P-201 Retrospective evaluation of patients with colorectal cancer with metastasis in the central nervous system: Clinical and epidemiological prognostic factors

Abstract

prolonged survival in chemo-refractory patients with mCRC. Here, we investigated the role of NLR as a predictive biomarker in the CAVE mCRC trial.Methods: 77 patients enrolled in the CAVE mCRC trial, treated with cetuximab rechallenge plus avelumab, were included in the current analysis. Baseline NLR was calculated and, in line with previous findings, a cut-off value of 3 was used. Plasma samples of 67 out of 77 patients were available for analysis of circulating tumor DNA (ctDNA) mutations of KRAS, NRAS, BRAF and EGFR-S492R. Correlation of NLR<3 vs NLR 3 with median overall survival (mOS), median progression-free survival (mPFS) in the intention to treat (ITT) and ctDNA RAS/BRAF/EGFR wild-type (WT) population was performed.Results: In the ITT population, mOS was 11.6 months [95% Confidence Interval (CI), 8.4-14.8 months] and mPFS was 3.6 months (95% CI, 3.2-4.1 months). Patients with a baseline NLR < 3 (38/77, 49%) had a statistically significant improvement in mOS, 17.3 months (95% CI, 14.2-20.3), compared with patients with NLR 3 (39/77, 51%) that exhibited mOS of 8.9 months (CI 95% 6.4-11.4), (HR 0.44, CI 95% 0.25-0.76, P¼ 0.004). mPFS was 3.9 months (CI 95% 2.9-4.9) in patients with NLR < 3, compared to 3.5 months (CI 95% 2.3-4.6) in patients with NLR 3 (HR 0.71, CI 95% 0.44-1.13, P¼ 0.15). In the ctDNA WT population, mOS was not reached in the NLR < 3 group (23/ 48, 48%), whereas a mOS of 8.9 months (CI 95% 6.1-11.7), (HR 0.24, CI 95% 0.10-0.58, P¼ 0.001) was reported in patients (25/48, 52%) with NLR 3. A trend towards increased mPFS was observed in NLR < 3 population [5.2 months (CI 95% 2.9-7.6) vs 3.6 months (CI 95% 2.8-4.3) (HR 0.67, CI 95% 0.36-1.23, P¼ 0.19)]. Conclusions:In the CAVE mCRC study, baseline neutrophil to lymphocyte ratio < 3 was strongly correlated with improved survival and may represent a useful biomarker to predict response to retreatment with cetuximab plus avelumab.