The Prognostic Effect of Changes in Tumor Stage and Nodal Status After Neoadjuvant Chemotherapy in Each Primary Breast Cancer Subtype.

BACKGROUND

Although the prognostic value of pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) depends on the intrinsic subtype of breast cancer, it is not clear whether chemosensitivity itself, shown by a decreasing tumor burden after NAC, contributes to improved prognosis in primary breast cancer patients, especially in patients with non-pCR. The aim of this study was to assess the prognostic effect of changes in tumor stage or nodal status after NAC in each primary breast cancer subtype.

PATIENTS AND METHODS

We assessed 719 consecutive patients with primary breast cancer who underwent surgical resection after NAC between 2001 and 2010. The patients were divided into 5 subtypes according to their hormone receptor (HR) status, HER2 status, and nuclear grade (NG; 1/2 = low, and 3 = high).

RESULTS

In patients with HR-positive (HR)/HER2/NG-low tumors, regardless of change in tumor size, the loss of node positivity after NAC significantly improved disease-free survival (DFS). In patients with HR/HER2/NG-high tumors, achievement of tumor downstaging as well as the loss of node positivity improved their DFS. In patients with HR/HER2 tumors, tumor downstaging and the loss of node positivity significantly improved DFS, despite a non-pCR. In contrast, in patients with HER2 tumors, changes in tumor stage or nodal status were not associated with prognosis unless pCR was achieved.

CONCLUSION

Our results revealed that changes in tumor stage and nodal status after NAC might be prognostic markers in patients with HR/HER2/NG-high tumors or HR/HER2 tumors, even if there are residual tumors in the breast.