Prognosis and treatment of micrometastatic breast cancer sentinel lymph node: a population-based study.

BACKGROUND AND OBJECTIVES: Major concern of sentinel lymph node (SLN) biopsy (SLNB) regards the prognosis of micrometastasis (Nmic) in SLN. The purpose of this study is to determine the adequate surgical treatment and prognosis of Nmic in a population-based series of breast cancer patients.METHODS: All non-metastatic breast cancer patients registered by the Modena Cancer Registry (MCR), from January 2000 to December 2008, were evaluated for SLNB. Information on patients' characteristics, treatment and follow-up was collected.RESULTS: Among 2,078 patients treated with SLNB, 28.5% (590) showed a positive SLN, subdivided in N0i+ 6.3% (31), Nmic 28.8% (176), N1 64.1% (378), and N2 0.8% (5). Of 176 Nmic, 80% (142) received an axillary lymph node dissection (ALND). Only three patients had ≥4 SLN involved. No axillary recurrence occurred in Nmic patients. The overall and disease-free survival rates were N0 99.2% and 97.7%, N0i+ 100% and 100%, Nmic 96% and 93.2%, N+ (N1 + N2) 96.1% and 92.4%, respectively (N0 vs. Nmic P < 0.001).CONCLUSIONS: This study suggests that patients with Nmic have a similar prognosis to N+ (N1 + N2) patients, and a low risk of local recurrence, questioning the necessity of ALND for Nmic SLN. J. Surg. Oncol © 2012 Wiley Periodicals, Inc