Value of breast cancer molecular subtypes and Ki67 expression for the prediction of efficacy and prognosis of neoadjuvant chemotherapy in a Chinese population.

e12512 Background: To determine the predictive role of breast cancer subtypes in the efficacy and prognosis of neoadjuvant chemotherapy (NCT) regimens combining taxanes and anthracyclines. Methods: Data from 240 patients with breast cancer who received surgery after 4-6 weeks of NCT were retrospectively analyzed. The patients were classified into luminal A, luminal B, HER2 overexpression and triple negative breast cancer (TNBC) as well as low Ki67 ( ≤ 40%) and high Ki67 ( > 40%) expression groups using immunohistochemistry. NCT outcome parameters were pathological complete response (pCR), clinical complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) 4 weeks after surgery. Long-term outcome parameters were disease free survival (DFS) with a follow up time of 3-56 months. Results: pCR rates were 1.6%, 13.4%, 22.6% and 23.8% in patients with luminal A, luminal B, HER2 and TNBC cancers, respectively. High pCR rates correlated with high Ki67 expression ( > 40%) (P < 0.001, HR = 0.17, 95% CI: 0.074-0.37) and negative estrogen receptor (ER) status (P< 0.001, HR = 3.74, 95% CI: 1.71-8.12) in a multivariate analysis. However, the DFS rate of luminal A breast cancer was highest compared to all other groups, but only significantly higher compared to luminal B (P = 0.035, HR = 1.480, 95% CI: 1.060-1.967) patients and correlated with Ki67 expression > 40% (P= 0.005). Conclusions: Luminal A type patients derived the least benefit from neoadjuvant chemotherapy but had better long-term prognoses. ER status and Ki67 expression served as efficacy predictors for NCT, whereas only Ki67 expression > 40% correlated with long-term treatment outcomes.