Aberrant Lymphatic Drainage in the Contralateral Axilla in Patients with Isolated Ipsilateral Breast Tumor Recurrence.

The management and implications of aberrant lymphatic drainage in the contralateral axilla during repeat sentinel lymph node biopsy (SLNB) in patients with isolated ipsilateral breast tumor recurrence (IBTR) are not well understood. We analyzed the outcomes of contralateral SLNB in cases of isolated IBTR compared to ipsilateral SLNB. We conducted a retrospective review of cases reported at Samsung Medical Center between 1995 and 2015. All patients with isolated IBTR that underwent ipsilateral and contralateral SLNB with clinically negative lymph nodes but lymphatic drainage on the ipsilateral or contralateral axilla were included. Among 233 patients with isolated IBTR, 31 patients underwent repeat SLNB, 11 underwent ipsilateral SLNB, and nine underwent contralateral SLNB. None of the patients showed contralateral axillary metastasis in cases with isolated IBTR in the absence of clinically suspicious drainage on the contralateral axilla. Contralateral drainage was associated with a longer interval to IBTR (68.4 vs.18.6 months, p = 0.001) and the overall median follow-up duration (102.6 vs. 45.4 months, p = 0.002). There was no significant difference in the recurrence after the second operation (1 of 11 vs. 1 of 9, p = 1.000). Only one patient in both groups experienced recurrence after the second operation. Two patients (22.2%) who underwent contralateral SLNB had lymphedema. We demonstrate that no patient had contralateral metastasis in patients with isolated IBTR in the absence of clinically suspicious drainage in the contralateral axilla. Further study is warranted to better understand and optimize the management of these rare and challenging cases.