EUS and secretin endoscopic pancreatic function test predict evolution to overt structural changes of chronic pancreatitis in patients with nondiagnostic baseline imaging

Background and Objectives: The accuracy of EUS and endoscopic pancreatic function test (ePFT) for diagnosis of early or minimal-change chronic pancreatitis (MCCP) is poorly understood. We hypothesized that the natural history of the disease may be used as a 'gold standard' to assess the ability of EUS and ePFT to predict the eventual development of overt chronic pancreatitis (CP) changes on computed tomography/magnetic resonance cholangiopancreatography (CT/MRCP). The aim of the study was to determine the ability of EUS and ePFT to predict disease progression in patients with suspected MCCP who had nondiagnostic baseline imaging. Methods: A retrospective cohort study was conducted. Patients who underwent EUS and ePFT for suspected CP and who had nondiagnostic CT or MRCP were included. Patients without repeat imaging performed more than 1 year after their initial EUS/ePFT were excluded. Imaging was considered diagnostic if calcifications, main duct dilation (Cambridge Class III/IV), or severe atrophy were identified. Patients lost to follow-up were contacted to complete a survey documenting current symptoms and whether patients progressed to CP based on imaging. Univariable and multivariable analyses were performed using Cox regression. Results: Two hundred and thirty patients who underwent EUS/ePFT for suspected MCCP were identified between 2006 and 2012. Of these, 90 had a non-diagnostic baseline imaging test and subsequently a follow-up imaging test greater than 1 year later. These 90 patients constituted our study population. During a mean follow-up of 7 years, 19 (21%) patients developed CP by histology and imaging. Abnormal ePFT (peak bicarbonate <80 mmol) was a significant predictor of progression (hazard ratio [HR]: 4.7, confidence interval [CI]: 1.8, 12.4). Likewise, EUS Rosemont classification 'suggestive/most-consistent' was a significant predictor of progression (HR: 7.3, CI: 2.4, 22.1). Conclusions: In patients with abdominal pain of suspected pancreatic origin and with nondiagnostic cross-sectional imaging, EUS and ePFT results predict the development of classic CP structural changes over time. These results support EUS and ePFT as effective tools for predicting progression of minimal change to overt CP.