Predictors of regional recurrences in breast cancer patients with negative sentinel node.

Abstract

51 Background: For patients with clinically node-negative, early-stage breast cancer, sentinel lymph node biopsy (SLNB) has replaced axillary lymph node dissection (ALND) as a standard method for staging of regional lymph nodes. Regional recurrences after negative (SLNB) have generally been reported in the range of 0.5 to 2% and factors associated with regional recurrence in patients with negative SLNB are still to be elucidated. In this study, we evaluated regional recurrence rates and predictors of regional recurrences in patients with negative SLNB. Methods: Between January 2001 and December 2012, 1,322 patients with clinical node-negative invasive breast cancer less than 3cm underwent SLNB at Keio University Hospital. Of 1,322 patients with SLNB, 1,033 patients with negative SLNs were included in this study. Sentinel lymph nodes (SLNs) were detected using a combined method of blue dye and small-sized technetium-99m-labeled tin colloid. Intraoperative frozen examination was performed with hematoxylin and eosin (HE) staining. SLNs, fixed and embedded in paraffin, were additionally diagnosed with HE staining and immunohistochemical analysis. Results: Median age was 57.0 years (range, 25-89) and median tumor size was 1.9cm (range, 0.5-6.0cm). After a median follow-up of 54.8 months, there were 13 regional (1.3%) and 26 distant recurrences (2.5%). Median disease-free interval of regional and distant recurrences was 32.6 and 22.7 months, respectively (p=0.761). Higher nuclear grade (NG) was significantly correlated with regional and distant recurrences (p=0.001 and p=0.008). The rate of lymphovascular invasion (LVI) was significantly higher in patients with regional recurrences comparing with patients without recurrences (58.3% vs. 27.6%, p=0.026), however LVI was not a significant predictor of distant recurrences (p=0.072). Estrogen receptor negativity was significantly correlated with distant recurrences (p=0.013), whereas it was not associated with regional recurrences (p=0.626). Conclusions: Regional recurrences were rare in early-stage breast cancer patients with negative SLNB. LVI and NG can be used as predictive factors of regional recurrences after negative SLNB.