Comparison of SLNB and ALND for Node+ Breast Cancer

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J Clin Oncol. 2009 Apr 13;[Epub ahead of print], KY Bilimoria, DJ Bentrem, NM Hansen, KP Bethke, AW Rademaker, CY Ko, DP Winchester, DJ Winchester


Controversy surrounds the issue of whether a completion axillary lymph node dissection (ALND) is necessary after identification of nodal metastases by sentinel lymph node biopsy (SLNB). Although current guidelines recommend completion ALND in this situation, some experts suggest that this practice provides no survival benefit and that it increases morbidity when compared with SLNB alone. Others insist that, because >50% of women have metastases in nonsentinal nodes, ALND may be prognostic and reduce the chance of recurrence.

One prospective randomized clinical trial (ACOSOG Z001) was initiated to resolve this debate. Unfortunately, the study closed early because of poor accrual. Therefore, Bilmoria et al conducted a retrospective analysis of data from the National Cancer Data Base (NCDB) to determine nodal evaluation practice patterns in the United States and to compare recurrence and survival in women who undergo SLNB alone vs SLNB with completion ALND.

Overall, 403,167 women had clinically node-negative breast cancer and underwent SLNB from 1998 to 2005. Of these, 97,314 women (24.1%) had nodal metastases and comprised the analysis cohort. Because the NCDB includes 5-year follow-up data, outcomes were assessed in women who were diagnosed from 1998 to 2000 and received follow-up from 2004 to 2006. Of the 97,314 women, 20.8% underwent SLNB alone and 79.2% underwent SLNB with completion ALND. From 1998 to 2005, a decline in performance of SLNB alone for macroscopic disease was noted (from 24.2% to 16.7%). Conversely, an increase was observed for performance of SLNB alone among women with microscopic metastases (24.7% to 45.3%).

Analysis of SLNB practice patterns was based on data from women diagnosed from 2004 to 2006. For women with macroscopic nodal metastases, factors associated with undergoing SLNB alone were older age, black race, severe comorbidities, smaller or low-grade tumors, and treatment at a non─National Cancer Institute (NCI)−designated cancer center. For women with microscopic nodal metastases, SLNB alone was more likely to be performed in women who were older, had smaller or low-grade tumors, or underwent treatment at a non–NCI-designated center. The factors associated with undergoing SLNB alone were consistent among women diagnosed from 1998 to 2000.

For patients diagnosed from 1998 to 2005, median follow-up was 63 months. In these women, no difference in axillary recurrence or survival was observed among those who underwent SLNB alone vs SLNB with completion ALND. This remained consistent for analysis based on all women, in women with macroscopic or microscopic nodal metastases, and after adjustment for clinicopathologic characteristics, adjuvant treatment, and hospital type.

Among women diagnosed from 1998 to 2000, the median number of nodes examined was comparable for women who underwent SLNB alone (n = 11) and those who had SLNB with completion ALND (n = 14). However, from 2004 to 2005, the median number of lymph nodes examined was lower among women who underwent SLNB alone (3 nodes), than among those undergoing SLNB with completion ALND (13 nodes).

Univariate analysis (among women diagnosed from 1998 to 2000) showed no significant difference in recurrence rate or survival rate in women with macroscopic nodal metastases, regardless of whether SLND alone or SLND with completion ALND was performed. However, after adjustment for clinicopathologic characteristics, a trend for worse outcomes was observed in women with macroscopic nodal metastases who underwent SLNB alone. This was true for both recurrence rate (hazard ratio [HR], 0.58; 95% CI, 0.32-1.06) and survival rate (HR, 0.89; 95% CI, 0.76-1.04). No differences in outcomes were observed among women with microscopic nodal metastases.

The analysis shows that most women in the United States with sentinel node–positive breast cancer undergo SLNB with completion ALND. However, for women with microscopic nodal metastases, and for select patients with macroscopic nodal metastases, axillary recurrence and survival rates are similar with SLNB alone.

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