Accuracy of MDCT in preoperative definition of maximum tumour diameter in patients with gastric cancer

Purpose: The maximum tumour diameter (Dmax) is a prognostic factor in patients with gastric cancer, considering its dependence on the depth of invasion. The aim of our work has been to evaluate the accuracy of MDCT in the preoperative definition of Dmax in patients with gastric cancer, assuming surgical specimen measurements as gold standard, in order to obtain a pre- surgery prognostic evaluation. Methods and Materials: Pre-surgery CT examinations of 104 patients (mean age 68.81, range 25-90) with diagnosis of gastric cancer were evaluated retrospectively and in a blind fashion by a radiologist with expertise in the oncologic field. The Dmax measured was obtained through 2D multiplanar curved reconstruction (ADW 4.6 GE Healthcare). The results were compared with macroscopic data after surgery. Results: The mean value of Dmax obtained by surgical specimen was 57.45 mm (range 10-250) versus 70.73 mm (range 16-195.3) of Dmax measured through MDCT. If the Dmax values were stratified into three groups (group 1 smaller than 45 mm, group 2 between 45 and 80 mm, group 3 bigger than 80 mm), a correlation with MDCT results of 62.22, 65.90 and 100%, respectively, was found. Conclusion: MDCT is an accurate technique to obtain an appropriate preoperative definition of Dmax, within the limits of tumour bigger than 45 mm. The revaluation of each case with Dmax smaller than 45 mm will supply additional information about the discrepancy (retraction of the stomach following immersion into formalin, diffusion in the submucosal layer).