Abstract 341P
Background
Previous studies evaluating the impact of race on survival in triple-negative breast cancer (TNBC) have come to inconsistent conclusions. In this study we further explore relative survival by race within a TNBC population receiving care in the controlled settings of clinical trials.
Methods
Phase II and III open-label breast cancer studies having completed their primary analysis were selected from the Medidata Enterprise Data Store comprised of 19,000+ historical clinical trials, for de-identified aggregate analyses. The Synthetic Control Database (SCD) for this study contains 1215 patients with metastatic TNBC enrolled in trials between 2010 and 2017. Patients were stratified by race. Overall survival (OS), progression-free survival (PFS) and duration of response (DOR) were assessed using a Kaplan-Meier analysis. Baseline covariates were compared using Wilcoxon and Chi-Square tests. We assessed the potential impact of additional factors on survival including age, body mass index (BMI), baseline leukocytes, dose adjustments and adverse events.
Results
The racial breakdown of the SCD population was 12% Black and 88% Non-Black (NB). Black study participants had a higher BMI than NB patients (median 30.3 vs. 25.8, p<0.001) and were slightly older at time of enrollment (54 vs. 51 years of age, p=0.11). The proportion of patients experiencing a complete or partial remission were similar between groups (34% Black vs. 33% NB), however, the unadjusted OS, PFS and DOR were consistently shorter (but not statistically different) in Black patients: median OS of 349 v. 362 days (hazard ratio 0.91, 95% CI: 0.74, 1.11), PFS of 128 vs. 140 days (HR 0.93, CI: 0.78, 1.12) and DOR of 140 days vs. 172 days (HR 0.82, CI: 0.59, 1.13). Although not statistically significant, Black patients had lower leukocyte levels upon study entry than NBs (median 5.6 vs. 6.0 x 109/L) and also experienced more dose modifications (p=0.05).
Conclusions
Compared to their NB counterparts, Black patients with TNBC demonstrated a slightly shorter OS, PFS and DOR that lacked statistical significance. This analysis also suggests that Black patients experience more dose modifications on study. These findings are intriguing and suggest that further investigation of possible racial disparity in TNBC outcomes is required.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.