Predictors of Discontinuation of Eribulin Therapy for Metastatic Breast Cancer: A Retrospective Cohort Study

This study aimed to identify clinical predictors associated with early discontinuation of eribulin therapy in patients with unresectable or recurrent breast cancer.

We retrospectively reviewed data for 63 patients with breast cancer starting eribulin therapy between August 2011 and December 2022 at a single institution. Patients with missing data for hormone receptor/human epidermal growth factor receptor 2 (HER2) status or baseline hematological parameters were excluded. Data were collected on demographics, tumor subtype, comorbidities, concomitant medications, and baseline complete blood count. The primary outcome was time to treatment discontinuation for any reason. Cox proportional hazards models were used to identify predictors of discontinuation, stratified by reason: progressive disease (PD) or adverse events (AE).

The median age was 62 years; 69.8% were hormone receptor-positive and 15.9% HER2-positive. During follow-up, 61 out of 63 patients (96.8%) discontinued treatment. Discontinuation was due to PD in 69.8%, AE in 17.5%, and other causes in 9.5%. Considering all reasons, multivariate analysis identified a neutrophil-to-lymphocyte ratio (NLR) ≥3.5 [hazard ratio (HR)=1.97, p=0.020] as an independent predictor of discontinuation. Multivariate analysis identified dyslipidemia (HR=3.59, p=0.009) as independent predictors of PD-related discontinuation, whilst antidepressant use (HR=0.22, p=0.049) was associated with a lower risk of discontinuation. Univariate analysis showed that oral glucocorticoid use was associated with a higher risk of AE-related discontinuation (HR=4.79, p=0.013).

High NLR and dyslipidemia were associated with early discontinuation of eribulin therapy. These findings highlight the need for individualized treatment strategies based on baseline risk factors.