Risk of local-regional and distant recurrence in triple-negative T1N0 breast cancer

Abstract

609 Background: Triple-negative (TN) breast cancer (BC) has a high recurrence rate but effectiveness of current treatments is not well documented. Methods: From a prospective cohort of primary breast cancer registry patients at our institution (1999–2004), we identified a subset of TNM stage I (T1N0) BC. Estrogen (ER) and progesterone receptor (PR)/HER2/neu (HER2) negative (TN) patients (N=91) were compared to ER+/PR+/HER2- (HR+/HER2-) patients (N=770). Diagnosis and treatment variables were chart abstracted and vital and disease status was updated annually including local, regional or distant recurrence (endpoint). Length of follow-up was at least 2 years, average = 4.62 years. Pearson chi-square testing was used for bivariate evaluation of outcomes. Relapse-free survival (RFS) using any recurrence as the endpoint was evaluated using the Kaplan-Meier procedure. Results: Average patient age was 59 years (range 23–88). TN patients were more likely to receive adriamycin/cytoxan/taxane combination adjuvant chemotherapy, 25% vs. 8% (chi-square = 20.97, p =0.013). The rate of any recurrence was 9.9% in the TN group vs. 1.3% in the HR+/HER2 group (chi-square = 27.84, p<0.001) and distant recurrence was 6.6% vs. 1.0% (chi-square = 31.10, p<0.001). Of the 9 recurrences in the TN group three were local/regional and six were distant and the distribution by T stage was 0% in TN T1a (0/5), 15.4% in TN T1b (2/13), and 9.6% in TN T1c (7/73). Among the HR+/HER2- patients there were no recurrences in the T1a or T1b group and 10 in the T1c group (n=430, 2.3%). For adjuvant chemotherapy treated women the recurrence rate was 9.4% among TN patients and 1.3% among HR+/HER2- patients (Pearson chi-square = 8.27, p = 0.004). Distant metastases sites were as follows: TN; bone (3), lung (2), distant nodes (1), (n=6, 6.6%), and HR+/HER2-; bone (6), liver (1), simultaneous bone and liver (1), (n=8, 1.0%). Among all T1N0 patients, five-year RFS was 99% in the HR+/HER2- group and 88% in the TN group (log-rank test = 30.29, p<0.001). Conclusions: Overall and among adjuvant chemotherapy treated patients, TN patients had significantly worse outcomes compared to HR+/HER2- breast cancer patients. Treatment agents and modalities specifically designed for the triple-negative subgroup need to be identified and tested to equilibrate outcomes. No significant financial relationships to disclose.