Incidence and clinical characteristics of patients with LAPC and mesenteric vein thrombosis and current treatment paradigm.

Abstract

714 Background: Mesenteric venous thrombosis (MVT), defined as complete occlusion of the Superior Mesenteric Vein (SMV) or Main Portal Vein (MPV) is often incidentally identified on CT or MRI in patients with Locally Advanced Pancreatic Cancer (LAPC). There is very limited data describing the incidence and treatment of MVT in large studies in this patient population. Herein, we seek to establish the incidence of MVT and the treatment response in patients with LAPC. Methods: We conducted an analysis on 180 subjects with interpretable baseline imaging for MVT enrolled in the randomized Phase III TIGeR-PaC clinical trial (NCT03257033). Subjects who completed 4 Cycles of induction treatment (3 cycles of IV gemcitabine/nab-paclitaxel and 1 cycle of IMRT or SBRT) prior to randomization were analyzed. Baseline and end of induction CT scans were read by a board-certified radiologist to determine presence of MVT. Severe MVT was defined as complete occlusion of MPV and/or SMV. For patients who completed induction the end of induction CT was used to assess down staging of MVT. We analyzed the mean age between patients with and without MVT using a Mann-Whitney test and performed a contingency table with Pearson Chi-Square statistics to analyze tumor location. Results: Out of a total of 180 patients, 91 patients presented with severe MVT at baseline (50%). There was no difference in age (67 vs. 69) or sex (44% male vs. 39% male) for patients with and without MVT. The location of the tumor in the head of the pancreas was more prevalent in both groups (62% vs 53%, respectively). Out of 112 patients who completed induction, 60 presented with MVT at baseline (53%). Seventeen of these patients (28%) demonstrated partial or complete resolution of MVT during induction; most resolved MVT after the first 2 cycles of chemotherapy (15/17). Only a minority of these patients were on anticoagulation therapy (10/60, 17%). Conclusions: Severe MVT is much more prevalent in patients with LAPC than previously reported. Anticoagulation is underutilized in this cohort; however, chemotherapy may have a beneficial effect in downstaging MVT beyond anticoagulation. Clinical trial information: NCT03257033 .