[176] Increased Lymphatic Vessel Density in Positive Sentinel Lymph Nodes Predicts Additional Nodal Disease in Breast Cancer

M Ghayouri, MJ Wagoner, J Kiluk, C Laronga, CE Cox, G Acs. Moffitt Cancer Center, Tampa, FL; University of South Florida College of Medicine, Tampa, FL

Background: The accuracy of sentinel lymph node (SLN) biopsy for predicting the status of axillary lymph nodes in clinically node negative breast cancer patients has been confirmed. While patients with negative SLN need no further axillary surgery, for patients who have positive SLNs, completion axillary dissection (CALND) remains the standard practice. Although the SLNs are the only positive nodes in 50-65% of these patients, currently no reliable means exist to identify patients who could be spared the potential morbidity of CALND. We investigated whether increased lymphatic vessel density (LVD) in positive SLNs can help predict the presence of additional nodal disease.
Design: We selected 127 breast cancer cases with positive SLN biopsy for the study. Lymphatic vessels in positive SLNs were detected by D2-40 immunohistochemistry and the LVD at the periphery of metastatic tumor clusters was determined by the hot-spot method. LVD in the SLNs was correlated with clinicopathologic tumor features and the presence of additional nodal metastases in subsequent CALND.
Results: SLN metastasis was confined to 1 SLN in 75 (59%) and involved more than 1 SLN in 52 (41%) cases. One hundred cases (79%) showed macrometastases, while only micrometastases were seen in 27 (21%) cases. LVD in the positive SLNs showed no correlation with tumor type, histologic grade, primary tumor size, or hormone receptor and HER2/neu expression. A significant positive correlation was seen between LVD and the size of metastatic disease in SLNs; LVD was significantly higher in SLNs involved by macro- compared to micrometastases (p<0.0001). Additional nodal disease in subsequent CALND was present in 61 (48%) cases. LVD in positive SLNs was significantly increased in cases associated with additional nodal disease on subsequent CALND both among all cases (p<0.0001) and when cases with only single positive SLNs were analyzed separately (p=0.0008). Using a cutoff at the median LVD value, the sensitivity and specificty of high LVD to predict additional nodal disease were 0.7143 and 0.7344, respectively.
Conclusions: Our results suggest that increased lymphangiogenesis as measured by LVD in SLNs involved by metastatic disease may play a significant role in further lymphatic spread of breast carcinoma. Assessment of LVD in positive SLNs may help in selecting patients who can be spared CALND and its associated potential morbidity.
Category: Breast

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 16, Tuesday Afternoon