Indication of Endoscopic Submucosal Dissection (ESD) for Large Colorectal Tumors Accompanied with Fibrosis in Submucosal Layer

Abstract

Background and Aims: The safety of endoscopic submucosal dissection (ESD) for colorectal tumors is gradually being established. The possibility of performing ESD for colorectal tumors sometimes depends on the existence of fibrosis in the submucosal layer, rather than only the size and location of the tumor. This study analyzed the causes and endscopic findings of fibrosis in the submucosal layer, in order to establish a therapeutic strategy for such lesions. Patients and Methods: ESD was attempted for 202 cases of colorectal neoplasm. Among these cases, 35 cases were accompanied by submucosal fibrosis. These cases were analyzed from clinico-pathological viewpoint. Results: For the ESD cases, the average lesion size was 31.6mm, and mean operating time was 62.8min . We had only one case with a microperforation (0.5%), which was treated with clipping. Histology showed adenoma in 85, intramucosal cancer in 83, submucosal invasive cancer. Of the 200 cases that had radical endoscopic resection, no tumor recurrence was found after treatment. During the study period, we abandoned ESD in only 2 of the 202 cases, because of severe fibrosis. Among the 35 cases with submucosal fibrosis, 13 cases were considered related to cancer invasion, and 22 cases were unrelated to cancer invasion. We completed en bloc resections for 26 lesions. Seven lesions were finally removed using the piecemeal EMR(Endoscopic Mucosal Resection) procedure because of a high degree of submucosal fibrosis. Therefore the rate of en bloc resection was 74.3%. The fibrosis of non-cancerous origin was caused by inflammation, biopsy, saline injection, and previous inadequate endoscopic treatment. We classified the endoscopic findings of ‘string-like’ or ‘rope-like’ as mild degree. ‘Band-like’ was classified as moderate degree, and ‘screen-like’ was severe degree fibrosis. Otherwise, a white or brown area and abnormal vessels were identified in the cases with submucosal cancer invasion. In the cases with slight submucosal cancer invasion, endoscopic examination showed a rough and string-like fibrosis accompanied by vessels. In cases with massive cancer invasion, endoscopic examination of the fibrous area showed a brown mass accompanied by irregular vessels, and was classified as severe degree. Lesions with fibrosis should be dissected carefully just above the muscularis propria. In cases with a high degree of fibrosis, ESD becomes more difficult because of the risk of severe complications. Conclusion: The tumor accompanied by mild to moderate fibrosis should become a standard indication for ESD. In contrast, ESD is not indicated for cases with a severe degree of fibrosis.