Background: The relevance of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial in patients with high-risk breast cancer has been questioned. We hypothesize that Z0011 applies to women with HER2-positive disease (HER2+), triple-negative breast cancer (TNBC), and/or age <50 years at diagnosis (YA).
Methods: Women with node-positive HER2+, TNBC, or YA were identified from a prospectively maintained database. Patients were grouped based on Z0011 trial eligibility criteria into those meeting criteria (eligible) and those who did not (ineligible). Patient and tumor characteristics were compared; survival of those meeting Z0011 criteria was determined.
Results: We identified 186 node-positive women undergoing lumpectomy/radiation for high-risk breast cancer: 57 of 186 (31 %) HER2+, 55 of 186 (30 %) TNBC, 74 of 186 (40 %) YA. Overall, 125 of 186 (67 %) met Z0011 criteria. HER2-positivity was associated with the lowest rate of ineligibility compared with TNBC and YA (16 vs. 53 and 31 %, respectively, p < 0.01). Larger tumor size, high grade, extranodal extension, and high Ki67 were associated with Z0011 ineligibility. Among those who were eligible, 105 of 125 (84 %) had ALND and 48 of 125 (38 %) had involvement of nonsentinel nodes (NSLN); median number of NSLNs involved was one (range 1-3). With median follow-up of 5.5 years, there was no difference in survival between those who had ALND and those who did not. After patients with clinically palpable nodes were excluded, 125 of 149 (84 %) met criteria.
Conclusions: The Z0011 trial eligibility requirements apply to a significant proportion of patients with HER2+, TNBC, and YA. ALND can be avoided in 67 % node-positive cases and in 84 % of those with clinically negative nodes.