A single institution real-world disease free survival analysis of adjuvant capecitabine in TNBC patients with residual disease following neoadjuvant chemotherapy.

Abstract

e12502 Background: Adjuvant capecitabine (Cape) is standard of care for triple negative breast cancer (TNBC) cancer patients with residual disease following neoadjuvant chemotherapy. This is based on data from the CREATE-X study, which demonstrated an increase in disease-free survival (DFS) and overall survival in the intent-to-treat population, but this effect was most pronounced in the TNBC population. However, the generalizability of the study has been questioned due to previously negative studies, the homogenous nature of study participants, and the lack of differentiation for HER2 positive patients. We proposed a real-world DFS analysis of the efficacy of adjuvant Cape in TNBC patients (pts) with residual cancer burden (RCB) I though III versus a matched control group. Methods: This is a retrospective analysis to assess the DFS in a real world setting (primary endpoint) of patients with histologically confirmed TNBC with RCB-I through III post-surgery, who received neoadjuvant chemotherapy with anthracycline and/or taxane and adjuvant Cape. Secondary endpoints included: frequency of dose reductions, frequency of discontinuation, physician preferred dosing and adverse drug events. Survival curves were estimated via Kaplan-Meier method and hazard ratios with 95% confidence intervals determined using Cox proportional-hazards model. Results: A total of 401 pts were screened for TNBC with 101 pts meeting the inclusion criteria for study: 47 and 54 in the control group and capecitabine group, respectively. Demographics consisted of 38% Caucasian women and 62% African American women. In the control group, 12 pts (12.5%) experienced disease recurrence: nine at 12 months and three at 24 months. Three (6.4%) had local regional recurrence. In the Cape group, eight pts (14.8%) had disease recurrence: two at 12 months and six at 24 months. Six (11.1%) had a local regional recurrence. In Kaplan-Meier survival analysis, the control group had 72.9% DFS at 24 months, while the Cape group had 69.8% DFS at 24 months (p = 0.77). Twenty-nine patients had RCB-III: 11 in the control group and 18 in the Cape group. In subgroup analysis of the RCB III group, the control had 36.4% DFS at 24 months, while the Cape group had 88.9% DFS (p = 0.007). The preferred dosing was 1250 mg/m2 with 12 pts (22%) and 19 pts (35%) requiring dose reduction or discontinuation, respectively. Adverse events were reported in 46 pts (85%). Conclusions: In this single institution real-world data, adjuvant Cape does not appear to offer any additional survival benefit to triple negative patients with residual disease following neoadjuvant chemotherapy. However, this study showed an increase in DFS for RCB III when compared to the control group. Given the limited patient numbers, a larger sample size will be required to determine the validity of benefit seen in the patients with RCB class III.