Identification of Biomarkers Including 18FDG-PET/CT for Early Prediction of Response to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer

Purpose: To investigate the value of the metabolic tumor response assessed with F-18-fluorodeoxyglucose positron emission tomography (FDG-PET), compared with clinicobiologic markers to predict pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) in women with triple-negative breast cancer (TNBC). Experimental Design: Fifty consecutive women with TNBC and an indication for NAC were prospectively included. Different pretreatment clinical, biologic, and pathologic biomarkers, including SBR grade, the Ki-67 proliferation index, androgen receptor expression, EGF receptor (EGFR), and cytokeratin 5/6 staining, were assessed. Tumor glucose metabolism at baseline and its change after the first cycle of NAC (Delta SUVmax) were assessed using FDG-PET. Results: The pCR rate was 42%. High Ki-67 proliferation index (P = 0.016), negative EGFR status (P = 0.042), and high Delta SUVmax (P = 0.002) were significantly associated with pCR. In multivariate logistic regression, both negative EGFR status (OR, 6.4; P = 0.043) and high Delta SUVmax (OR, 7.1; P = 0.014) were independent predictors of pCR. Using a threshold at -50%, tumor Delta SUVmax predicted pCR with a negative, a positive predictive value, and an accuracy of 79%, 70%, and 75%, respectively. Combining a low Delta SUVmax and positive EGFR status could predict non-pCR with an accuracy of 92%. Conclusions: It is important to define the chemosensitivity of TNBC to NAC early. Combining EGFR status and the metabolic response assessed with FDG-PET can help the physician to early predict the probability of achieving pCR or not. Given these results, the interest of response-guided tailoring of the chemotherapy might be tested in multicenter trials. (C) 2015 AACR.