Background Derived neutrophil-lymphocyte ratio (dNLR) is a marker ofsystemic inflammatory response produced by proinflammatory cytokine activity oftumour microenvironment. dNLR is a simple, easily reproducible biomarker can be used to stratify the prognostic subgroups and decide the management in metastatic breast cancer.ThereissparsityofdataregardingderivedneutrophilratioinIndia.We evaluated dNLR as a prognostic biomarker in metastatic breast cancer patients treated at a North Indian tertiary cancer care centre. Methods We retrospectively reviewed the correlation between inflammatory biomarkers and clinical presentation and treatment outcome in 96 consecutively treated metastaticbreastcancerpatientsbetween2011-2014.Kaplan-Mereanalysisdone evaluate the impact on overall and progression-free survival. Results:Tabled 1Table: 121PParametersResultsDuration of presentation9 months(1-120)Metastatic sitebone: 59(60%), Lung:33(39%) liver: 22(22%)Receptor statusER+/PR+HER2- 43(44%), ER+/PR+HER2 +++:18(18%), ER-PR-HER2 +++: 15(15%), TNBC: 22(23%)Hemoglobin11.2 gm%(6.5-14.3)TLC6700/mm3 (3520-27200)ANC4412/mm3 (1090-11900)TreatmentChemotherapy 79(81%), Surgery 43 (44%)Response rateORR 53(54%), Complete remission 20(20%) Open table in a new tab Outofthe96patients,themedianagewas50years(range23-71years.Forty-five(46%) patientshadelevateddNLR.Withamedianfollow-upof19.4months,themedian Progression-freesurvival(PFS)andoverallsurvival(OS)was16.3monthsandnot reachedrespectively.2-yearestimatedPFSandOSwas38%and75%respectively. Baseline high dNLR was associated with significantly low objective response rate (ORR)(p=0.003),inferiorPFS(HR3.5,95%CI2.01-6.07,p-value<0.005)andreduced OS(HRof8.75,95%CI=2.5-29.9,P=0.001).Onmultivariateanalysis,other significant factors were associated with inferior PFS were elevated absolute neutrophil count(HR5.69,P0.003,95%CI1.7-18.3),responsetochemotherapy(HR0.22 P<0.005, CI 0.11-0.45). Conclusions In patients with metastatic breast cancer, inflammatory biomarker like elevated dNLR is strongly associated with low objective response rate, poor progression- freeandoverallsurvival. Inviewofeasyreproducibility,itcanbeincorporatedin management decisions as a prognostic factor across subgroups. Legal entity responsiblefor thestudy: AllIndiaInstituteofMedicalScience, New Delhi Funding:AllIndiaInstituteofMedicalScience,NewDelhi Disclosure All authors have declared no conflicts ofinterest.