within the United States and Europe. Patient demographics, systemic therapy regimens, tumor characteristics, laboratory values and overall survival were analyzed between patients with differing histopathologic and genomic status. Genomic profiling was obtained for KRAS, BRAF, PIK3CA, AKT, MEK, NRAS and MMR genes. Kaplan-Meier survival estimation and multivariate Cox regression were analyzed. Results: 445 patients treated with Y90 radioembolization fulfilled the inclusion criteria. Of the total cohort, 430 patients were available who had documented KRAS mutation status. Average age at diagnosis was found to be 58.4 years for all patients (57.6% male, 42.4% female). Decreased survival post Y90 treatment was shown in those patients with mutant KRAS. The median survival in patients with mutated KRAS was 5.7 months, as compared to 8.0 months in those patients with wild-type KRAS (p< 0.0001). Patient demographics including age, gender and race were not shown to be significant in overall survival post-Y90 treatment (p-values >0.05). The average number of systemic chemotherapy treatments prior to Y90 was 2.15 and was similar between KRAS groups (mutant vs wild type.) KRAS status persisted as a significant predictor of survival on multivariate analysis (p< 0.0001; HR 2.1 CI: 1.54-2.85). Conclusions: KRAS status is shown as a significant prognostic factor in patients with colorectal liver metastases receiving Y90 radioembolization.