S1263ESTRO 37Meanwhile, recurrent patients tended to exhibit increased post-RT peripheral neutrophil count (4.2×10 9 /L vs. 3.6×10 9 /L, p=0.09) and NLR (8.5 vs. 6.5, p=0.08) in comparison with non-recurrent patients.Multivariate analysis (MVA) identified patient age >50 years old (HR=3.4,p=0.02), weight loss during RT> 7.5% (HR=3.2,p=0.03), and post-RT peripheral NLR >7.05 (HR=2.5, p=0.04, 5-year OS 71.4% vs. 87.8%)as unfavorable prognostic factors for OS.There was also a nonsignificant trend in the MVA that patients with post-RT peripheral NLR >7.05 showed worse PFS (HR=1.9,p=0.06, 5-year PFS 64.1% vs. 81.8%). ConclusionPost-RT NLR predicted OS and PFS in LANPC patients treated with sequential chemoradiotherapy.The dynamic change of the routinely tested immune factors could help make appropriate treatment options and follow-up strategies.