[209] Correlation of Sentinel Lymph Node Metastases with Breast Tumor Grade, Harbor-UCLA Medical Center Experience: A Pathologic Cases Series with Evaluation of Tumor Size and Her2 and ER Overexpression

James Lee, Samuel French, Rose Venegas. Harbor-UCLA Medical Center, Torrance, CA

Background: Metastases to sentinel lymph nodes is an important hallmark of breast carcinoma prognosis and staging. Although tumor grading is not currently factored into the staging of breast cancer, in principle, higher grade breast carcinomas should exhibit a higher rate of metastases to sentinel lymph nodes. We report here the incidences of sentinel lymph node metastases in breast carcinomas according to their respective grades (I, II, and III) over a 2 year period from 2010 to 2012 and correlate such information to estrogen receptor (ER) immunostain positivity and human epidermal growth factor receptor 2 (Her2) overexpression.
Design: We reviewed 135 consecutive cases of sentinel lymph node biopsies from our institutional archives between 2010 and 2012. The presence of sentinel lymph node metastases, size of tumor, and Her2 and ER expression were evaluated and subsequently correlated with the tumor's histologic grade.
Results: 135 consecutive sentinel lymph node biopsies were evaluated. 22, 52, and 23 cases were scored by our institute's breast pathologists as grade I, II, and III, respectively. 7 (31.8%), 21 (41%), and 2 (8.7%) cases of grade I, II, and III respectively, showed tumor metastases. The average tumor sizes were 1.59 +/- 1.01 cm, 1.86+/-1.12 cm, and 2.24+/- 1.19 cm for grade I, II, and III breast carcinomas respectively. 4.5%, 13.5%, and 45% of grade I, II, and III breast cancers were positive for Her2 overexpression. Of the breast carcinomas that showed metastases to sentinel lymph nodes, no cases from the grade I tumors and 1 case each of the grade II and III tumors exhibited Her2 overexpression. Finally, 9.1%, 25%, and 35% of grade I, II, and III breast cancers showed less than 80% IHC staining for ER.

Differences in metastatic potential, tumor size, Her2 and ER expression between different breast carcinoma grades
Breast Cancer GradePercentage with SN* metastasesTumor size (cm)Percentage with Her2 over expressionPercentage with <80% ER staining
I31.81.59 +/-
III52.24+/- 1.194535
*SN-Sentinel Lymph Node

Conclusions: Unexpectedly, grade III breast carcinomas have a lower rate of sentinel lymph node metastases than observed in grade II breast carcinomas. Higher grade breast carcinomas were on average larger in size, more likely to exhibit Her2 overexpression, and less likely to exhibit ER expression. Finally, Her2 overexpression does not seem to correlate with an increased incidence of sentinel lymph node metastases.
Category: Breast

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 26, Monday Morning


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