Selective sentinel lymph node biopsy in breast cancer local recurrence.

[INTRODUCTION AND OBJECTIVES] 5-10% of breast tumor patients develop local breast tumor recurrence. The absence of axillary re-staging could increase future local recurrence and mortality risk in these patients. The lymphoscintigraphy for sentinel lymph node biopsy in recurrences (rSLNB) using a radiotracer injection, can be an option to evaluate axillar status, but other factors known to alter the usual behaviour of SLN migration have to be taken into account, such as previous axillary surgery, breast surgery or adjuvant treatments. Our objective was to evaluate the relationship between these factors and the success rate of rSLNB (overall and aberrant drainage rates, metastases ratio).

[MATERIALS AND METHODS] 1102 patients were retrospectively evaluated in a tertiary hospital between 10/2018-04/2022. 52 patients with ipsilateral breast tumor recurrence who underwent rSLNB were included. Demographic data, tumor characteristics, previous treatments, drainage rates and characteristics were collected and analyzed (R statistical software).

[RESULTS] Overall drainage rate was 83%, in which excision was performed in 91%. Overall migration rate was significantly higher in patients with previous SLNB (92% vs 60%, p-value=0.012) and aberrant drainage was significantly higher in patients with previous axillar lymphadenectomy (ALND) (53% vs 24%, p-value=0.047). No statistical differences were observed in breast surgery or adjuvant radiotherapy. The percentage of positivity found was 13% (3 micrometastases and 2 macrometastases). 20% of metastases were found in aberrant drainage territories.

[CONCLUSIONS] rSLNB is a feasible and applicable technique in ipsilateral breast tumor recurrence, providing key information in locorregional recurrence management. A considerable percentage of metastases are located in aberrant drainage territories, which would have been missed without rSLNB. Therefore, rSLNB is essential for a correct axillary evaluation in order to trace them.