Breast cancer is the most prevalent malignancy and the second leading cause of cancer death among women in the United-States (DeSantis et al. 2011). It is well documented that breast cancer incidence is higher among Caucasian women, compared to other ethnic groups (DeSantis et al. 2011). However, several studies have noted an increased incidence, late stage at diagnosis, and poorer survival outcome among young, AA women of childbearing age diagnosed with TNBC (Stead et al. 2009; Anderson et al. 2008; Tawfik et al. 2010). TNBC is characterized by a lack of ER, PR, and HER-2/neu receptors and an aggressive, basal-like phenotype that is most prevalent among AA women (Ray & Polit 2010). The increased incidence and mortality rates in AA vs. Caucasian TNBC patients may be multifactorial, including advanced stage of disease at the time of diagnosis (Weir et al. 2003), less prompt access to medical care (Shavers & Brown 2002), and socioeconomic factors (Brawley 2002).
There are limited studies that address the issue of race and survival for women with TNBC. In one large cohort study, consisting of 6370 women identified as having triple-negative breast cancer, women with triple-negative breast cancers were significantly more likely to be non-Hispanic black (odds ratio = 1.77), under the age of 40 (odds ratio [OR], 1.53), and had worse survival, with a 5-year relative survival of only 14% (Bauer et al. 2007). Similarly, a study by Stead et al. reported that the odds of having a triple negative tumor were 3-fold higher (HR = 5.5, 95% CI 1.6, P = 0.0001) in black compared with white women (Stead et al. 2009). Contrary to these studies, our study demonstrates for the first time that there is no significant difference in OS between AA and Caucasian TNBC patients treated at the UAMS Women’s Oncology Clinic in Arkansas (HR = 1.24; 95% CI, 0.32 to 5.08; P = 0.74). An interesting observation in our cohort is the age and menopausal status of our patients, with 65% being postmenopausal and over half of the patients being age 50 or older at diagnosis, which is contrary to the previously observed association between TNBC and younger age and premenopausal status (Anderson et al. 2008; Ray & Polit 2010). In addition, we show that there is no significant difference in the likelihood of receiving adjuvant chemotherapy and radiotherapy by race. Due to the retrospective nature of our study and the limitation of our small patient population size, which may account for the non-significant differences between race and survival outcomes, no power calculations were performed. However, our cohort, like MD Anderson’s, represents a geographically uniform group of TNBC patients with similar socioeconomic and cultural risks treated with a similar multidisciplinary approach at UAMS in Little Rock, Arkansas. In that study reported by Dawood et al., 470 patients with TNBC were treated with primary systemic chemotherapy at the MD Anderson Cancer Center. Their results demonstrated that race does not significantly affect pCR rates or survival outcomes in women with TN breast cancer (Dawood et al. 2009). In addition, the authors found that the 3-year OS rate was similar between 100 black patients (68%) and 371 white/other race (62%) patients who received the same treatment conditions (P = 0.091). Further, RFS (HR = 1.08; 95% CI, 0.69 to 1.68; P = 0.747) and OS (HR = 1.08; 95% CI, 0.69 to 1.68; P = 0.735) was similar between the two races even after controlling for patient and tumor characteristics. If there is no significant difference between AAs and Caucasians in response to traditional cytotoxics, is it possible that a difference by race might exist in response to biologic agents? We conducted a small prospective phase II study using standard chemotherapy and bevacizumab in the neoadjuvant setting for locally advanced or operable breast cancer at UAMS. AAs had 75% pCR (9/12), whereas Whites had only 28% pCR (7/25; P = 0.0069), possibly in part because 100% of AA (12/12) had ductal carcinoma compared with only 64% (16/25) of Whites (P = 0.017). Further evaluation of this question is needed to address this issue (Makhoul et al. 2013).
In conclusion, to our knowledge, this is the only retrospective study that details TNBC trends in patients from Arkansas as it relates to race, stage of breast disease at diagnosis, recurrence and mortality, and overall survival. Our study provides supporting evidence that race is not a contributing factor on cancer recurrence, mortality or survival in AA and Caucasian TNBC patients. Future prospective studies, with participation from larger institutions that are represented by a diverse breast cancer population, will be necessary to increase statistical power and to clearly define whether or not race affects clinical outcomes in patients with TNBC.