Immunohistochemical Expression of IMP3 in Superficially Invasive pT1 Esophageal Adenocarcinoma (EAC) Is Associated with Lymphovascular Invasion (LVI) and Can Help in the Risk Stratification of These Patients
Anshu Trivedi, Cecilia Gimenez, Pamela Newcomb, Jason Burghardt, Deborah Stevens, Richard W Cartun, Saverio Ligato. Hartford Hospital, Hartford, CT
Background: A problem in the management of patients with Barrett's esophagus-related pT1 EAC is to distinguish those who should be treated conservatively either by EMR(Endoscopic mucosal resection) and/or RFA (Radio-frequency ablation) from those who require gastro-esophagectomy. Recently, LVI has emerged as on of the best predictors of regional lymph node metastasis (LNM) and recurrence-free survival (RFS) in pT1 EAC (AJSP 2011; 1045:1052). However, LVI may be underestimated, both because of interobserver variability and incomplete sampling. The aim of our study was to determine whether IMP3 expression by immunohistochemistry (IHC) in pT1 EAC is associated with LVI.
Design: Depth of invasion, assessed in five sublevels (m2, m3, sm1, sm2, and sm3), LVI, and expression of IMP3 were studied in 30 patients who underwent gastro-esophagectomy for pT1 EAC (2001-2010) at Hartford Hospital, and correlated with LNM and RFS. IMP3 was considered positive when expressed in >50% of the malignant cells with an intensity of stain of 2-3+.
Results: The results are summarized in Table1. 10 of 18 (55.5%) cases with IMP3 expression demonstrated LVI and 2/10 (20%) showed LNM and DOD. In contrast, none of the 12 IMP3 negative cases showed LVI (p<0.004; 2-tailed Fisher exact test) or had LNM/DOD.