A study of triple-negative breast cancer at a cancer institute in India.

Abstract

e11548 Background: Triple negative breast cancer (TNBC) has been identified as an independent poor prognostic factor for survival. Data from India is lacking. The aim of this study was to compare the clinico-pathological characteristics and treatment outcomes of patients with TNBC and non-TNBC. Methods: We did a retrospective study of 636 patients with invasive breast cancer between June 2005 and July 2009 in whom estrogen receptor, progesterone receptor and Her-2Neu status were available. Event free survival (EFS) and overall survival (OS) were defined as the time period from diagnosis to occurrence of event and death respectively. Relapse, progression or metachronous breast cancer were taken as events. Chi-square/Fischer Exact test for categorical and t-test for non-categorical variables, Kaplan-Meier curves and log-rank test for survival analysis and Cox proportional hazards model for univariate and multivariate analysis were used. Results: 155(24.4%) patients had TNBC. Patients with TNBC had significantly lower median age (46.6 vs 49.8 yrs; p=0.005, 95% CI: 0.98 to 5.38) and higher proportion of high grade tumors as compared to non-TNBC group (43% vs 23.5%; p<0.0001). The proportion of premenopausal to post-menopausal women (1.2:1 vs 0.9:1; p=0.139), median tumor size (5.2 vs 5.1 cms; p=0.685,95% CI: -0.762 to 0.5), node positivity rate (61.7% vs 65.2%;p=0.5), stage distribution (2.8%, 31.8%, 47.7%, 17.7% vs 2.3%, 27.8%, 49.1%, 20.8% for Stage I, II, III and IV respectively; p=0.8) were not significantly different between TNBC and non-TNBC groups. After a median follow-up of 22 months, the 3 year EFS was significantly lower in TNBC group (60% vs 68%; log rank p=0.0362). 3 year OS was lower in TNBC group but not statistically significant (74% vs 84%; p=0.139). Age<49 yrs, higher nodal stage and larger tumor size (>5cms) but not triple negativity were significant negative prognostic factors by multivariate analysis for EFS and OS. Conclusions: TNBC is significantly associated with younger age and high grade tumors. Triple negativity was a significant poor prognostic factor by univariate analysis for EFS but not OS. This may be due to small sample size and rather short follow-up.