Clinical Usefulness of AJCC Response Criteria in Breast Cancer Patients Who Treated with Long Course Neoadjuvant Chemotherapy

Abstract

Introduction Neoadjuvant chemotherapy (NAC) is the standard therapy for American Joint Committee on Cancer (AJCC) stage II or III breast cancer, currently. AJCC response criteria for NAC is a known useful tool for evaluating response to NAC as well as predicting survival in short course NAC. The purpose of this study is to evaluate the clinical usefulness of AJCC response criteria in long course (≥6 cycles) NAC. We also analyzed prognostic clinicopathological factors for relapse free survival (RFS) in four breast cancer subtypes.

Method From January 2009 to December 2010, a total of 183 consecutive stage II or III breast cancer patients who received NAC of 6 cycles or more were enrolled in this study. AJCC response after NAC and the clinicopathological factors of these patients were reviewed retrospectively. 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.

Result Median follow up period of 183 patients was 38.0 months. Among them, CR, PR, and NR by AJCC criteria were 22 (12.0%), 123 (67.2%), and 38 (20.8%) respectively. The 3-year RFS rates were 90.9% in CR, 80.8% in PR, and 48.5% in NR. AJCC response was significantly associated with relapse free survival (RFS) (P<0.001). After adjusting potential prognostic factors, AJCC response was independently associated with RFS (P=0.004).

Conclusion AJCC response criteria is a useful clinical predictor for RFS in long course NAC as for in short course NAC in stage II/III breast cancer.