Endoscopic Ultrasound, Secretin Endoscopic Pancreatic Function Test, and Histology: Correlation in Chronic Pancreatitis

OBJECTIVES: Endoscopic ultrasound (EUS) and hormone-stimulated pancreatic function tests are considered useful, and possibly complementary, in the diagnosis of early chronic pancreatitis (CP). Few past studies have compared either methods with a histological gold standard. The aims were to assess correlations of EUS score and endoscopic pancreatic function test (ePFT) results with the degree of histological fibrosis, as well as the sensitivity of each method for detecting fibrosis. METHODS: This was a retrospective study of patients who underwent EUS, ePFT, or both within 12 months of pancreatic resection or wedge biopsy. EUS scoring was performed using 9 standard criteria, with ≥4 considered abnormal. An ePFT peak bicarbonate concentration <80 mM was considered abnormal. Surgical specimens were reviewed in a blinded manner by an expert pancreatic pathologist and assigned a fibrosis score from 0 to 12. Correlations of the EUS score and ePFT peak bicarbonate with the fibrosis score are reported using the Spearman correlation coefficient. Sensitivity and specificity was calculated for each method against the histological gold standard (fibrosis score ≥2). RESULTS: Twenty-five patients were included. The fibrosis score significantly correlated with the EUS score (r=0.72; 95% confidence interval (CI)=0.43, 0.87; P<0.001) and the ePFT peak bicarbonate (r=-0.57; 95% CI=-0.81, -0.10; P=0.016). EUS had a sensitivity of 84% (95% CI=69, 100) and specificity of 100% (95% CI=40, 100) compared with histology. The ePFT had a sensitivity of 86% (95% CI=67, 100) and specificity of 67% (95% CI=13, 100). When both modalities were combined, the sensitivity increased to 100% (95% CI=63, 100). CONCLUSIONS: Both EUS and ePFT are useful tests in the diagnosis of CP. Combining EUS with ePFT may improve the sensitivity for detection of early fibrosis.