Sentinel lymph node (SLN) biopsy was recently recommended after prior breast tumour surgery and lymphadenectomy is not the gold standard anymore for nodal staging after a lesion's removal. The purpose of our study was to evaluate the good practices of use of SLN biopsy in this context.

From 2006 to 2012, 138 patients having undergone a surgical biopsy without prior diagnosis of an invasive carcinoma with a definitive histological analysis in favour of this diagnosis were included in a prospective observational multicentric study. Each patient had a nodal staging following SLN biopsy with subsequent systematic lymphadenectomy.

The detection rate of SLN was 85.5%. The average number of SLNs found was 1.9. The relative detection failure risk rate was multiplied by 4 in the event of an interval of less than 36 days between the SLN biopsy and the previous breast surgery, and by 9 in the event of using a single-tracer detection method. The false negative rate was 6.25%. The prevalence of metastatic axillary node involvement was 11.6%. In 69% of cases only the SLN was metastatic. The post-operative seroma rate was 19.5%.

Previous conservative breast tumour surgery does not affect the accuracy of the SLN biopsy. A sufficient interval of greater than 36 days between the two operations could allow to improve the SLN detection rate, although further studies are needed to validate this statement.

NCT00293865.