[1985] Does Expertise in Breast Pathology Influence the Intra-Operative Diagnosis of Breast Sentinel Lymph Nodes? An Institutional Experience

Asangi Kumarapeli, Buer Song, Lucia Balos, Elizabeth Marchetti. State University of New York at Buffalo, Buffalo, NY

Background: Metastatic carcinoma in a sentinel lymph node(s) (SLN) dictates the operative strategy for breast surgeons. In institutions still performing intra-operative (IO) SLN evaluation, a positive SLN will lead to an axillary dissection for the patient at the time of initial surgery. SLN evaluation in this setting is influenced by many factors, including sampling, tissue variability, and interpretation intraobserver variation. We sought to analyze the discordance rates on IO SLN diagnoses made by a general pathologist versus a breast pathologist.
Design: A computer based retrospective search identified 140 breast carcinoma cases with SLNs that were signed out at the Buffalo General Medical Center during a two year period, July 2010-June 2012. 129 cases had SLNs sent for IO assessment. We analyzed the discordance rate of the IO and permanent diagnoses as a quality assurance measure.
Results: A total of 140 SLNs were examined; 35 were positive (25%) for metastatic carcinoma. 129 of 140 SLNs were analyzed intra-operatively; 29 SLNs showed metastatic carcinoma on permanent sections. Of these 29, 14 were identified during IO evaluation. There were 15 false negative IO diagnoses of SLNs, a 52% false negative rate; with 3 macrometastases, 5 micrometastases and 7 isolated tumor cells (ITC) later identified on permanent sections. In this study, the sensitivity and specificity of intra-operative analysis is 48% and 100%, respectively. In this institution, IO evaluation demonstrated 114 of 129 concordant SLN diagnoses overall. When data was separately analyzed for breast pathologists versus general pathologists, breast pathologists performing IO diagnoses had a discordant rate of 7.5% compared to the general pathologist which was 16.1%.
Conclusions: We found an overall SLN diagnosis discordance rate of 11.6%, but only 6.2% when ITCs were excluded. In our review, breast pathologists have a lower discordant rate in the IO assessment of SLNs, when compared to the general pathologist. Although, this study is limited by a small sample size, we conclude that expertise in breast pathology will enhance the intra-operative diagnostic accuracy of SLNs.
Category: Quality Assurance

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 267, Tuesday Morning

 

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