Pathologic complete response (pCR) following neoadjuvant chemotherapy (NAC) has been proposed as a surrogate endpoint for of long-term clinical benefit, such as disease-free survival, event-free survival, and overall survival in patients (pts) with early breast cancer (BC). The association between molecular subtypes, clinicopathological features, and pCR rate in early BC pts treated with NAC were examined.
We retrospectively analyzed data of 208 pts undergoing NAC. Luminal A was documented in 12 pts, Luminal B in 42 pts, Her-2+ in 38 pts (Her-2+ ER-/PR- = 12; Her-2+ ER+ and/ or PR+ = 26) and triple negative breast cancers (TNBC) in 116 pts. Pathological complete response was defined as the complete disappearance of the invasive cancer in the breast and absence of tumor in the axillary lymph nodes.
The pCR rate of the entire cohort was 45%. At 4 years 95% of pts who attained a pCR were disease free compared to 78% of pts who did not (log rank test Chi2 =10.775, p < 0.01). Among TNBC subtype, at 4 years 95% of pts who attained a pCR were disease free compared to 77% of pts who did not (log rank test Chi2 =7.525, p < 0.01). On univariate analysis factors associated with higher pCR included molecular subtype (TNBC 58%, Her-2+ ER-/PR- =75%, Her-2+ ER+ and/or PR+ = 46% and Luminal A + B was 11%, Chi2 =37.03, p < 0.00000), primary tumor size (T1=62% vs. T2=46% vs. T3=16% vs. T4=18%, Chi2=15.16, p < 0.00168), nodal disease (N0=53% vs. N1=39%, Chi2=3.76, p < 0.05), age (< than 50 years = 55% vs ≥ 50 years = 39%, Chi2 = 5.05, p < 0.02) ER receptor status (neg=60% vs. pos=21%, Chi2=30.08 p < 0.00000), PR receptor status (neg=58% vs. pos=16%, Chi2=30.1 p < 0.00000), Ki67 (>40=59% vs.14-39=36% vs. <14=6%,Chi2=22.09 p < 0.00060) and stage (I = 80% vs. IIA=49% vs. IIB=40% vs. III=22%, Chi2=22.09 p < 0.0004). Menopausal status, ethnicity, extra-nodal spread and lympho-vascular invasion were not associated with a higher pCR rate. In a logistic regression model Ki-67 as a continuous variable (p < 0.02) and TNBC subtype (p < 0.04) retained its significance; while tumor size, stage of disease, nodal status, ER and PR lost significance.
TNBC molecular subtype and high Ki67 are associated with a higher pCR rate in early BC pts undergoing NAC.
The Medical Oncology Centre of Rosebank.
Has not received any funding.
All authors have declared no conflicts of interest.