Cancer recurrence and survival in patients with early-stage triple-negative breast cancer in a U.S. local oncology practice.

Abstract

6114 Background: Breast cancer (BC) patients with triple negative (TN) status, defined as negative expression for estrogen, progesterone, and HER2 receptors, carry a poor prognosis. The objective of this study was to evaluate, in a real world context, the impact of TN status on disease recurrence and survival among early-stage BC patients treated with adjuvant chemotherapy (CT). Methods: The Georgia Cancer Specialist Database (2003-2004) was used. Patients with early stage (I-III) BC, confirmed TN/non-TN status, and treated with adjuvant CT were followed from initial BC diagnosis to the earliest of death, BC recurrence, or loss to follow-up. The primary outcome was disease free survival (DFS, defined as the time in which a patient is alive without recurrence). The secondary outcome was recurrence. Patients were stratified into TN and non-TN groups. Kaplan-Meier curves were used to compare the event rates between two groups. The impact of TN status on DFS and recurrence was further examined with multivariate Cox models, adjusting for age, comorbidity, body mass index, smoking status, BC stage, surgical, and radiological therapies. Results: The study sample included 1,572 patients, with 26.3% (n = 414) being TN. The mean age at BC diagnosis was 52, and 88% were diagnosed under 65. The proportion of patients with stage I, II, and III were 31.4%, 56.4%, and 12.2%, respectively. 99.6% and 63.0% received surgery and radiation therapy. Five-year DFS rates were 76.8% for TN and 89.0% for the non-TN groups (p < 0.001), while five-year recurrence rates were 18.8% for TN and 11.2% for non-TN groups (p < 0.001). The median DFS was significantly shorter for TN than non-TN patients (836 vs. 869 days, p < 0.0001). The multivariate Cox models showed that the likelihood for DFS was lower for TN (HR = 0.37, p < 0.0001), and risk for recurrence was higher for TN (HR = 2.85, p < 0.0001), as compared to non-TN group. Conclusions: Based on data from a U.S. localoncology practice, this study found TN status was associated with shorter DFS and higher risk of recurrence among early-stage BC patients despite CT. The results emphasize the need for more potent treatment for TNBC. The results need to be confirmed in other oncology practices. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration sanofi-aventis sanofi-aventis sanofi-aventis sanofi-aventis