Abstract 302P
Background
Despite CDK4/6 inhibitors are the new standard of care in HR+/HER2-MBC, it was recognized not all patients (pts) benefit from the combination Palbociclib+Fulvestrant (P+F). Low lymphocyte-to-monocyte ratio (LMr), a marker of host inflammation, was associated with worse PFS in several tumor types, but have not been analysed extensively in breast cancer in the era of P+F. In this study we evaluated the utility of LMr for predicting PFS in HR+/HER2-MBC treated with P+F as first-line.
Methods
In this retrospective study, conducted in the UOC Territorial Oncology–Aprilia (ASL Latina, University of Rome “Sapienza”), we analyzed a consecutive cohort of 106 pts with HR+/HER2-MBC treated with P+F as first-line therapy between Dec2017 and Mar2020. Pre-treatment LMr was calculated by division of lymphocytes by monocytes measured in peripheral blood. ROC curves and AUC were used to determine the optimal cut-off value of LMr that was 5.2 (Youden Index). Using the univariate analysis of Cox Proportional hazard model and survival curves estimated using the method of Kaplan and Meier, we analyzed the correlation between LMr and PFS.
Results
The pts’median age was 59 years [30–81]. The median LMr level was 5.81 [1.2-20]: in 54% (57 pts) we observed a LMr <5,2 and in 46% (49 pts) a LMr >5,2. Lower LMr was associated with worse outcome (p<0.001). After a median follow up of 18 months [1-NA], pts with LMr <5,2 had a median PFS of 3 months [1-6 months, 95% CI 0.8-3.6], contrary to pts with LMr>5.2 whose PFS has not yet been reached. Inclusion of LMr in multivariable models significantly improved prediction of PFS in this subset of pts.
Conclusions
Despite the study’s limitations, our results suggest the utility of LMr analisys before starting P+F treatment to predict who will take advantage from this combination of drugs. It may lead to personalize management in HR+/HER2-MBC decreasing wastes of resources for the National Health System ensuring the best pts’ quality of life.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
ASL Latina-University of Rome “Sapienza”.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.