Response rate to neoadjuvant chemotherapy measured on imaging predicts early recurrence and death in breast cancer patients with lymph node involvements

Background The use of neoadjuvant chemotherapy for breast cancer is effective as postoperative adjuvant therapy, permits more lumpectomies, and can be used to study breast cancer biology. Although pathological response is the strongest prognostic factor, response rates vary according to various parameters, such as dissociation between breast and axillary node responses. Purpose To clarify the correlation of response rates between breast tumors and metastasized lymph nodes and to identify the clinical significance; response rates measured on imaging were evaluated among breast cancer patients with axillary lymph node involvement. Material and Methods Subjects consisted of 98 patients diagnosed with node-positive breast cancer who received chemotherapy before surgery. The response to the therapy was evaluated by changes in the largest dimensions of the breast mass and of regional lymph nodes measured on a multidetector row helical CT before and after chemotherapy. The percent reduction was calculated as a response rate. The correlation between response rate and patient outcome was analyzed retrospectively. Results Breast tumor response rates correlated statistically well with those of lymph nodes (p < 0.001). Disease-free cases had a greater tumor and/or nodal response rates than recurrence cases (p = 0.021, p < 0.001, respectively), regardless of tumor size, histological grade and HER2 amplification. Cancer-associated death was observed more frequently in cases with lower response rates compared to surviving cases (p = 0.007, p = 0.021, respectively). The prognostic difference was found most strongly in nodal response rates (p = 0.001). Conclusion The present series evaluated the therapeutic effect of NAC on breast tumors and metastasized lymph nodes, and a significant correlation with patient outcome was observed. Evaluating the response rate measured by imaging could be used as a surrogate marker for prognosis before assessment of the pathological response which is ordinarily obtained after surgery.