Clinical Usefulness of AJCC Response Criteria for Neoadjuvant Chemotherapy in Breast Cancer

Recently, the American Joint Committee on Cancer (AJCC) 7th edition proposed new response criteria for neoadjuvant chemotherapy (NAC) in breast cancer. The purpose of this study was to evaluate the clinical usefulness of AJCC response criteria. A total of 398 consecutive stage II or III breast cancer patients who received NAC were enrolled in this study. AJCC response criteria were as follows: (1) complete response (CR)—absence of invasive carcinoma in the breast and node; (2) partial response (PR)—decrease in either or both T or N stage; (3) no response (NR)—no change or increase in either or both T or N stage. Complete response, PR, and NR by AJCC criteria were 9.8, 59.3, and 30.7 %, respectively. Among the 398 patients, 337 patients were available for both paired pre- and post- breast MRI and chest CT. AJCC response criteria were significantly associated with RECIST criteria (P