Clinical Course of Breast Cancer Patients With Complete Pathologic Primary Tumor and Axillary Lymph Node Response to Doxorubicin-Based Neoadjuvant Chemotherapy
Henry M. Kuerer, Lisa A. Newman, Terry L. Smith, Fred C. Ames, Kelly K. Hunt, Kapil Dhingra, Richard L. Theriault, Gurpreet Singh, Susan M. Binkley, Nour Sneige, Thomas A. Buchholz, Merrick I. Ross, Marsha D. McNeese, Aman U. Buzdar, Gabriel N. Hortobagyi, S. Eva Singletary- Cancer Research
- Oncology
PURPOSE: To assess patient and tumor characteristics associated with a complete pathologic response (pCR) in both the breast and axillary lymph node specimens and the outcome of patients found to have a pCR after neoadjuvant chemotherapy for locally advanced breast cancer (LABC).
PATIENTS AND METHODS: Three hundred seventy-two LABC patients received treatment in two prospective neoadjuvant trials using four cycles of doxorubicin-containing chemotherapy. Patients had a total mastectomy with axillary dissection or segmental mastectomy and axillary dissection followed by four or more cycles of additional chemotherapy. Patients then received irradiation treatment of the chest-wall or breast and regional lymphatics. Median follow-up was 58 months (range, 8 to 99 months).
RESULTS: The initial nodal status, age, and stage distribution of patients with a pCR were not significantly different from those of patients with less than a pCR (P > .05). Patients with a pCR had initial tumors that were more likely to be estrogen receptor (ER)–negative (P < .01), and anaplastic (P = .01) but of smaller size (P < .01) than those of patients with less than a pCR. Upon multivariate analysis, the effects of ER status and nuclear grade were independent of initial tumor size. Sixteen percent of the patients in this study (n = 60) had a pathologic complete primary tumor response. Twelve percent of patients (n = 43) had no microscopic evidence of invasive cancer in their breast and axillary specimens. A pathologic complete primary tumor response was predictive of a complete axillary lymph node response (P < .01). The 5-year overall and disease-free survival rates were significantly higher in the group who had a pCR (89% and 87%, respectively) than in the group who had less than a pCR (64% and 58%, respectively; P < .01).
CONCLUSION: Neoadjuvant chemotherapy has the capacity to completely clear the breast and axillary lymph nodes of invasive tumor before surgery. Patients with LABC who have a pCR in the breast and axillary nodes have a significantly improved disease-free survival rate. However, a pCR does not entirely eliminate recurrence. Further efforts should focus on elucidating the molecular mechanisms associated with this response.