EARLY NONPOLYPOID COLORECTAL-CANCER - RADIOGRAPHIC DIAGNOSIS OF DEPTHOF INVASION

PURPOSE: To diagnose depth of invasion of early flat and depressed non polypoid colorectal cancers with double-contrast barium enema examinat ion. MATERIALS AND METHODS: Ninety-seven early nonpolypoid colorectal cancers, initially identified with colonoscopy, were investigated with double-contrast barium enema examination. Depth of invasion in resect ed specimens obtained with endoscopic mucosal or surgical resection wa s determined. Cancer confined to the mucosal layer or with focal exten sion to the submucosal layer was defined as Ca-m; moderate to massive extension of cancer into the submucosal layer was classified Ca-sm. RE SULTS: In flat elevated and depressed cancels, converging folds and se milunar deformity were observed significantly more frequently in Ca-sm than in Ca-m tumors (P < .05 and P < .01, respectively). Sensitivitie s and specificities of these findings for Ca-sm tumor were 42%, 93% an d 86%, 85%, respectively. Deep depression, irregular surface of the de pression, and tumor size larger than 20 mm were also predictive findin gs for depressed Ca-sm tumors (P < .05); the specificity of each was 1 00%. With use of these radiographic predictors, overall accuracy for d iagnosing depth of invasion was 85%. CONCLUSION: Findings on double-co ntrast barium enema study are highly predictive of depth of invasion o f early nonpolypoid colorectal cancer. Radiographic findings of conver ging folds, semilunar deformity, deep depression, irregular surface of the depression, and tumor size are predictors of Ca-sm tumor.