Determination of histological differentiation of pancreatic cancer by radial-scanned EUS

Background: Postoperative survival and treatment program for the patients with pancreatic adenocarcinoma is determined by histological differentiation and stage of tumor. The accuracy of preoperative morphological diagnosis depends on peculiarities of pancreas anatomic position. This fact induces to find new non-invasive criteria of diagnosis.

Aim: Make clearer EUS-criteria of histological differentiation of pancreatic cancer.

Materials and Methods: In order to assess the dependence of the EUS characteristics pancreatic cancer and degree of its differentiation we carried out retrospective multiple-factor analysis on 28 cases, including 18 well-known and 7 formulated by us EUS signs. Prospective analysis of accuracy of EUS-criteria of histological differentiation had 20 patients. Comparative method was histological investigation.

Results: We developed the regressive model that includes the qualitative estimation of the homogeneity structure, dominating echogenicity of tumor and the protrusion form of outline. According to our model, non-homogeneous structure, hyper echogenicity and smooth outlines are pointing to the highly differentiated tumor. In contrast, homogeneity, hypoechogenity of lesion, and acuminate protrusion of the outline predominate at the low differentiated tumor (priority N^o 2005103425 of 10.02.2005). The results are presented in table N^o 1 (Results of pancreatic adenocarcinoma differentiation by EUS criteria and by histological investigation).

Method characteristics for moderately differentiated adenocarcinoma: accuracy 80±18%, sensitivity 92±12%, specificity 63±22%, positive predictive value 79±18%, negative predictive value 83±17%.

	Well	Moderately	Poorly
EUS	5	13	2
Histology	4	12	4