Optimization of sentinel lymph node biopsy in breast cancer using an operative gamma camera

BACKGROUND Sentinel lymph node (SLN) procedure is now a widely accepted method of LN staging in selected invasive breast cancers (unifocal, size </= 2 cm, clinically N0, without previous treatment). Complete axillary clearance is no longer needed if the SLN is negative. However, the oncological safety of this procedure remains to be addressed in randomized clinical trials. One main pitfall is the failure to visualize SLN, resulting in incorrect tumor staging, leading to suboptimal treatment or axillary recurrence. Operative gamma cameras have therefore been developed to optimize the SLN visualization and the quality control of surgery. CASE PRESENTATION A 44-year-old female patient with a 14-mm infiltrative ductal carcinoma underwent the SLN procedure. An operative gamma camera was used during and after the surgery. The conventional lymphoscintigraphy showed only one SLN, which was also detected by the operative gamma camera, then removed and measured (9.6 kBq). It was analyzed by frozen sections, showing no cancer cells. During this analysis, the exploration of the axillary area with the operative gamma camera enabled the identification of a second SLN with low activity (0.5 kBq) that conventional lymphoscintigraphy, surgical probe and blue staining had failed to visualize. Histological examination revealed a macrometastasis. Axillary clearance was then performed, followed by a postoperative image proving that no SLN remained. Therefore, the use of the operative gamma camera prevented an under-estimation of staging which would have resulted in a suboptimal treatment for this patient. CONCLUSION This case report illustrates that an efficient operative gamma camera may be able to decrease the risk of false negative rate of the SLN procedure, and could be an additional tool to control the quality of the surgery. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT00357487.