[209] Predicting Non-Sentinel Lymph Node Status in Breast Cancer Patients with Metastases in Sentinel Lymph Nodes

Aoife J McCarthy, Kate O'Connor, Fionnuala O'Connell, Michael W Bennett, Tara Jane Browne. Cork University Hospital, Cork, Ireland

Background: Current practice is to perform a completion axillary lymph node dissection (ALND) for breast cancer patients with positive sentinel lymph nodes (SLNs), although fewer than half will have non-sentinel lymph node (NSLN) metastasis.
Our aim was to assess morphologic features of the SLN metastasis to elucidate those features that might predict NSLN involvement, thereby isolating a subgroup of patients with SLN metastases in whom ALND is not necessary.
Design: Reports from all patients who underwent SLN biopsy (SLNB) over a 1 year period were analyzed for: type, grade and size of primary tumor, and lymphovascular space invasion (LVI).
The tumor deposits within the positive SLNs were reviewed for: location (subcapsular, parenchymal, combination of subcapsular and parenchymal, and extensive), size, percentage of SLN involved, necrosis, desmoplasia, overall Modified Bloom-Richardson grade, extranodal extension, extranodal LVI, mitotic count (number of mitoses per 300 cells) and proliferative index (Ki-67 count per 10 high power fields (hpfs) and per 300 cells).
Statistical analysis was performed using a statistical software package (SPSS).
Results: 331 patients had a SLNB. 71 SLNs were positive (neo-adjuvant treated patients were excluded) and these proceeded to have ALND (21 ALNDs were positive).
Having a positive SLN was statistically significantly associated with: type (P=0.002), grade (P<0.001), and size (P<0.001) of primary tumor, and LVI (P<0.001).
Tumor deposits within SLNs exhibiting a desmoplastic response were more likely to have positive ALND specimens (P=0.009).
Positive ALND was not statistically significantly associated with: size of deposit, percentage of SLN involved, necrosis, overall Modified Bloom-Richardson grade, extranodal extension, extranodal LVI, mitotic count and proliferative index.
Both subcapsular and extensive deposits were more likely to be associated with positive ALNDs (however, P=0.245).
Ki-67 and mitotic counts per 300 cells of deposit in SLN had no statistically significant difference across positive and negative ALND groups. The positive ALND group had a higher Ki-67 count per 10 hpfs than the negative ALND group (however, P>0.05).
Conclusions: Similar to previous studies, patients with a low probability of having a positive SLN can be identified from known pathologic features of the primary tumor.
Based on the statistical significance of desmoplasia, the presence of desmoplasia within the SLN deposit appears to predict NSLN involvement, thereby potentially isolating a subgroup of patients with SLN metastases in whom ALND is indeed necessary.
Category: Breast

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 14, Wednesday Morning

 

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