The prognosis for triple negative (TN) and hormone-refractory metastatic breast cancer (MBC) remains poor and treatment options are limited to cytotoxic agents. Furthermore, the optimal sequence of chemotherapy (CT) is unclear. In this prospective cohort study (E-SPEC), we observed optimal sequences of CT for improving long-term survival. This trial was registered with ClinicalTrials.gov (no. NCT02551263).
The study was conducted under a multi-institutional prospective observational design and involved patients with HER2-negative hormone-refractory MBC. Eligibility criteria were age 20-75 years; refractory to hormone therapy defined as TN type or recurrence during or within 6 months after the end of adjuvant treatment or refractory to at least one previous hormone therapy for MBC; and scheduled for first- and second-line CT after registration. All treatments were performed according to physician’s choice. Treatment regimens, efficacies and quality of life (QoL) were prospectively surveyed. Baseline data analysis included patient characteristics, real-world CT sequence of first- and second-line CT regimen and the reason for cessation of first-line CT.
Between June 2015 and July 2017, a total of 201 patients were enrolled, 194 of whom were analyzed. Mean age was 58.9 years; 142 patients (73.2%) had ER- and/or PgR-positive disease; 52 patients (26.8%) had TN. Most frequent regimen for first- or second-line CT was eribulin (ERI) (88.9%) among patients who received second-line CT. Frequent sequences were oral fluorouracil (FU) followed by ERI (18.3%), bevacizumab/paclitaxel (Bev/PTX) followed by ERI (13.5%), and ERI followed by Bev/PTX (11.1%). Patients who received taxanes as first-line CT had significantly more adverse event discontinuation than those with oral FU or ERI (p < 0.01).
In this real-world setting, ERI was administered in almost all first- or second-line regimens and taxane-based regimens were associated with more adverse event discontinuations. We intend to further investigate overall survival among CT sequences, as well as progression-free survival, new metastasis-free survival, type of progression and QoL.
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All authors have declared no conflicts of interest.