Invasion assessment in gastric carcinoma - imagistic and histopathologic combined study

Imagistic examinations have an essential role in the assessment of gastric cancer both in earlier and advanced stages. Among these, endoscopic ultrasound (EUS) especially contributes to the diagnosis by direct visualization of the tumor and to the staging and prognosis assessment through the evaluation of the gastric wall and regional lymph nodes. Computer tomography (CT) examination also has an important role, especially in advanced stages, in the assessment of the prognosis, contributing to TNM staging. The aim of this study is a comparative assessment of tumor invasion degree by these two imagistic methods and the correlation of the imagistic diagnosis with histopathologic assessment results on surgical specimens.

The basis of the study was represented by a group of 38 patients with gastric carcinoma investigated both by endoscopic ultrasound and computer tomography from which 15 cases with surgical excision of the tumor followed by microscopic examination were selected. Studied material was represented by: patients' medical charts, registers for ultrasound endoscopy and CT investigation, endoscopic and CT images, surgical excision samples and pathology reports. Tumor fragments were processed by classical histological techniques (fixation and paraffin wax embedding) and staining (HE).

Comparing the CT examination with ultrasound endoscopy results showed that CT examination overestimated the invasion grade of the gastric wall (T) but accurately defined the grade of lymph node invasion (N) and metastases (M). Comparing the results of ultrasound endoscopic examination with those from histopathological examination showed that the first method underestimated the grade of invasion of the gastric wall (T) while the latter correctly defined the grade of lymph node invasion (N) and metastases (M). Comparing CT examination results with histopathological ones showed that CT overestimated both the grade of invasion of the gastric wall (T), lymph node invasion (N) and metastases (M).

In the preoperative assessment of the invasion stage of gastric carcinoma (TNM), ultrasound endoscopy is the elective imagistic investigation for predicting the grade of invasion of the gastric wall while CT examination is a more accurate assessment of lymph node extension and metastases, the precise definition of invasion stage being only the result of histopathological examination on surgical specimens.