Discordance between number of scintigraphic and perioperatively identified sentinel lymph nodes and axillary tumour recurrence

Abstract Background In breast cancer, sentinel node biopsy is considered the standard method to assess the lymph node status of the axilla. Preoperative identification of sentinel lymph nodes (SLN) is performed by injecting a radioactive tracer, followed by lymphoscintigraphy. In some patients there is a discrepancy between the number of lymphoscintigraphically identified sentinel nodes and the number of nodes found during surgery. We hypothesized that the inability to find peroperatively all the lymphoscintigraphically identified sentinel nodes, might lead to an increase in axillary recurrence because of positive SLNs not being removed. Methods Patients who underwent sentinel node biopsy between January 2000 and July 2010 were identified from a prospectively collected database. The number of lymphoscintigraphically and peroperatively identified sentinel nodes were reviewed and compared. Axillary recurrences were scored. Results 1368 patients underwent a SLN biopsy. Median follow up was 58.5 months (range 12–157). Patient and tumour characteristics showed no significant differences. In 139 patients (10.2%) the number of radioactive nodes found during surgery was less than preoperative scanning (group 1) and in 89.8% ( N  = 1229) there were equal or more peroperative nodes identified than seen lymphoscintigraphically (group 2). In group 1, 0/139 patients (0%) developed an axillary recurrence and in the second group this was 25/1229 (2.0%) respectively. No significant difference between groups regarding axillary recurrence, sentinel node status and distant metastasis was found. Conclusion Axillary recurrence rate is not influenced by the inability to remove all sentinel nodes during surgery that have been identified preoperatively by scintigraphy.