The diagnostic accuracy and strength of agreement between endoscopic ultrasound and histopathology in the staging of ampullary tumors

Data were collected retrospectively. We included patients with an ampullary tumor who underwent EUS and surgical resection. Tumor (T) and nodal (N) TNM staging for EUS and histopathological (HP) staging were compared.

From 2009 to 2010, a total of 79 patients with ampullary tumors were identified. Of these, 26 had both EUS and Whipple’s surgery and were included (28 did not undergo resection, 13 had palliative surgery only and 12 had resection without EUS). For T staging by HP, there were 2 (7.7 %) T1, 11 (42.3 %) T2, 12 (46.2 %) T3 and 1 (3.8 %) T4 tumors. The accuracy of EUS T staging was 73.1 % with a Kappa value of 0.564 (p < 0.0001). The sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV) of EUS, respectively were 50.0 %, 91.7 %, 33.3 % and 95.7 % for T1 tumors; 81.8 %, 80.0 %, 75.0 % and 85.7 % for T2; 75.0 %, 92.9 %, 90.0 % and 81.3 % for T3 tumors. For N staging by HP, 17 (65.4 %) were N0 and 9 (34.6 %) N1. The N staging diagnostic accuracy was 80.8 % with a Kappa value of 0.586 (p = 0.003). The sensitivity, specificity, PPV, NPV for N0 disease were 82.4 %, 77.8 %, 87.5 % and 70.0 %, respectively while for N1 they were 77.8 %, 82.4 %, 70.0 % and 87.5 %, respectively.

EUS had a moderate strength of agreement with histopathology for both T and N staging, and a high diagnostic accuracy for nodal staging.