[234] Frozen Section Versus Touch Preparation for Intraoperative Detection of Sentinel Lymph Node Metastases from Breast Cancer: A Single Institution Experience of 396 Cases

K Kanehira, Y Zakharia, W Tan, W Liu, G Wilding, S Edge, D Tan, T Khoury. Roswell Park Cancer Institute, Buffalo, NY; Unity Hospital, Rochester, NY; MD Anderson Cancer Center, Houston, TX

Background: The single most important predictor of outcome for women with breast carcinoma is the status of the ipsilateral lymph nodes. Frozen section (FS) method applies excessive tissue sectioning which might deplete a focus of tumor metastases. The purpose of this study was to compare tumor size in SLN on FS vs. permanent section (PS).
Design: Intraoperative touch preparation (TP) or FS was performed on SLN of consecutive breast cancer patients from 2007 to 2009. The decision TP vs. FS was totally dependent on the pathologist preference. When FS was decided, 2 consecutive sections were prepared. Tumor metastases size on FS and PS were recorded. Sensitivity, specificity and overall accuracy of detecting positive SLN were calculated for FS and TP groups. Fisher's exact test, Wilcoxon rank sum test and Spearman correlation test were used for statistical analyses.
Results: There were 396 patients with SLN biopsy, 124 (31.3 %) patients had at least one positive SLN. While FS was performed on 73 patients, TP was performed on 323 patients. While the specificity was 100% for both procedures, TP had sensitivity of 54.5% and FS had sensitivity of 89.4%. The median and range of the size of the tumor metastases is outlined in Table 1.

Median and range of tumor metastases for each subgroup
Median (mm)Range (mm)P value
FS (TrP)50.25 to 11<0.0001
FS (FN)1.51 to 5
TP (TrP)7.50.09 to 27
TP (FN)1.50.3 to 10
FS, frozen section; TP, touch preparation; TrP, true positive; FN, false negative

A total of 49 positive SLNs were examined intraoperatively by FS. The tumor size on FS and PS were highly correlated (Spearman correlation coefficient 0.87 (p<0.0001). However, 3 (6.1%) cases were positive on FS and negative on PS. One case became micrometastases on PS after it was macrometastases on FS.
Conclusions: Frozen section is superior to TP as a method of testing SLN. However, 6.1% of positive SLN on FS become negative on PS. This raises the possibility that some negative SLNs on FS might have been underdiagnosed. Therefore, when FS is used, some patients could be falsely down-staged.
Category: Breast

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 47, Wednesday Morning

 

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