Lawrence Ku, MD1, Timothy Yoo, MD1, Cameron S. Sikavi, MD2, Jonathan Kung, MD1, Linda A. Hou, MD1, Sofiya Reicher, MD, FACG1, Viktor E. Eysselein, MD, FACG1
1Harbor UCLA Medical Center, Torrance, CA; 2Cook County Health and Hospital Systems, Chicago, IL
Introduction: 2018 ACG guidelines recommend surgical evaluation for pancreatic cysts with high-risk features. Integrated Molecular Pathology (IMP) combines molecular and biochemical analysis with cytology to improve prediction of malignant transformation. We aim to characterize the long-term performance of IMP.
Methods: All pancreatic cystic lesions from prospectively acquired patients with EUS-FNA and IMP (PancraGEN, Interpace Diagnostics) from 9/2010 to 9/2013 were retrospectively analyzed. Known pancreatic adenocarcinoma, serous cystadenoma, or pseudocyst were excluded. Data on patient demographics; EUS and cross-sectional imaging; cyst fluid biochemical and molecular analysis; and cytology were collected. Cystic lesions with low malignant potential were classified as “benign” or “statistically indolent” by IMP and “statistically higher risk” or “aggressive” for those with high malignant potential. Final diagnosis was based on surgical pathology when available, repeat biopsy or imaging, and on length of clinical follow up.
Results: 69 patients with mean age 69.9; 36.2% male were included. Median follow-up was 68.5 months (0.4-99.6); 3 patients were lost to follow-up. Average cyst size was 2.3 cm (0.2-15.3). 22/69 (31.9%) cysts were in the head, 13/69 (18.8%) in the neck, 23/69 (33.3%) in the body, and 11/69 (15.9%) in the tail of the pancreas. 10 patients underwent resection or enucleation.
IMP classified 38/69 (55.1%) as benign, 27/69 (39.1%) as statistically indolent, 1/69 (1.4%) as statistically higher risk, 2/69 (2.9%) as aggressive, and 1/69 (1.4%) as indeterminate. Final diagnosis was pancreatic adenocarcinoma in 5/69 (7.2%), mucinous cystadenoma in 10/69 (14.5%), branch type IPMN in 37/69 (53.6%), serous cystadenoma in 13/69 (18.8%), and indeterminate in 4/69 (5.8%). Final diagnosis of adenocarcinoma was in 2/38 (5.3%) classified as benign by IMP, 2/27 (7.4%) statistically indolent lesions, 0/1 (0%) statistically higher risk lesions, 1/2 (50%) aggressive lesions, and 0/1 (0%) indeterminate lesions.
A composite of high malignant potential on IMP or high-risk features based on ACG guidelines yielded a sensitivity of 100%, specificity of 81.3%, PPV of 29.4%, and NPV of 100% (Table).
Discussion: Combining high-risk features based on ACG guidelines with IMP is a valuable predictor of malignant transformation of pancreatic cysts, with high sensitivity and NPV based on median 6-year follow-up, which to our knowledge is the longest reported thus far.
Citation: Lawrence Ku, MD; Timothy Yoo, MD; Cameron S. Sikavi, MD; Jonathan Kung, MD; Linda A. Hou, MD; Sofiya Reicher, MD, FACG; Viktor E. Eysselein, MD, FACG. P0029 - INTEGRATED MOLECULAR PATHOLOGY AS A PREDICTOR OF MALIGNANT TRANSFORMATION OF PANCREATIC CYSTS: A 6-YEAR FOLLOW-UP. Program No. P0029. ACG 2019 Annual Scientific Meeting Abstracts. San Antonio, Texas: American College of Gastroenterology.