Endoscopic Diagnosis of Laterally Spreading Tumors in the Colorectum—A Treatment Consideration—

Abstract

Although laterally spreading tumors (LSTs) are best removed by EMR, accurate diagnosis of the submucosal (sm) invasion is clinically important. The aim of this study was to determine the endoscopic findings in a large number of LSTs with sm invasion and clarify the indications for EMR. A total of 445 colorectal LSTs resected endoscopic or surgically were evaluated retrospectively. There were 242 granular types (LST-Gs), 230 adenomas or intramucosal adenocarcinomas and 12 submucosal adenocarcinomas (sm-Ca) and 203 non-granular types (LST-NGs), 183 adenomas or intramucosal adenocarcinomas and 20 sm-Ca. Eight endoscopic findings were investigated by univariate or multivariate analysis for their possible association with sm invasion: 1. Size of tumor (≥20mm), 2. Redness, 3. Large nodule (≥10mm), 4. Depressed area, 5. Sclerous change of the wall, 6. Fold convergency, 7. Chicken skin mucosa, and 8. Pit pattern (Invasive pattern). We investigated the relation between significant endoscopic findings and the area of sm invasion. In both LST-Gs and LST-NGs, depressed area, large nodule, pit pattern and redness were significantly associated with an increased risk of sm invasion according to univariate analysis. Additionally, in LST-NGs, size and fold convergency were also significant. Furthermore in LST-Gs, large nodule was an independent risk factor for sm invasion (p=0.0001). Accuracy, sensitivity and specificity were 29 %, 83 % and 90 % respectively. In LST-NGs, Invasive pattern and size were independent risk factors for sm invasion (p<0.0001, p=0.04). Accuracy, sensitivity and specificity were 85 %, 55 % and 99 % respectively. In 90% of sm LST-Gs, penetration was found under the large nodule. On the other hand, in 45 % of LST-NGs without Invasive pattern the area of sm penetration was difficult to diagnose. Considering these data, we recommend that in LST-Gs the area including the large nodule should be resected at first. In contrast, LST-NGs should be removed en bloc for accurate histopathological diagnosis.