Reoperative sentinel lymph node biopsy in ipsilateral breast cancer relapse.

Sentinel lymph node biopsy (SLNB) is controversial following ipsilateral breast tumour relapse (IBTR) and previous axillary surgery. We retrospectively assessed the feasibility, outcomes and utility of this procedure. Eighteen patients with IBTR who underwent reoperative SLNB were identified. Fifteen women had previously undergone axillary lymph node dissection and three SLNB for breast cancer. Twelve of 16 patients underwent successful lymphoscintigraphy (LSG). Lymphatic drainage patterns varied widely - ipsilateral axilla (5), contralateral axilla (5), and ipsilateral internal mammary (5). Two patients had drainage to more than one nodal basin. Nine of 12 patients demonstrated drainage outside of the ipsilateral axilla. Reoperative SLNB was successful in 12/18 of patients - 4 ipsilateral axilla, 1 ipsilateral internal mammary, 1 ipsilateral intramammary, 4 contralateral axilla. Two patients had sentinel nodes in multiple nodal basins. Positive sentinel node was found in one successful case (contralateral axilla) and isolated tumour cells in two (1 contralateral axilla, 1 ipsilateral internal mammary). In conclusion, reoperative SLNB is feasible. Lymphatic drainage patterns vary widely and preoperative LSG is vital to facilitate identification of sentinel nodes in unusual sites. Its prognostic and therapeutic significance warrants further study.