Axillary dissection can be avoided in the majority of clinically node-negative patients undergoing breast-conserving therapy, by Dengel et al.

Since the presentation of the American College of Surgeons Oncology Group (ACOSOG) Z0011 clinical trial results at the American Surgical Association 2010 meeting and the American Society of Clinical Oncology (ASCO) 2011 meeting with subsequent publications in Annals of Surgery and the Journal of the American Medical Association (JAMA), breast surgeons around the United States and indeed worldwide have been considering how to incorporate the results of this study into their clinical practice. Many breast surgeons are now forgoing axillary lymph node dissection (ALND) in selected patients undergoing breast conservation surgery (BCS) with one or two positive sentinel lymph nodes (SLN). There remains debate about what proportion of the clinical practice is subject to benefit from the Z0011 results. Even prior to the presentation of the Z0011 results, breast surgeons in the United States were increasingly avoiding ALND for those patients diagnosed with microscopic disease in the SLNs as documented both in the National Cancer Database (NCDB) as well as the Surveillance Epidemiology and End Results Registry (SEER). In the NCDB, use of SLN only in patients with micrometastatic disease increased from 25 % in 1998 to 45 % in 2005 and similarly in SEER from 21 % in 1998 to 38 % in 2004. Most recently, the results of the International Breast Cancer Study Group (IBCSG) trial 23-01, which also randomized patients with positive SLNs to ALND versus no ALND, were published. The IBCSG 23-01 study limited enrollment to patients with isolated tumor cells or micrometastatic disease; however, it did allow patients undergoing BCS or mastectomy. Interestingly, in the IBCSG 23-01 study design, 6681 patients were registered preoperatively and only 934 patients were randomized based on the operative findings. Thus, only 14 % of registered breast cancer patients met the inclusion criteria of this study. Unfortunately, the paper does not disclose the reasons for the 86 % not randomized, which is presumably mainly accounted for by node-negative patients and patients with positive SLNs with macrometastatic disease. In the manuscript entitled ‘‘Axillary Dissection Can Be Avoided in the Majority of Clinically Node-Negative Patients Undergoing Breast-Conserving Therapy,’’ the breast surgeons from Memorial Sloan-Kettering Cancer Center (MSKCC) describe their practice since adopting the Z0011 results. Over the 27-month time period from August 2010 to November 2012, they treated a total of 2,157 patients with invasive breast cancer who elected to undergo BCS for a clinical T1 or T2 breast cancer. Only 380 patients (17.6 %) were actually found to have histologic nodal metastasis and were therefore candidates for consideration of Z0011 results. Of these 380 patients, 93 did not meet Z0011 criteria because of SLN metastasis detected by immunohistochemistry only, conversion to mastectomy, or use of neoadjuvant chemotherapy. An additional 45 patients did not meet Z0011 criteria for axillary preservation (avoidance of ALND) because of the presence of metastases in more than two sentinel nodes, matted nodal disease, or extracapsular extension. Thus, overall 242 patients were able to avoid ALND as a result of incorporation of Z0011 results into the clinical practice. The authors report that ALND was avoided in 84 % of patients undergoing BCS (242 of 287). Society of Surgical Oncology 2013