In conclusion, EMR is useful for treating [less than or equal to]20 mm colorectal LSTs with regard to curative resection and procedure time, and LSTs with an adenomatous pit pattern, high-grade dysplasia histology, or adenocarcinoma histology are significant independent risk factors for piecemeal resection after EMR for colorectal LSTs.
En bloc and piecemeal resections were defined as resection with a single piece and resection with multiple pieces, respectively.
All the ESD cases were also categorized as en bloc or piecemeal resection. Moreover, we analyzed the factors associated with the piecemeal resection of CRNs.
In case of piecemeal resection or a histologically positive lateral resection margin, the first surveillance endoscopy was done within 6 months after endoscopic treatment.
In cases of piecemeal resection, the greatest dimension of the assembled gross specimen was considered as the size of the lesion if all of resected tumors could be spread and fixed onto a hard Styrofoam.
If the pieces of the specimens could not be accurately assembled after the piecemeal resection, it was considered as histologic incomplete resection.
Risk factors for piecemeal resection were analyzed using univariate method.
In this study, we found that the en bloc resection rate of colorectal ESD was 85.7%, and that the application of hybrid ESD and presence of submucosal fibrosis were independently associated with piecemeal resection. In our clinical practice, hybrid ESD was performed to remove lesions quickly, especially for the safety of patients with intraprocedural problems such as bleeding or higher perforation risk, and to complete the resection of lesions that were hard to remove with standard ESD due to the difficult location or submucosal fibrosis.
As expected, piecemeal resection, despite the application of ESD, led to a significantly higher recurrence rate, as compared to that with en bloc ESD cases (5.6% vs.
Of 4 cases of piecemeal ESD, 3 exhibited local recurrence at the first follow-up endoscopy session after ESD; hence, as mentioned in the current postpolypectomy surveillance guidelines, a follow-up interval of 3-6 months after ESD may be essential in cases of piecemeal resection (25-27).
First, as our data were based on a retrospective, single center experience, selection bias related to surveillance and the decision of rescue treatment after piecemeal resection might have influenced the recurrence rate of the piecemeal ESD cases.