[258] Frozen Section Evaluation of Breast Carcinoma Sentinel Lymph Nodes: A Retrospective Review of 1940 Cases

Justin S Poling, Pedram Argani, Ashley M Cimino-Mathews. Johns Hopkins Hospital, Baltimore, MD

Background: Many sentinel node biopsies (SLNB) are evaluated intraoperatively by frozen section, which may impact the need for further axillary dissection (AD). However, the need for AD in patients with small metastases has been recently called into question, raising the possibility that frozen SLNB may be unnecessary. Furthermore, frozen section can compromise tissue for further study. As a compromise at our institution, we grossly evaluate all SLNB and freeze half of the node. Here, we evaluate the frozen SLNB discrepancy rate at our institution, focusing on cause of discrepancy and need for further surgery.
Design: We reviewed surgical pathology records for all breast cancer resections with frozen section of SLNB examined from 01/2003 (n=1940). For cases with a frozen section discrepancy, we compiled clinicopathologic data including age, tumor type, tumor size, metastasis size, reason for discrepancy, and follow-up including AD and survival.
Results: In ninety-five cases (4.9%), the SLNB was called negative on frozen but positive on final examination (false negatives), as detailed below. Overall frozen SLNB sensitivity was 76.3%; specificity was 99.9%; positive predictive value was 99.7%; negative predictive value was 94.0%. Overall 42% of patients with false negative frozen SLNB were taken back to surgery for an AD; 29% of patients from 2009-12 were taken back to surgery, whereas 53% of patients from 2003-08 were taken back.

Clinicopathologic data of false negative frozen SLNB
AgeMedian 52 years, Range 22-82 years
Metastasis SizeMedian 1.05 mm, Range 0.05-16 mm
Primary Tumor TypeDuctal 64 (67.4%), Lobular 20 (21.1%), Mammary 11 (11.6%)
Primary Tumor SizeMedian 1.7 cm, Range 0.1-6.0 cm
Survival (as of 10/1/2012)Alive 88 (92.6%), Dead (7.4%)
Discrepancy ReasonIHC Needed 19 (20%), Block Sampling 33 (34.7%), Tissue Sampling 37 (38.9%), Interpretation 6 (6.3%)
Additional Axillary Dissection PerformedYes 39 (41.9%)*
* positive nodes found in 6/39 additional dissections


Conclusions: The protocol of freezing one half of a SLNB is a reasonable method, with a low false negative rate. The majority of missed metastases are isolated tumor cells or micrometastases. The main adverse outcome is the need for separate AD; however, additional positive nodes are uncommonly found. The trend over time of fewer patients getting additional AD after a discrepant frozen SLNB suggests that clinicians may be using this information differently in recent years.
Category: Breast

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 26, Tuesday Morning

 

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