Outcomes of Triple-Negative Breast Cancers (TNBC) Compared with Non-TNBC: Does the Survival Vary for All Stages?

Abstract

Triple-negative breast cancer (TNBC) is associated with aggressivetumor behavior and worse outcomes. In a study at a tertiary care breast unit in a developing country, clinico-pathological attributes and outcomes of patients with TNBC were compared with (c.w.) ER, PR, and/or HER2 expressing tumors (non-TNBC). Medical records of 1213 consecutive breast cancer patients managed during 2004-2010 were reviewed. An evaluable cohort of 705 patients with complete treatment and follow-up (median 36months) information was thus identified. Patients were categorized per ER, PR & HER2 status into TNBC, and ER/PR+ and/or HER2+ groups. Clinico-pathological parameters, response to NACT, and OS & DFS were compared between TNBC and non-TNBC groups. TNBC patients (n=249) comprised 35.3% of the study cohort (n=705), and were significantly younger than non-TNBC patients (mean age 49.1±11.2y c.w. 51.8±11.3, p=0.02). The TNM stage at presentation was similar in the two groups (Stage I and II-37% c.w. 44.3%, Stage III-47.5% c.w. 39.5%, Stage IV-15.5% c.w. 16.2% in TNBC c.w. Non-TNBC; p=0.09). Tumor size (5.7±2.9cm TNBC c.w. 5.4±2.8cm non-TNBC, p=0.22) was similar but lymph nodal (cN) metastases were more frequent in TNBC (77.3% c.w. 69.8%; p=0.03). TNBC had higher histologic grade (97.1% gr II/III in TNBC c.w. 91.2% non-TNBC, p=0.01) and higher incidence of LVI (20.4% in TNBC c.w. 13.5%, p=0.03). Patient groups received similar multi-disciplinary surgical, radiation, and systemic treatment. Comparable proportion of patients in 2 groups were treated with NACT (42% c.w. 38%), which resulted in pathological complete response (pCR) in 27.5% TNBC patients c.w. 17.1% non-TNBC patients (p=0.04). Both OS (81.8±4.52 c.w. 97.90±3.87months, p<0.001) and DFS (89.2±5.1 c.w. 113.8±4.3months, p<0.001) were shorter in TNBC than non-TNBC group. On stage-wise comparison, OS differed significantly only in stage III (47.4±5.3months in TNBC c.w. 74.5±4.4 in non-TNBC; p<0.001). Univariate and multivariate analyses revealed tumor stage and IHC subtyping into TNBC c.w. non-TNBC as most important factors predictive of survival. TNBC occurred at younger age and exhibited aggressive pathology as compared to non-TNBC patients. Although patients with TNBC exhibited better chemo-sensitivity, they had worse DFS and OS compared to the non-TNBC patients. The survival of Stage III TNBC patients was significantly worse compared to non-TNBC group; while in stages I, II, and IV, survival were not significantly different.