Background: Breast conservation therapy (BCT) with sentinel lymph node (SLN) biopsy is a well-established standard of care for primary operable breast cancer; 5-10% of BCT patients will develop local recurrence (LR). The question then arises: How best to manage the axilla in the setting of LR after previous BCT and SLN biopsy or axillary dissection (ALND)?
Methods: Between 9/96 and 12/04, 117 reoperative SLN were performed for LR after BCT and either SLN biopsy or ALND more than 6 months previously. Because of wide variation in the number of nodes removed at the initial procedure, validation by backup ALND was not feasible in all cases.
Results: Reoperative SLN was successful in 64/117 (55%) patients. SLNs were identified by isotope and dye in 28/64 (44%); isotope only in 29/64 (45%); dye only in 4/64 (6%); 3/64 (5%) unknown. Positive reoperative SLN were found in 10/64 (16%) successful cases. Among 54/64 (84%) patients with negative reoperative SLNs, 23 (43%) had additional non-SLN removed concurrently: these were negative in 21/23 cases (91%). In 2/23 (9%), reoperative SLN were falsely negative: one with a positive intramammary node, and the other with a positive non-SLN palpated at surgery. Success of reoperative SLN was inversely related to number of nodes removed previously, and was more likely to be successful after a previous SLN biopsy than a previous ALND (74% vs. 38%, P = 0.0002). Non-axillary drainage was identified by lymphoscintigraphy significantly more often in reoperative SLN than in primary SLN biopsy (30% vs. 6%, P < 0.0001). There were no local or axillary recurrences at a mean follow up of 2.2 years; 6 patients developed systemic recurrence.
Conclusions: Reoperative SLN biopsy is feasible in the setting of LR after previous BCT/axillary surgery and deserves further study in this increasingly common clinical scenario. The added benefit of lymphoscintigraphy in identifying sites of non-axillary drainage may be greater in the setting of reoperative SLN than for the initial SLN procedure.