Usefulness of Helical CT for the Preoperative Evaluation of Small Advanced Gastric Cancer Mimicking as Early Gastric Cancer at Endoscopy

ABSTRACT

PURPOSE: We wanted to evaluate the usefulness of helical CT, along with histopathologic correlation, for the preoperative evaluation of small advanced gastric cancers (AGCs) mimicking as early gastric cancer (EGCs) at endoscopy. MATERIALS AND METHODS: From February 2001 to September 2004, we retrospectively reviewed 17 patients with pathologically proven small AGCs that were misinterpreted as EGCs at endoscopy. The preoperative helical CT findings were prospectively analyzed and the CT staging was compared with the pathologic staging that was based on the depth of tumor invasion and status of lymph node metastasis, according to the TNM classification. RESULTS: The endoscopic findings of the 17 AGCs misinterpreted as EGCs were type IIc (n=7), IIb+IIc (n=3), IIa+IIc (n=3), IIa+IIb (n=1), and III (n=3). The mean size of the AGCs on the gross specimen was 2.8 cm (range 1.2 cm-5 cm). Helical CT clearly depicted the depth of tumor invasion by the marked transmural enhancement or the reticular strands in the exraserosal fat. Preoperative helical CT detected all 17 AGCs (100%) and it correctly diagnosed then as AGCs in 15 (88%) of 17 cases. CT staging for the T category correctly staged 12 cases (71%), it understaged four cases and it overstaged one case. Regional lymph node metastasis was positive in 11 (64%) of 17 cases on the pathologic examination. The CT staging for the N category correctly staged 10 (59%) of 17 cases, it understaged four cases, and it overstaged three cases. CONCLUSION: Preoperative helical CT correctly diagnosed small AGCs mimicking as EGCs at endoscopy. Our results show that helical CT can be useful for the decision-making during the treatment planning for those patients with gastric cancer in which the endoscopic distinction between EGC and AGC is difficult.