Factors associated with non-lifting of colorectal mucosal lesions

Endoscopic submucosal dissection (ESD) is an effective treatment for colorectal tumors. However, lesions that cannot be lifted after submucosal injection are not indication for ESD. This is because the procedure is difficult, and the lesions are often considered as tumor invasion or submucosal fibrosis. The aims of this study are to evaluate the efficacy and safety of ESD for non-lifting lesions and to analyze the causes of non-lifting phenomenon.This retrospective study included 29 patients with non-lifting colon lesions resected by ESD from February 2018 to September 2021. Cases were observed for demographics, endoscopic findings, treatment outcomes, adverse events and endoscopic follow-up. We studied the pathological features of lesions to explore the reasons for non-lifting.Among 29 cases of non-lifting lesions, 20 lesions (69.0%) were 30 mm in diameter or larger. Most of lesions (96.6%) were non-lifting in center, and only one lesions (3.4%) had non-lifting of one side. The en bloc and curative resection rates of ESD were 100 and 86.2%, respectively. There was one (3.4%) delayed bleeding, no perforations and other complications. No tumor recurrence occurred during the follow-up period. For pathological features, 16 (55.2%) non-lifting lesions had submucosal fibrosis and only 4 cases (13.8%) had deep submucosal invasion. There were 9 cases (31.0%) of non-lifting lesions due to musculo-fibrous of muscularis propria anomaly (MMPA).MMPA is another reason for non-lifting signs besides invasive carcinomas and submucosal fibrosis. ESD should be considered in patients with large non-lifting adenoma instead of surgery.