Axillary Recurrence after Negative Sentinel Lymphnode Biopsy; a Multicentre Cohort Study.
Authors: van Wely B. , van den Wildenberg F. , Gobardhan P. , van Dalen T. , van der Pol C. , Wijsman J. , Ernst M. , Smidt M. , Borel Rinkes I. , Strobbe L. 
Published: December 2010

Abstract
IntroductionSentinel Lymphnode Biopsy (SLNB) is generally excepted as a minimal invasive technique to stage the axilla in clinically node negative breast cancer patients. Though the reported clinically overt axillary recurrences after negative SLNB is low (0-2,8%), these false negative results after SLNB remain a concern in the treatment of pN0(slnb) breast cancer patients. In this respect many have investigated factors that may influence the risk of developing an axillary recurrence, either to explain the unexpected low incidence or to try to identify subgroups of patients with higher risk of developing an axillary recurrence. Downside to many of these studies is the single-centre study design, mostly presenting small numbers of patients with relatively short follow-up making it difficult to extrapolate the results to the every-day practice.We conducted this multicentre cohort study to identify prognostic factors for developing axillary recurrences after negative SLNB.Patients and MethodsProspectively collected data from seven large volume hospitals in the Netherlands were analyzed. Patients underwent surgery including SLNB between January 2000 and December 2002. Pathological work-up of the sentinel node, local and systemic treatment, and follow-up were performed according to Dutch National guidelines. Statistical analysis was performed to test homogeneity between the institutes. Multivariate analysis was performed to identify prognostic factors. A p-value of &lt;0,05 was considered significant.ResultsA total of 1597 patients were identified; 569 (35,6%) had positive SLNB (including micrometastasis &lt;2mm and &gt;0,2mm) and underwent Axillary Lymphnode Dissection (ALND). In the remaining 1028 patients, 986 (61,7%) were SLN negative and 42 (2,6%) patients were found to have isolated tumor cells (i.e. metastases &lt;0,2mm). In 81 of these 1028 pN0 staged patients ALND was however performed, i.e. a total of 947 SLN negative patients did not receive further axillary treatment.After a median follow-up of 77 months, eighteen patients were identified that developed clinically overt axillary recurrence (recurrence rate 1,9%). The median interval between SLNB and detection of the axillary recurrence was 37 months. Median follow-up post-recurrence was 33 months. One patient developed contra lateral breast recurrence and 9 patients developed distant metastasis (including 4 visceral metastasis). Three patients died during follow-up.Multivariate analysis showed that younger age increases (p=0,0004) and external beam radiation therapy to the breast reduces (p= 0,0012) the risk of developing an axillary recurrence. T-stage, receptor-status and number of nodes removed were not statistically significant. Adjuvant systemic therapy did not significantly influence the risk of developing an axillary recurrence in multivariate analysis.ConclusionYoung age and the absence of external beam radiation therapy to the breast both increase the risk of developing an axillary recurrence after negative SLNB.
Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1006.