ASSESSMENT OF DEPTH OF GASTRIC CANCER INVASION BY ENDOSCOPIC ULTRASONOGRAPHY (EUS) WITH SPECIAL REFERENCE TO PATHOLOGICAL FINDINGS OF MISDIAGNOSED CASES

Abstract

The ability of EUS to diagnose the depth of cancer invasion was investigated in 183 patients with gastric cancer, consisting of 104 early cancers, 31 advanced cancers simulat-ing early cancer and 48 Borrmann's type advanced cancers. The depth of cancer invasion was classified as the mucosa (m), submucosa (sm), muscularis propria (mp), and subserosa (ss) and serosa (s). Moreover, the depth of invasion into the submucosa and the muscularis propria were divided into 3 subtypes {(sm₁, sm₂, sm₃) and (mp₁, mp₂, mp₃)}, respectively. The results obtained were as follows ; 1) The diagnostic accuracy was 64.5% in all 183 cases ; 70.6% in m cancers, 32.1% in sm cancers, 77.8% in mp cancers, and 83.6% in ss and s cancers, respectively. The rate was significantly lower in sm cancers than in others. 2) Accuracy rates for sml, sm2 and sm3 cancers were 14.3%, 72.7% and 15.4%, respectively, and significantly lower in sml and sm₃ cancers than that in sm₂ cancers. These results caused a lower diagnostic accuracy of cancer invasion in sm cancers, compared with others. 3) In early gastric cancer, the diagnostic accuracy of diagnosing the depth of cancer invasion was significantly lower in depressed types than in elevated types and much lower with increasing size of lesion. 4) The diagnostic accuracy of cancer invasion was significantly lower in cases with fibrosis accompaning peptic ulcer or ulcer scar than in cases without them. 5) The reasons for incorrect assessment of cancer invasin by EUS were fibrosis accompaning peptic ulcer in 29.2%, microinvasion in 24.6%, and massive invasion into the submucosa in 15.4%. The 3 above factors accounted for approximately 70% of incorrect diagnosis by EUS.