Axillary lymph node surgery
The axillary lymph nodes should be staged to aid in determining prognosis and therapy. Sentinel lymph node (SLN) biopsy is the initial standard axillary staging procedure performed in women with invasive breast cancer. The SLN is defined as any node that receives drainage directly from the primary tumor, therefore, allowing for more than one SLN, which is often the case. Studies have shown that the injection of technetium-labeled sulfur colloid, vital blue dye, or both around the tumor or biopsy cavity, or in the subareolar area, and subsequent drainage of these compounds to the axilla results in the identification of the SLN in 92% to 98% of patients.[40,41] These reports demonstrate a 97.5% to 100% concordance between SLN biopsy and complete axillary lymph node dissection (ALND).[42,43,44,45]
A multicenter randomized phase III trial of 5,611 patients randomly assigned to either SLN plus ALND or to SLN resection alone with ALND only if the SLNs were positive showed no detectable difference in OS, disease-free survival (DFS), and regional control. OS was 91.8% versus 90.3% in the SLN plus ALND and SLN alone, respectively (P = .12).[Level of evidence: 1iiA]
Similarly, a single-center randomized trial of 532 patients with T1 carcinomas undergoing either SLN biopsy plus complete axillary dissection or SLN biopsy alone showed, after a median follow-up of 78 months, no difference in 5-year DFS (92.9% in the SLN biopsy without routine axillary dissection group vs. 88.9% in patients having axillary dissection irrespective of SLN findings, P = .1).[Level of evidence: 1iiDii]
The reported false-negative rates of SLN biopsy using axillary node dissection as the gold standard range from 0% to 15% with an average of 8.8%. The success rate varies with the surgeon's experience and with the primary tumor characteristics. In general, studies have restricted the use of SLN biopsy to women with T1 and T2 disease, without evidence of multifocal involvement or clinically positive lymph nodes. SLN biopsy alone is associated with less morbidity than axillary lymphadenectomy. In a randomized trial of 1,031 women that compared SLN biopsy followed by axillary dissection when the SLN was positive with axillary dissection in all patients, quality of life at 1 year (as assessed by the frequency of patients experiencing a clinically significant deterioration in the Trial Outcome Index of the Functional Assessment of Cancer Therapy-Breast scale) was superior in the SLN biopsy group (23% vs. 35% deteriorating in the SLN biopsy vs. axillary dissection groups, respectively; P = .001).[Level of evidence 1iiC] Arm function was also better in the SLN group. The NSABP-B-32 (NCT00003830) trial, a randomized study of 5,611 women, found the same results with respect to accuracy and technical success. Based on this body of evidence, SLN biopsy is the standard initial surgical staging procedure of the axilla for women with invasive breast cancer.