The Exportability of the ACOSOG Z0011 Criteria for Omitting Axillary Lymph Node Dissection After Positive Sentinel Lymph Node Biopsy Findings: A Multicenter Study

To determine the exportability of the criteria defined by the American College of Surgeons Oncology Group Z0011 trial for selecting patients who are eligible for omitting completion axillary lymph node dissection (cALND) after a positive sentinel lymph node (SLN) biopsy result and to investigate whether not following the Z0011 criteria might affect patient outcomes. From a multicenter database, we selected 188 patients with positive SLNs and then excluded patients with positive SLNs on immunohistochemistry only. We retrospectively applied the Z0011 criteria and grouped the patients as eligible or ineligible for omitting cALND. The eligible group was compared with the cohort included in the Z0011 trial and with the ineligible group. Kaplan-Meier survival curves were calculated for each group, and univariate analyses assessed associations between the groups and clinicopathological variables. The final analysis involved 125 patients with positive SLNs. Eighty-seven patients (69.6 %) were potentially eligible for omitting cALND. The estrogen receptor status, T stage, grade, and number of positive non-SLNs were not statistically different between the eligible group and the Z0011 cohort. The ineligible group had significantly more positive non-SLNs (P = 0.01) and a lower 5-year overall survival rate than the eligible group (P < 0.001). The similarity of clinical characteristics between the Z0011 trial cohort and our eligible group confirms the exportability of these criteria to another population. The worse prognosis of patients who did not meet the Z0011 criteria suggests prudence before disregarding or enlarging broadening the indications for omitting cALND.