Sentinel node biopsy in breast cancer has a greater node positivity rate than axillary node sample: Results from a retrospective analysis

Background

Sentinel node biopsy as a surgical method of axillary staging for early breast cancer has been widely accepted as an alternative to traditional four-node axillary node sampling, and is the recommended technique by the Association of Breast Surgery in the United Kingdom. In selected units axillary sampling has been compared with either radioisotope sentinel node or blue dye only techniques with comparable node positivity rates. There are no studies directly comparing combined method sentinel node biopsy (SNB) with conventional axillary (four) node sampling (ANS).

Methods

Data for all patients undergoing axillary staging by axillary node sample or sentinel node biopsy were collected, including those proceeding to axillary clearance as a second procedure, but excluding those undergoing axillary clearance as a first procedure.

Results

From January 2005 to January 2011, 641 axillary staging procedures were performed (SNB n = 231 (36.0%), ANS n = 410 (64.0%)). Baseline tumour characteristics were similar for the two groups except for a higher frequency of breast conservation in the SNB group (95.6 vs. 75.6%; p < 0.0001). The proportion of cases with positive nodes was higher in the SNB group (20.8 vs. 14.4%; p = 0.042). In patients who had presented with symptomatic disease, there was a significantly higher node positivity rate with SNB (30.9%) than with ANS (15.5%; p = 0.002), despite similar baseline characteristics in both groups.

Conclusion

Combined method sentinel node biopsy is more sensitive at detecting low volume axillary disease than traditional four-node sample.