In a National Cancer Database analysis reported in JAMA Surgery, Barron et al found low pathologic nodal positivity rates among patients with clinically node-negative (cN0), HER2-positive disease or triple-negative breast cancer with breast pathologic complete response (pCR) after neoadjuvant chemotherapy. As noted by the investigators, such findings support the possibility of omitting axillary surgery in such patients.
The study involved data on 30,821 patients with cT1/cT2 cN0/cN1 breast cancer treated with neoadjuvant chemotherapy and surgical resection between January 2010 and December 2015.
Breast pCR and Pathologic Node Positivity
Of 6,802 patients with cN0 HER2-positive disease, 3,062 (45.0%) achieved breast pCR; of them, 49 (1.6%) were pathologic node–positive (ypN positive). Of 6,222 patients with cN0 triple-negative breast cancer, 2,315 (37.2%) achieved breast pCR; of them, 36 (1.6%) were ypN-positive.
Rates of ypN positivity were higher in patients with cN0 and residual disease in the breast, including 632 (16.9%) of 3,740 with HER2-positive disease and 492 (12.6%) of 3,907 with triple-negative breast cancer. Among 4,164 patients with cN1 HER2-positive disease, 1,801 (43.3%) achieved breast pCR, with 223 (12.4%) being ypN-positive. Among 3,293 patients with cN1 triple-negative breast cancer, 1,229 (37.3%) achieved breast pCR, with 173 (14.1%) being ypN-positive.
Breast pCR rates were lower in hormone receptor–positive/HER2-negative disease, with breast pCR being achieved in 646 (12.7%) of 5,069 with cN0 disease and 711 (13.5%) of 5,271 with cN1 disease. Pathologic node positivity was found in 26 (4.0%) of 646 patients with cN0 vs 217 (30.5%) of 711 with cN1 disease with breast pCR as well as in 1,464 (33.1%) of 4,423 with cN0 vs 3,775 (82.8%) of 4,560 with cN1 disease with residual disease in the breast.
The investigators concluded, “In this study, the highest rates of breast pCR were seen in ERBB2-positive disease and [triple-negative breast cancer]. In patients with cN0 ERBB2-positive disease or [triple-negative breast cancer] with breast pCR, the nodal positivity rate was less than 2%, which supports consideration of omission of axillary surgery in this subset of patients.”
This study was supported by the Mayo Clinic Kerns Center for the Science of Health Care Delivery.
Judy Boughey, MD, of the Department of Surgery, Mayo Clinic, Rochester, is the corresponding author of the JAMA Surgery article.
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