Potential impact of application to the Z0011 trial on the omission of axillary lymph node dissection in women undergoing sentinel node biopsy: a retrospective cohort study
Abstract Background To evaluate the number of patients with early-stage breast cancer, undergoing axillary lymph node dissection for metastatic sentinel lymph nodes, who could benefit from the omission of axillary surgery following the application of ACOSOG Z0011 trial criteria.Methods A retrospective cohort study conducted in the Women’s Hospital of the State University of Campinas. The study population included 384 women diagnosed with early-stage invasive breast cancer, clinically negative axilla, treated with breast-conserving surgery and sentinel lymph node biopsy, radiation therapy, chemotherapy and/or endocrine therapy, from January 2005 to December 2010. ACOSOG Z0011 trial criteria were applied to this population and statistical analysis was carried out to make a comparison between populations.Results A total of 384 patients underwent breast-conserving surgery and sentinel lymph node biopsy. Of the total number of patients, 86 women underwent axillary lymph node dissection for metastatic sentinel lymph nodes. One patient underwent axillary node dissection due to a suspicious SLN intra-operatively. Among these patients, 82/87 (94.3%) had one to two involved sentinel lymph nodes and met criteria for the ACOSOG Z0011 trial with the omission of axillary lymph node dissection. Among the 82 eligible women, there were only 13 cases (15.9%) of lymphovascular invasion and 62 cases (75.6%) of tumors measuring up to 2cm in diameter (T1).Conclusions When eligibility for ACOSOG Z0011 trial criteria was retrospectively exported to our study population, 94.3% of the patients with one to two positive sentinel lymph nodes would benefit from the omission of axillary lymph node dissection. The high rate in our study may be explained by the large number of patients with tumors up to 2.0 cm in size and the small rate of lymphovascular invasion, which are indicative of a favorable prognosis.