Sentinel Lymph Node Surgery After Chemotherapy Shows Accuracy in Nodal Staging in Breast Cancer

Judy C. Boughey, MD

Sentinel lymph node (SLN) surgery may provide a less-invasive alternative to axillary lymph node dissection (ALND) for nodal staging in node-positive breast cancer, according to data collected from the American College of Surgeons Oncology Group (ACOSOG) Z1071 study. These results were presented at the 35th Annual San Antonio Breast Cancer Symposium.

Most women with node-positive breast cancer—meaning that their cancer has spread to the lymph nodes—undergo ALND as a treatment, while SLN surgery is typically used for patients initially diagnosed with node-negative disease. Many patients who receive neoadjuvant chemotherapy become node-negative as the disease is eradicated in the lymph nodes. The Z1071 study was performed to determine whether SLN could be a safe method to use in patients with node-positive breast cancer who receive neoadjuvant chemotherapy.

“Many of those women will convert from node-positive disease to node-negative with the use of neoadjuvant chemotherapy,” said Judy C. Boughey, MD, associate professor of Surgery at the Mayo Clinic in Rochester, Minnesota, and lead author of the study. “These women often will ask, ‘Can I avoid the morbidity of an axillary lymph node dissection? Can I preserve some of my lymph nodes and undergo a less extensive procedure in the axilla?’”

Among the 689 patients in the study, SLNs were detected in 639 patients (92.7%). Among these patients, 637 received neoadjuvant chemotherapy, and if they were found to be node-positive, they received both SLN surgery with identification and removal of the sentinel nodes and ALND to remove lymph nodes in the axilla. The study found that 255 patients (40%) tested node-negative after receiving chemotherapy. Among the remaining 382 patients who had residual nodal disease, SLN surgery correctly identified nodal status in 326 patients; however, 56 patients who were SLN-negative tested node-positive with ALND. Thus, SLN correctly identified nodal status in 581 (255 + 326) of 637 patients (91.2%).

Boughey and her colleagues noted that the false-negative rate (FNR) representing patients who tested SLN negative but tested positive when they received ALND was 12.6%. A number of factors reduced the FNR, including the combined use of a blue dye mapping agent and a radiolabelled colloid (FRN = 10.8%) and the number of SLN examined, with patients who had more than two SLN examined having a lower FNR, including three lymph nodes (FNR = 9.0%), four lymph nodes (FNR = 6.7%), and five or more lymph nodes (FNR = 11.0%).

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Dr Judy Boughey on Reducing False Negatives in SLN Surgery

Boughey said the FNR observed in this study was encouraging, especially since this study was performed across several different institutions.

“This false-negative rate was hopefully going to be clinically acceptable to surgeons utilizing this procedure,” Boughey said. “In particular, women are very interested in trying to minimize their axillary surgery, so it is important for us to be able to have this information to give them as part of their decision-making, and to discuss what potential surgery they wish to go with.”

Boughey JC, Suman VJ, Mittendorf EA, et al. The role of sentinel lymph node surgery in patients with node positive breast cancer (T0-T4, N1-2) who receive neoadjuvant chemotherapy—results from the ACOSOG Z1017 trial. Presented at: 2012 CTRC-AACR San Antonio Breast Cancer Symposium; December 4-8, 2012; San Antonio, Texas. Abstract S2-1.

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