[1662] Detailed Evaluation of the Lymph Nodes in N0 Cases with Additional Levels Ought To Be Considered for the Accurate Staging of Proximal Biliary Tract Cancers

Pelin Bagci, Shishir Maithel, Sarah Fisher, Burcu Saka, Lee Ocuin, Sameer Patel, David Kooby, Charles Staley, Juan Sarmiento, Bassel El-Rayes, Leslie Ducato, Volkan Adsay. Emory University, Atlanta, GA

Background: Biliary tract cancers (BC) are notorious for very frequent local spread to lymph nodes (LNs). Oncologic operations of this region typically have a low LN yield; some advocate 6 LNs for proper staging. We hypothesized that standard pathologic LN analysis may understage patients.
Design: We identified 38 patients who underwent resection for proximal BC and had been reported as N0. Each LN (n=187) was re-reviewed in detail for metastases using 4 levels on 2 slides and immunohistochemical staining for pancytokeratin (2 levels on 1 slide).
Results: 5 of 38 patients with negative LNs on standard analysis had mets on detailed examination (13%). One patient had 2 positive LNs. LN diameters were 1.1-2.1cm, mean 1.54 cm. All positive LNs were portal with subcapsular micromets. Micromets were seen as 1 focus in 2; 2 in 1, and 4 in 2 LNs, composed of 7-cell cluster to 1.5mm nests. Fig 1:Example of a subcapsular focus of micromet.

Only 1case was revealed by IHC while the others discovered by H&E. None were missed in the original slides. Mean survival of patients with mets was 19mos vs. 30mos without mets. There was no association between LN mets detected on detailed analysis and T-stage, grade, margin-status, satellite-lesions, and perineural or lymphovascular invasion. The median number of LNs harvested was 3. One of 26 patients with <6 LNs retrieved had mets (4%), as compared with 4 of 12 patients with >6 LNs removed (33%;p=0.04). In this latter-cohort of well-staged patients, LN mets were associated with reduced median-survival of 9mos vs. 41mos (p=0.01). Fig 2:Overall survival comparison for LN positive and negative cases.

Conclusions: Considering the commonness of LN mets and well-known morphologic subtleness of BC, along with the frequent microscopic nature of mets and the clinical impact of LN-positivity on prognosis and management of the cases, it is important that the LNs of BC resections be evaluated carefully with additional levels.
Category: Liver

Monday, March 4, 2013 2:15 PM

Proffered Papers: Section E, Monday Afternoon


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