Endoscopic Mucosal Resection for Colorectal Polyps
Endoscopic Mucosal Resection for Colorectal Polyps
Background and Aim: Adequate mucosal elevation by submucosal injection is important for definitive en bloc resection and prevention of perforation during endoscopic mucosal resection (EMR). The objective of this study is to determine the efficacy of 0.13% hyaluronic acid (HA) solution for high and sustained mucosal elevation during colorectal EMR.
Methods: The study was a prospective randomized controlled trial; a total of 196 patients with colon polyps of < 20 mm diameter were enrolled and randomized in a 1:1 ratio to undergo EMR using either 0.13% HA or normal saline (NS). The primary outcome of the study was histopathologically confirmed complete resection. The secondary outcomes such as maintenance of high mucosal elevation and development of complications were also evaluated. Moreover, the relationship between complete resection and the experience of the endoscopist (veteran vs less experienced) was analyzed.
Results: Compete resection was achieved in 74 of 93 polyps (79.5%) in the 0.13% HA group and 63 of 96 polyps (65.6%) in the NS group (P < 0.05). High mucosal elevation was maintained in 83.9% of procedures in the 0.13% HA group and 54.1% in the NS group (P < 0.01). The frequency of complete resection achieved by less-experienced endoscopists was higher in the 0.13% HA group (79.3%) than in the NS group (62.1%; P < 0.05).
Conclusions: Endoscopic mucosal resection using 0.13% HA to colon polyps of less than 20 mm diameter is more effective than NS for complete resection and maintenance of mucosal elevation.
Endoscopic mucosal resection (EMR) is considered the standard procedure for colorectal polyps. Rosenberg first described the saline injection-assisted method and identified it as a safety factor for removing rectal and sigmoid polyps, and this technique was reintroduced by Tada et al. in 1984. Most adenoma and intramucosal cancers can be resected by EMR; however, tumors of > 20 mm diameter are considered difficult candidates for en bloc resection. Endoscopic submucosal dissection (ESD) can remove large-sized lesions of early colorectal cancer, but it can be a time-consuming procedure and carries a higher risk of perforation than EMR. Thus, it is important to improve the technical feasibility of EMR for en bloc and extended resections. Moreover, most colorectal polyps removed by EMR are < 20 mm diameter in size. The rate of en bloc resection and compete resection of EMR to these lesions is known to be good, but not perfect, especially for less experienced endoscopists. In EMR, submucosal fluid injection is necessary to obtain high mucosal elevation, which facilitates removal of the lesion. Low mucosal elevation makes snaring difficult; moreover, electrocautery damage of the muscularis propria due to low mucosal elevation may cause delayed perforation. We previously reported that mucosal elevation with normal saline (NS) dissipated within 2 min of injection, which is the length of time necessary for most endoscopists to perform EMR. Many additional solutions have been used to achieve sustained mucosal elevation, definitive en bloc resection, and prevention of perforation in EMR. Hypertonic saline, glycerol, dextrose, fibrinogen, succinylated gelatin and autologous blood induce improvement of complete resection and mucosal elevation that lasts longer than that induced by NS. Hyaluronic acid (HA) has been shown to create higher and sustainable mucosal elevation than NS. Yamamoto et al. first reported the efficacy of HA in novel endoscopic resection of a large colorectal polyp, and this was subsequently termed ESD. Injection of HA reportedly causes less tissue damage than hypertonic solutions such as dextrose, which are known to cause damage at local injections sites. However, the viscosity of high concentrations of HA can make snaring difficult in our previous study. It is important to dilute HA because HA is more expensive than NS. Thus, we demonstrated that an HA concentration as low as 0.13% was effective for sustained mucosal elevation in resected porcine colon and in living minipig colon. However, there is no clinical experience with EMR using 0.13% HA, and there have been no randomized controlled trials showing the efficacy of HA compared to NS in colorectal EMR. In the current study, we conducted a randomized controlled trial comparing the efficacy of 0.13% HA and NS in EMR to colorectal tumor of < 20 mm diameter.
Abstract and Introduction
Abstract
Background and Aim: Adequate mucosal elevation by submucosal injection is important for definitive en bloc resection and prevention of perforation during endoscopic mucosal resection (EMR). The objective of this study is to determine the efficacy of 0.13% hyaluronic acid (HA) solution for high and sustained mucosal elevation during colorectal EMR.
Methods: The study was a prospective randomized controlled trial; a total of 196 patients with colon polyps of < 20 mm diameter were enrolled and randomized in a 1:1 ratio to undergo EMR using either 0.13% HA or normal saline (NS). The primary outcome of the study was histopathologically confirmed complete resection. The secondary outcomes such as maintenance of high mucosal elevation and development of complications were also evaluated. Moreover, the relationship between complete resection and the experience of the endoscopist (veteran vs less experienced) was analyzed.
Results: Compete resection was achieved in 74 of 93 polyps (79.5%) in the 0.13% HA group and 63 of 96 polyps (65.6%) in the NS group (P < 0.05). High mucosal elevation was maintained in 83.9% of procedures in the 0.13% HA group and 54.1% in the NS group (P < 0.01). The frequency of complete resection achieved by less-experienced endoscopists was higher in the 0.13% HA group (79.3%) than in the NS group (62.1%; P < 0.05).
Conclusions: Endoscopic mucosal resection using 0.13% HA to colon polyps of less than 20 mm diameter is more effective than NS for complete resection and maintenance of mucosal elevation.
Introduction
Endoscopic mucosal resection (EMR) is considered the standard procedure for colorectal polyps. Rosenberg first described the saline injection-assisted method and identified it as a safety factor for removing rectal and sigmoid polyps, and this technique was reintroduced by Tada et al. in 1984. Most adenoma and intramucosal cancers can be resected by EMR; however, tumors of > 20 mm diameter are considered difficult candidates for en bloc resection. Endoscopic submucosal dissection (ESD) can remove large-sized lesions of early colorectal cancer, but it can be a time-consuming procedure and carries a higher risk of perforation than EMR. Thus, it is important to improve the technical feasibility of EMR for en bloc and extended resections. Moreover, most colorectal polyps removed by EMR are < 20 mm diameter in size. The rate of en bloc resection and compete resection of EMR to these lesions is known to be good, but not perfect, especially for less experienced endoscopists. In EMR, submucosal fluid injection is necessary to obtain high mucosal elevation, which facilitates removal of the lesion. Low mucosal elevation makes snaring difficult; moreover, electrocautery damage of the muscularis propria due to low mucosal elevation may cause delayed perforation. We previously reported that mucosal elevation with normal saline (NS) dissipated within 2 min of injection, which is the length of time necessary for most endoscopists to perform EMR. Many additional solutions have been used to achieve sustained mucosal elevation, definitive en bloc resection, and prevention of perforation in EMR. Hypertonic saline, glycerol, dextrose, fibrinogen, succinylated gelatin and autologous blood induce improvement of complete resection and mucosal elevation that lasts longer than that induced by NS. Hyaluronic acid (HA) has been shown to create higher and sustainable mucosal elevation than NS. Yamamoto et al. first reported the efficacy of HA in novel endoscopic resection of a large colorectal polyp, and this was subsequently termed ESD. Injection of HA reportedly causes less tissue damage than hypertonic solutions such as dextrose, which are known to cause damage at local injections sites. However, the viscosity of high concentrations of HA can make snaring difficult in our previous study. It is important to dilute HA because HA is more expensive than NS. Thus, we demonstrated that an HA concentration as low as 0.13% was effective for sustained mucosal elevation in resected porcine colon and in living minipig colon. However, there is no clinical experience with EMR using 0.13% HA, and there have been no randomized controlled trials showing the efficacy of HA compared to NS in colorectal EMR. In the current study, we conducted a randomized controlled trial comparing the efficacy of 0.13% HA and NS in EMR to colorectal tumor of < 20 mm diameter.
Source...