Low Risk of Development of a Regional Recurrence After an Unsuccessful Repeat Sentinel Lymph Node Biopsy in Patients with Ipsilateral Breast Tumor Recurrence

Background: Unlike sentinel lymph node biopsy (SLNB) in the primary setting, the repeat SLNB (rSLNB) in patients with ipsilateral breast tumor recurrence (IBTR) is challenging, because it is difficult to visualize and/or harvest a sentinel lymph node in every patient. Regional treatments options and safety in terms of regional disease control after such an unsuccessful rSLNB remain unclear. This study assesses factors associated with the performance of axillary lymph node dissection (ALND) after unsuccessful rSLNB and evaluates the occurrence of regional recurrences. Methods: Data were obtained from the Sentinel Node and Recurrent Breast Cancer (SNARB) study. In 239 patients, the rSLNB was unsuccessful, of whom 60 patients underwent ipsilateral ALND. Results: A shorter time interval between primary treatment and IBTR, and a primary negative SLNB were significantly associated with a higher probability to be treated with ALND after unsuccessful rSLNB (P < 0.001). The 5-year regional-recurrence rate was 0.0% in the ALND group compared with 3.7% in the group treated without ALND (P = 0.113). Of the 179 patients treated without ALND, after a median follow-up of 5.1 years (range 0.3–13.2), 7 (3.9%) developed a regional recurrence as first event after unsuccessful rSLNB. None of the seven recurrences occurred in the ipsilateral axilla. Univariable analysis showed no factors associated with regional recurrence as first event after unsuccessful rSLNB (P > 0.05). Conclusions: The present study demonstrates that the risk of regional recurrence in patients with an IBTR and an unsuccessful rSLNB is negligible, irrespective of the use of ALND. This suggests that there is no need for additional treatment of the axilla after an unsuccessful rSLNB.