Sentinel node biopsy in breast cancer: Validation study and comparison of blue dye alone with triple modality localization

Background: Sentinel node biopsy (SNB) for breast cancer patients is a new technique with the potential to provide an accurate staging of the axillary nodal status while avoiding the morbidity of an axillary dissection. The objective of the present study is to validate the use of sentinel node biopsy in a New Zealand hospital and to compare the ability of patent blue dye (PB) alone with triple modality (TM) (preoperative lymphoscintigraphy, intraoperative gamma probe and intraoperative blue dye) to identify the sentinel node. Methods: A total of 104 patients who had a palpable breast lump that was confirmed to be malignant by radiology and cytology and a clinical diagnosis of stage I or stage II breast cancer, were enrolled for SNB and randomly assigned to triple modality or blue dye alone for the localization of the sentinel node. Axillary dissection was performed after the sentinel node(s) had been removed. Results: There were 63 patients in the PB group and 41 patients in the TM group. Both groups are comparable, with a similar mean age and primary tumour size. A sentinel node was identified in 57 (90%) of the PB group patients and 40 (98%) of the TM group patients. Of these 23 (37%) of the PB group and 23 (56%) in the TM group had axillary nodes positive for malignancy. There was one false negative SNB in the PB group and two false negative results in the TM group. Therefore, the PB group had an accuracy of 98% and a sensitivity of 96% compared to an accuracy of 95% and a sensitivity of 91% for the TM group. Conclusion: The results of the present study validate the use of SNB in suitable breast cancer patients. Identification and the accuracy of the sentinel node localization were similar between the two groups. Therefore, in hospital centres without adequate access to a nuclear medical facility, it would be feasible to conduct SNB using blue dye alone.