Introduction: Evidence from the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial suggests completion axillary lymph node dissection (cALND) after positive sentinel lymph node biopsy (+SLNB) does not improve outcomes in select patients, leading to practice variation. A multidisciplinary group of surgeons, oncologists, and pathologists developed a regional guideline for cALND which was disseminated in August 2012. We assessed the impact of Z0011 and the regional guideline on cALND rates.
Methods: Consecutive invasive breast cancer cases undergoing SLNB were reviewed at 12 hospitals. Patient, tumor, and process measures were collected for three time periods: TP1, before publication of Z0011 (May 2009-August 2010); TP2, after publication of Z0011 (March 2011-June 2012); and TP3, after guideline dissemination (January 2013-April 2014). Cases were categorized by whether they met the guideline criteria for cALND (i.e. ≤50 years, mastectomy, T3 tumor, three or more positive sentinel lymph nodes [SLNs]) or not (e.g. age > 50 years, breast-conserving surgery, T1/T2 tumor, and one to two positive SLNs).
Results: The SLNB rate increased from 56 % (n = 620), to 70 % (n = 774), to 78 % (n = 844) in TP1, TP2, and TP3, respectively. Among cases not recommended for cALND using the guideline criteria, cALND rates decreased significantly over time (TP1, 71 %; TP2, 43 %; TP3, 17 %) [p < 0.001]. The cALND rate also decreased over time among cases recommended to have cALND using the guideline criteria (TP1, 92 %; TP2, 69 %; TP3, 58 %) [p < 0.001]. Based on multivariable analysis, age and nodal factors appeared to be significant factors for cALND decision making.
Conclusion: Publication of ACOSOG Z0011 and regional guideline dissemination were associated with a marked decrease in cALND after +SLNB, even among several cases in which the guideline recommended cALND.