Repeated sentinel lymph node biopsy for local recurrence after breast-conserving surgery.

Background: In the realm of surgical therapy for cN0 early breast cancer, sentinel lymph node biopsy (SNB) has been established as a technique that allows the omission of axillary lymph node dissection (Ax) while maintaining local control in the axillary region.

Methods: This retrospective study analyzed data from 52 patients who underwent reSNB for IBTR after initial breast-conserving surgery at Kanagawa Cancer Center between June 2012 and March 2019. reSNB was conducted using both the dye and radioactive isotope methods. The identification rate was defined as the number of cases in which sentinel lymph nodes were visualized on lymphoscintigraphy images divided by the total number of cases. The identification rate was compared according to the initial surgical procedure.

Results: Overall, the identification rate for reSNB was 94.2%. The identification rate for reSNB in the axilla was higher in patients who initially underwent SNB than in those who initially underwent axillary lymph node dissection (83.3% vs. 42.9%). ReSNB positivity was observed in three patients (6.7%) in the ipsilateral axilla, whereas no metastasis was detected in the contralateral axilla or internal mammary region. Although four cases of recurrence were observed after reoperation, there was no local recurrence in the ipsilateral axillary region.

Conclusions: reSNB demonstrated high identification rates, comparable to those of initial SNB, with a low rate of positive metastasis and no local recurrence in the ipsilateral axillary region. Despite the limited number of cases, these findings suggest the clinical significance of reSNB in IBTR cases.