Outcomes of sentinel lymph node dissection alone vs. axillary lymph node dissection in early stage invasive lobular carcinoma: A retrospective study of the Surveillance, Epidemiology and End Results (SEER) database

Background: The American College of Surgeons Oncology Group (ACOSOG) Z0011 trial demonstrated no difference in local-regional recurrence (LRR), disease-specific survival (DSS) or overall survival (OS) for sentinel lymph node dissection (SLND) and completion axillary lymph node dissection (ALND) among patients undergoing breast-conserving therapy for clinical T1-T2, N0 breast cancer with 1 or 2 positive SLNs. However, Only 7% of study participants had invasive lobular carcinoma (ILC). Because ILC has a different pattern of metastases, frequently presenting as small foci requiring immunohistochemistry for detection, the applicability of ACOSOG Z0011 trial data to ILC patients is unclear. Study Design: We identified all ILC patients in the Surveillance, Epidemiology, and End Results (SEER) database (1998-2009) who met the ACOSOG Z0011 eligibility criteria. Patients were evaluated on the basis of the extent of axillary surgery (SLND alone or ALND), and the clinical outcomes of these 2 groups were compared. Results: 1269 patients (393 SLND and 876 ALND) were identified from the SEER database. At a median follow-up time of 71 months, there were no differences in OS or disease-specific survival between the two groups. Conclusion: SLND alone may result in outcomes comparable to those achieved with ALND for patients with early-stage ILC who meet the ACOSOG Z0011 eligibility criteria.