Axillary recurrence rate in breast cancer patients with negative sentinel lymph node (SLN) or SLN micrometastases: prospective analysis of 150 patients after SLN biopsy.

OBJECTIVE: To assess the axillary recurrence rate in breast cancer patients with negative sentinel lymph node (SLN) or SLN micrometastases (>0.2 mm to <or=2.0 mm) after breast surgery and SLN procedure without formal axillary lymph node dissection (ALND). SUMMARY BACKGROUND DATA: Under controlled study conditions, the SLN procedure proved to be a reliable method for the evaluation of the axillary nodal status in patients with early-stage invasive breast cancer. Axillary dissection of levels I and II can thus be omitted if the SLN is free of macrometastases. The prognostic value and potential therapeutic consequences of SLN micrometastases, however, remain a matter of great debate. We present the follow-up data of our prospective SLN study, particularly focusing on the axillary recurrence rate in patients with negative SLN and SLN micrometastases.
METHODS: In this prospective study, 236 SLN procedures were performed in 234 patients with early-stage breast cancer between April 1998 and September 2002. The SLN were marked and identified with 99m technetium-labeled colloid and blue dye (Isosulfanblue 1%). The excised SLNs were examined by step sectioning and stained with hematoxylin and eosin and immunohistochemistry (cytokeratin antibodies Lu-5 or CK 22). Only patients with SLN macrometastases received formal ALND of levels I and II, while patients with negative SLN or SLN micrometastases did not undergo further axillary surgery.
RESULTS: The SLN identification rate was 95% (224/236). SLN macrometastases were found in 33% (74/224) and micrometastases (>0.2 mm to <or=2 mm) in 12% (27/224) of patients. Adjuvant therapy did not differ between the group of SLN-negative patients and those with SLN micrometastases. After a median follow-up of 42 months (range 12-64 months), 99% (222/224) of evaluable patients were reassessed. While 1 patient with a negative SLN developed axillary recurrence (0.7%, 1/122), all 27 patients with SLN micrometastases were disease-free at the last follow-up control.
CONCLUSIONS: Axillary recurrences in patients with negative SLN or SLN micrometastases did not occur more frequently after SLN biopsy alone compared with results from the recent literature regarding breast cancer patients undergoing formal ALND. Based on a median follow-up of 42 months-one of the longest so far in the literature-the present investigation does not provide evidence that the presence of SLN micrometastases leads to axillary recurrence or distant disease and supports the theory that formal ALND may be omitted in these patients.