Are the Conclusions of Z11 Relevant to Community Practice?

Findings of the American College of Surgeons Oncology Group (ACOSOG) Z11 trial have proven controversial, leaving physicians divided over which patients with positive sentinel lymph nodes (+SLNs) benefit from axillary lymph node dissection (ALND). We reviewed our experience at our institution with Z11-eligible patients who did not undergo ALND and explored factors that predicted for positive lymph nodes (+LNs) on ALND after 1 to 2 +SLNs to determine which patients benefit from adjuvant therapy.

All breast cancer pathology reports from our institution containing the word "sentinel" between July 1998 and December 2001 were reviewed. We obtained follow-up information on patients meeting Z11 eligibility criteria who did not undergo ALND. We also compared pathological characteristics between patients with 1 to 2 +SLNs and +LNs on ALND to those with no further +LNs.

Of the 432 pathology reports reviewed, 38 were from patients meeting Z11 criteria who did not undergo ALND. At a median follow-up of 11.9 years, these patients had 5-year overall survival (OS) of 93.3% and 10-year OS of 79.3%. No patient had recurrent disease in the axilla. Of the 80 patients with 1 to 2 +SLNs who underwent ALND, tumors with +LNs on ALND were generally larger, nonductal histology, more likely to be estrogen receptor positive (ER(+)) and progesterone receptor positive (PR(+)), and less likely to be HER2(+).

Our institution's 5-year OS (93.3%) for Z11-eligible patients closely resembled those from the Z11 trial (92.5%) and our 10-year data provide evidence of what to expect for Z11-enrolled patients with continued follow-up. Larger tumor, nonductal, ER(+), PR(+), and HER2- were predictive for further +LNs on ALND, which might reflect surgical bias.