Novel endoscopic ultrasonography classification for assured vertical resection margin (≥500 μm) in colorectal endoscopic submucosal dissection

Abstract

Background and Aim The risk of local recurrence might be low in pT1 colorectal carcinoma with a tumor vertical margin (VM) ≥500 μm. We investigated the relationship between endoscopic ultrasonography (EUS) findings and VM in cases with colorectal endoscopic submucosal dissection (ESD) categorized as Type 2B according to the Japan NBI Expert Team (JNET) classification. Methods We analyzed 179 JNET Type 2B colorectal tumors resected by ESD at Hiroshima University Hospital from January 2010 to May 2021. The distance from the tumor invasive front to the muscle layer on EUS was defined as the tumor‐free distance (EUS‐TFD) and classified as Type I (EUS‐TFD ≥1 mm) and II (<1 mm). We investigated the relationship between EUS‐TFD and VM and analyzed the predictive factors for VM ≥500 μm. Results EUS‐TFD Type I was diagnosed in 133 (74.3%) lesions: VM ≥500 μm (114, 85.7%); VM <500 μm (19, 14.3%); and VM positive (VM1) (0, 0%). Type II was diagnosed in 46 (25.7%) lesions: VM ≥500 μm (14, 30.5%); VM <500 μm (22, 47.8%); and VM1 (10, 21.7%). In the EUS‐TFD Type I cases, 84.5% and 87.8% were protruded and superficial types; whereas for Type II cases, these were 38.9% and 25%, respectively. EUS‐TFD classification (Type I), scope operability (good), submucosal invasion depth (<2000 μm), histology at the deepest invasive portion (favorable), and degree of fibrosis (F0/F1) were significant predictors of VM ≥500 μm. Conclusions In JNET Type 2B lesions, EUS‐TFD classification is a novel diagnostic indicator to predict VM ≥500 μm in ESD preoperatively.

Vertical margin distance in T1 colorectal carcinoma resected by endoscopic submucosal dissection affects prognosis after additional surgery

“…Preoperative EUS is useful for predicting the VM distance [12,42]. We de ned the distance from the tumor invasive front to the muscle layer on EUS as being tumor-free and found that classifying tumor-free distance as < 1 or ≥ 1 mm was useful for preoperative prediction of VM distance ≥ 500 µm [42]. In the near future, preoperative EUS will become increasingly important for evaluating whether pT1b CRC can be treated by ESD as a total excisional biopsy.…”

Endoscopic submucosal dissection and JNET classification for colorectal neoplasia: A North American academic center experience

“…Development of new techniques for predicting lesion depth, through endoscopic ultrasonography for instance, is ongoing and eagerly awaited. 30 The development of Western training programs with a focus on optical diagnosis, lesion selection, ESD technique, and addressing logistical barriers to ESD will enable more widespread adoption of the ESD technique in North America.…”

“…As more case series are reported, conducting meta‐analyses that describe regional outcomes and further evaluate the application of the JNET classification will be valuable in advancing our understanding and optimizing the management of colorectal lesions. Development of new techniques for predicting lesion depth, through endoscopic ultrasonography for instance, is ongoing and eagerly awaited 30 . The development of Western training programs with a focus on optical diagnosis, lesion selection, ESD technique, and addressing logistical barriers to ESD will enable more widespread adoption of the ESD technique in North America.…”

Diagnostic and therapeutic strategies for colorectal tumor with positive muscle‐retracting sign

“…Endoscopic ultrasonography (EUS) is a useful modality that allows objective visualization of the colorectal wall; it is useful for the diagnosis of tumor invasion depth and dissectible submucosal space between the tumor-invasive front and muscle layer. [18][19][20][21][22][23] The pocket-creation method (PCM) is an ESD strategy that facilitates the maintenance of a thick submucosal layer by preventing leakage of the injected solution and providing good submucosal traction and scope operability. [24][25][26][27][28] In this study, we aimed to evaluate the effectiveness of diagnostic strategies for MR sign of colorectal tumors via EUS;in addition,we aimed to perform ESD with PCM.…”

“…Endoscopic ultrasonography (EUS) is a useful modality that allows objective visualization of the colorectal wall; it is useful for the diagnosis of tumor invasion depth and dissectible submucosal space between the tumor‐invasive front and muscle layer. 18 , 19 , 20 , 21 , 22 , 23…”