Abstract P1-01-29: Clinical and Histopathological Factors Affecting Failed Sentinel Node Localization in Axillary Staging for Breast Cancer

Abstract

Abstract Background: Sentinel lymph node biopsy (SLNB) has become the standard of care in axillary staging of clinically node-negative breast cancer patients. We hypothesize that clinical parameters are associated with failure to identify an axillary sentinel lymph node. Methods: We performed a retrospective review of 164 consecutive breast cancer patients who underwent SLNB from March 2008 to January 2010. A superficial injection technique was used as advocated by the UK National Training Programme (NEW START). All patients had lymphoscintigrams. Delayed imaging was performed if initial lymphoscintigram was negative up to 22 hours post-injection. Patient/surgical data, histopathological data and tumour location data were recorded. A univariate and multivariate analysis was performed. Results: Mean time from radiocolloid injection to surgery was 785.10 minutes (SD 435.97). 9/164 patients failed to show nodes on delayed imaging. In 2/9 patients successful SLNB was carried out following subareolar blue dye injection and 5 minute massage. 6/9 patients showed no evidence of radioactivity or blue dye. These patients underwent a stage 2 axillary clearance. 5/6 had multiple node involvement. Age and nodal status were significant factors (P<0.05). For every unit increase in age there was a 9% (CI, 0.84 - 0.99) reduced chance of failed sentinel node localization. Patients with negative nodal status had a 90% (CI, 0.02 - 0.99) reduced risk of failed sentinel node localization than patients with nodal macrometastasis and extracapsular nodal invasion. Weight (p=0.063, CI 0.91 - 1.03), previous breast surgery (p=0.062, CI 0.006 - 1.136) and tumour location (p=0.402, CI 0.03 - 4.17) showed weak association but failed to reach statistical significance. Discussion: Our results suggest that aberrant lymphatic flow secondary to tumour burden increase the chance of failed axillary sentinel node localization. Review of lymphoscintigrams showed that in all failed localizations the radiocolloid persisted around the injection site, showing limited local diffusion only. Similar findings were observed for blue dye injection. We further hypothesize that technical factors at the time of the injection may also play a role. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-29.