Prevalence and Prognostic Role of Triple-Negative Breast Cancer by Race: A Surveillance Study

IntroductionEmerging research suggests a substantially greater prevalence of the adverse triple-negative (TN) subtype (human epidermal growth factor receptor [HER]2−, estrogen receptor [ER]−, and progesterone receptor [PR])−) among black patients with breast cancer. No reports however have been generated from a statewide cancer registry.Patients and MethodsThe study consisted of all black patients (N = 643) and a random sample of white patients (n = 719) diagnosed with primary invasive breast cancer (2000-2003) listed in the National Cancer Institute–Surveillance Epidemiology and End Results (NCI-SEER) Connecticut Tumor Registry (CTR). HER2 status was obtained from pathology reports submitted to the registry. Remaining data were obtained from the registry database.ResultsTN tumors were more prevalent in black compared with white patients (30.8% vs. 11.2%, respectively; P < .001.) There was a 2-fold greater frequency of ER− and PR− phenotypes among black patients, but HER2 status did not differ by race. Patients with lobular cancer were less likely to have TN breast cancer compared with patients with ductal tumors (odds ratio [OR] = 0.23; 95% confidence interval [CI], 0.10-0.58). Among patients with regional disease, black patients exhibited increased risk of death (relative risk [RR] = 2.71; 95% CI, 1.48-4.97) independent of TN status. No survival disparity was found among patients with local disease.DiscussionThese registry-based data corroborate reports that TN breast cancer varies substantially by race and histologic subtype. A survival disparity among patients with advanced disease, but not local disease, casts some doubt on TN status as an explanation for differences.ConclusionMore research is warranted to understand why black patients with advanced breast cancer may be at increased risk for death whether or not their tumors express the TN phenotype.