Yield of EUS-FNA of Pancreatic Masses in the Presence or Absence of Chronic Pancreatitis

Abstract

Background: Evaluation of a focal pancreatic mass in the setting of chronic pancreatitis (CP) is a diagnostic challenge. The few studies conducted in this context are from Europe and the results are disappointing. Aim: 1) To compare the diagnostic yield and accuracy of EUS-FNA in the evaluation of pancreatic mass lesions in the presence or absence of CP in a North American population and 2) Identify predictors of CP prior to EUS-FNA of pancreatic mass lesions. Methods: Prospective study of 300 consecutive patients who underwent EUS-FNA of pancreatic mass lesions over a three year period. Chronic pancreatitis was defined by the presence of > 4 EUS criteria. The diagnostic yield and accuracy of EUS-FNA was compared between patients with and without CP. Multivariable logistic regression was used to identify predictors for CP. Results: Final diagnosis was adenocarcinoma in 210 (70%), benign disease in 64 (21%), other pathology in 19 (6%), and indeterminate in 4 (2%); 3 patients (1%) were lost to follow-up. CP was noted in 75/300 (25%) patients. A lower sensitivity for EUS-FNA was observed in patients with CP than those without CP (73.9% vs. 91.3%; p=0.02). While patients with CP had a higher NPV (88.9% vs. 45.5%; p<0.001), no significant differences were observed for specificity (100% vs. 93.8%), PPV (100% vs. 99.5%) and accuracy (91.5% vs. 91.4%) between those with and without CP. False negative cytology was encountered in 24 cases: 6/71 (8%) with CP versus 18/222 (8%) without CP. Patients with CP required more EUS-FNA passes to establish diagnosis versus those without CP (median, 5 versus 2; p < 0.001). On multivariable analysis, age < 50 (p <0.001), male sex (p < 0.001), black race (p = 0.001), and absence of jaundice at clinical presentation (p = 0.005) were significantly associated with CP. Conclusions: EUS-FNA has a low sensitivity for pancreatic mass lesions in the setting of chronic pancreatitis. This decreased sensitivity can be overcome by performing more number of passes at FNA which improves diagnostic accuracy. Demographic features and clinical presentation are predictive of underlying chronic pancreatitis in patients with pancreatic mass lesions. Background: Evaluation of a focal pancreatic mass in the setting of chronic pancreatitis (CP) is a diagnostic challenge. The few studies conducted in this context are from Europe and the results are disappointing. Aim: 1) To compare the diagnostic yield and accuracy of EUS-FNA in the evaluation of pancreatic mass lesions in the presence or absence of CP in a North American population and 2) Identify predictors of CP prior to EUS-FNA of pancreatic mass lesions. Methods: Prospective study of 300 consecutive patients who underwent EUS-FNA of pancreatic mass lesions over a three year period. Chronic pancreatitis was defined by the presence of > 4 EUS criteria. The diagnostic yield and accuracy of EUS-FNA was compared between patients with and without CP. Multivariable logistic regression was used to identify predictors for CP. Results: Final diagnosis was adenocarcinoma in 210 (70%), benign disease in 64 (21%), other pathology in 19 (6%), and indeterminate in 4 (2%); 3 patients (1%) were lost to follow-up. CP was noted in 75/300 (25%) patients. A lower sensitivity for EUS-FNA was observed in patients with CP than those without CP (73.9% vs. 91.3%; p=0.02). While patients with CP had a higher NPV (88.9% vs. 45.5%; p<0.001), no significant differences were observed for specificity (100% vs. 93.8%), PPV (100% vs. 99.5%) and accuracy (91.5% vs. 91.4%) between those with and without CP. False negative cytology was encountered in 24 cases: 6/71 (8%) with CP versus 18/222 (8%) without CP. Patients with CP required more EUS-FNA passes to establish diagnosis versus those without CP (median, 5 versus 2; p < 0.001). On multivariable analysis, age < 50 (p <0.001), male sex (p < 0.001), black race (p = 0.001), and absence of jaundice at clinical presentation (p = 0.005) were significantly associated with CP. Conclusions: EUS-FNA has a low sensitivity for pancreatic mass lesions in the setting of chronic pancreatitis. This decreased sensitivity can be overcome by performing more number of passes at FNA which improves diagnostic accuracy. Demographic features and clinical presentation are predictive of underlying chronic pancreatitis in patients with pancreatic mass lesions.