The correlationship of Ki-67 with clinical pathological characteristics and efficacy of neoadjuvant chemotherapy in breast cancer

Objective To analyze the impact of clinical pathological factors on efficacy and prognosis of primary breast cancer patients treated with neoadjuvant chemotherapy(NCT), and explore the predictive factors affecting the efficacy of neoadjuvant chemotherapy in breast cancer. Method A total of 320 patients with locally advanced breast cancer were enrolled in this study. And the status of cancer tissue ER, PR, HER2 and Ki-67 in these patients were retrospectively reviewed. The patients received surgery after 4- 6 cycles of NCT. We analyzed the relationship between clinical pathological characteristics and pathologic complete response(p CR). Parameter of clinical pathological and analysis of curative effect were performed by χ2test. Prognostic factors were determined by COX multivariate regression. Result Ki-67 index negatively correlated with ER(r=- 0.174, P=0.002)/PR(r=- 0.132, P=0.019) expression. Higher Ki- 67 index was associated with larger tumor size(r=0.132, P=0.019) and HER2 overexpression(r=0.140, P=0.012). p CR rate was higher in ER/PR negative patients than ER/PR positive patients(respectively 26.9%vs 7.4%, χ2=22.761, P=0.000; 22.7% vs 10.9%; χ2=7.950, P=0.005). patiens with Ki-67 high expression had higher p CR rate than those with Ki-67 low expression,(18.0% vs 8.6%, χ2=4.552, P=0.033). patiens with Ki-67 decreased group after neoadjuvant chemotherapy got higher p CR rate than those Ki-67 undecreased group,(19.8% vs 1.3%, χ2=15.356, P=0.000). Molecular subtype exerted a differential effect on response to NCT. Patients in Luminal A got lower p CR rate 1.4%(1/71). Compared with Luminal B 15.3%(25/163), HER2 overexpression subtype 31.3%(14/45),and triple- negative phenotype 22.0%(9/41).( χ2=20.639, P=0.000). Patients with Ki- 67 low expression had longer DFS(P=0.034) and OS(P=0.034) than those with Ki-67 high expression. Conclusion Ki-67 high expression correlated with better response to NCT but worse prognosis. Ki-67 expression and Ki-67 change after chemotherapy are independent prognostic(DFS)factors. ER, PR, Ki-67 and molecular subtype may be the predictive factors of NCT effect.Ki-67 index associated with ER, PRand HER2.