Abstract P1-10-30: Survival benefit of eribulin for metastatic breast cancer depends on absolute lymphocyte count and neutrophil-lymphocyte ratio in peripheral blood

Abstract

Abstract Background and Aims: Eribulin is a cytotoxic anti-cancer agent targeting microtubule dynamics, which improves the prognosis of patients with metastatic breast cancer. Preclinical studies have shown that eribulin enhances anti-tumor immunity by inhibiting regulatory T cells and M2 macrophages. Along with advances of immunotherapy for breast cancer, there has been growing interest in such immunologic effects of eribulin. Here we investigated the association between the immunological status of peripheral blood and survival outcomes in patients receiving eribulin for metastatic breast cancer. Methods: Medical records of 125 patients who received eribulin for metastatic breast cancer at Hiroshima City Hiroshima Citizens Hospital between July 2011 and April 2019 were retrospectively reviewed. We collected the data on patients’ baseline characteristics, laboratory tests and clinical courses. Absolute lymphocyte count (ALC) and neutrophil-lymphocyte ratio (NLR) in peripheral blood at the start of treatment with eribulin were calculated, and their association with progression-free survival (PFS) and overall survival (OS) were analyzed with log-rank test. The cutoff values for ALC and NLR were determined based on their distribution in this cohort. Subgroup analyses by breast cancer subtypes were also conducted. Results: The mean age was 57 years (range, 28-88). Eighty (64%) and 14 (11.2%) patients were positive for hormone receptors and HER2 overexpression. One hundred and ten patients (88%) had received one or more lines of chemotherapy for metastatic disease. We divided the entire cohort into three groups, using the cutoff values of 1500 /µL for ALC and 5 for NLR. Accordingly, 30 patients (24%) had favorable immune status (i.e., ALC ≥1500 /µL), whereas immune systems were considered to be suppressed (i.e., NLR ≥5) in 19 patients (15.2%); the rest 76 patients (60.8%) had neutral immune status (i.e., ALC <1500 /µL and NLR <5). Overall, ALC ≥1500 /µL was significantly associated with better PFS (hazard ratio, 0.55; 95% CI, 0.35-0.88; p=.013). In contrast, NLR ≥5 were significantly associated with worse PFS (hazard ratio, 1.92; 95% CI, 1.11-3.32; p=.019) and OS (hazard ratio, 4.26; 95% CI, 2.29-7.91; p<.001). These trends in relationship between ALC/NLR and survival outcomes were consistent across subgroups. Conclusions: The potential role of immune status of peripheral blood, such as ALC ≥1500 /µL and NLR ≥5, in predicting the efficacy of eribulin for metastatic breast cancer was suggested. Selecting patients with favorable immune status will be important to make the best use of eribulin. Citation Format: Ayako Ueno, Shoichiro Ohtani, Kensuke Kawasaki, Mitsuya Ito, Takanori Kin, Reina Maeda. Survival benefit of eribulin for metastatic breast cancer depends on absolute lymphocyte count and neutrophil-lymphocyte ratio in peripheral blood [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-10-30.