J Breast Cancer.  2014 Mar;17(1):40-46.

Ki-67 as a Predictor of Response to Neoadjuvant Chemotherapy in Breast Cancer Patients

• Kim KI
• Lee KH
• Kim TR
• Chun YS
• Lee TH
• Park HK

Abstract

PURPOSE
The objectives of this study were to assess the potential value of Ki-67 in predicting response to neoadjuvant chemotherapy in breast cancer patients and to suggest a reasonable cutoff value for classifying Ki-67 expression.
METHODS
This study included 74 breast cancer patients who underwent surgery after anthracycline-based neoadjuvant chemotherapy between 2007 and 2012. We analyzed the clinical and immunohistochemical characteristics using core biopsy specimens obtained before neoadjuvant chemotherapy to determine their correlations with the response to chemotherapy.
RESULTS
A clinical complete response was observed in 6 patients (8.1%); a clinical partial response, in 44 patients (59.5%); and clinical stable disease, in 24 patients (32.4%). A pathologic complete response (pCR) was observed in 10 patients (13.5%). In univariate analysis, estrogen receptor (ER) negativity (p=0.031), human epidermal growth factor receptor 2 (HER2) positivity (p=0.040), and high Ki-67 expression (p=0.036) were predictive factors for a pCR. In multivariate analysis, Ki-67 was the only independent predictor of a pCR (p=0.049). The analysis of Ki-67 values revealed that 25% was a reasonable cutoff value for predicting the response to chemotherapy. In subgroup analysis, a higher Ki-67 value (> or =25%) was a significant predictive factor for the response to neoadjuvant chemotherapy, especially in ER-negative and HER2-positive breast cancer patients.
CONCLUSION
Ki-67 expression in breast cancer tissue may be an effective factor for predicting the response to neoadjuvant chemotherapy. We suggest that a 25% level of Ki-67 expression is a reasonable cutoff value for predicting a response to chemotherapy. Moreover, Ki-67 is a useful predictive factor for pCR, especially in patients with ER-negative and HER2-positive breast cancer.

Keyword

Breast neoplasms; Ki-67 antigen; Neoadjuvant therapy; Predictive value of tests

MeSH Terms

Biopsy
Breast Neoplasms*
Breast*
Drug Therapy*
Estrogens
Humans
Ki-67 Antigen
Multivariate Analysis
Neoadjuvant Therapy
Polymerase Chain Reaction
Predictive Value of Tests
Receptor, Epidermal Growth Factor
Estrogens
Ki-67 Antigen
Receptor, Epidermal Growth Factor

Figure

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  Figure 1 The comparison of predictive value for the response to neoadjuvant chemotherapy in breast cancer patients by receiver operating characteristic (ROC) curve analysis. The 25% Ki-67 cutoff point had the largest sum of sensitivity (71.0%) and specificity (77.1%). T=tumor size; ER=estrogen receptor; HER2=human epidermal growth factor receptor 2; AUC=area under the ROC curve.

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