Standardization of endoscopic resection for colorectal tumors larger than 10 mm in diameter

Clinical usefulness of hybrid endoscopic submucosal dissection for T1b colorectal carcinomas ≤20 mm to ensure adequate vertical margins

Objective

To evaluate endoscopic resection strategies for cT1b colorectal carcinomas (CRCs) ≤20 mm to determine strategies that enable adequate vertical margins (VMs).

Methods

We enrolled 128 consecutive patients with cT1b colorectal carcinomas ≤20 mm resected by endoscopic mucosal resection or hybrid endoscopic submucosal dissection (ESD). Tumor lifting conditions after submucosal injection were classified into type A (lifting, soft dome-like), type B (lifting, hard trapezoid-like), and non-lifting (positive non-lifting sign). Predictors of positive VMs (VM 1) and adequate VMs were identified.

Results

All non-lifting tumors were resected by hybrid ESD and VMs were ≥500 µm. Vertical margin 1 tumors were only found in the endoscopic mucosal resection group, in which, the proportion of type B tumors with VM 1 was significantly higher than that of tumors with negative VMs (p < 0.01). Type A tumors showed no significant between-group differences. Among type B tumors, the proportion of VMs ≥500 µm was significantly higher (p < 0.01) and the VM distance was significantly longer (p < 0.01) in the hybrid ESD group than in the endoscopic mucosal resection group.

Conclusions

Hybrid ESD can be selected for type B tumors to ensure adequate VMs.

A case of colon cancer implanted on endoscopic resection ulcer certified by cancer genomic testing

A 90 year-old man underwent endoscopic mucosal resection for lesions in the descending and sigmoid colons as well as endoscopic submucosal dissection (ESD) for a lesion in the rectal peritoneal reflection (Ra) 1 month before undergoing laparoscopic resection and D3 dissection for advanced cancer in the descending colon. One year later, he underwent a surveillance colonoscopy, and advanced colorectal cancer was detected on the ESD scar. The history suggested that this newly detected recurrent colorectal neoplasm on the ESD scar may have originated from cancer cells derived from the descending colon cancer that were implanted in the ESD ulcer, thereby initiating a new colorectal neoplasm. Cancer genomic testing further indicated that three of the four pathogenic variants detected in the recurrent colorectal neoplasm were consistent with pathogenic variants of descending colon cancer. This finding strongly supports our contention that cancer cells derived from the descending colon cancer were implanted in the post-ESD ulcer of the rectal Ra and proliferated, forming the recurrent colorectal neoplasm. This case report highlights the potential for tumor cell implantation on endoscopic resection ulcers and the utility of cancer genomic testing in validating this phenomenon.

Clinical outcomes of endoscopic resection for colorectal laterally spreading tumors with advanced histology

BACKGROUND

Colorectal laterally spreading tumors (LSTs) are large, flat neoplasms that are usually treated using different endoscopic techniques based on their morphology, size, and histology. The aim of this study was to evaluate the clinical outcomes of LSTs with advanced histology treated by endoscopic resection.

METHODS

A total of 246 LSTs with advanced histology [i.e., high-grade dysplasia (HGD) and adenocarcinoma (AC)] treated by endoscopic resection [i.e., endoscopic mucosal resection (EMR), EMR-precutting (EMR-P), and endoscopic submucosal dissection (ESD)] were enrolled. Clinicopathological characteristics were collected by review of patient's medical records.

RESULTS

The en bloc resection and R0 resection rates were 75.6% and 85.0%, respectively. The bleeding and perforation rates were 10.2% and 2.4%, respectively. The frequency of cancerous pit pattern and bleeding was significantly higher in LSTs with AC than in LSTs with HGD. The R0 resection rate in LSTs with HGD was significantly higher than that in LSTs with AC. The frequency of cancerous pit patterns in LST cases with submucosal AC was significantly higher than those with intramucosal AC. The mean size of the LSTs was significantly larger in ESD group than in EMR or EMR-P groups. The frequencies of nodular mixed subtype, cancerous pit patterns, and en bloc resection rates were significantly higher in the ESD group than in the EMR or EMR-P groups. However, the frequency of perforation was significantly higher in EMR-P group than in EMR or ESD groups.

CONCLUSIONS

These results indicate that ESD is a more acceptable treatment approach for resection of colorectal LSTs of larger size, with nodular mixed subtype, having a cancerous pit pattern or AC, using either en bloc or curative resection methods, compared to EMR or EMR-P procedures.

Characteristics of Patients with Colonic Polyps Requiring Segmental Resection

BACKGROUND

It is unclear if the availability of new techniques for removal of large colonic polyps has affected the use of segmental colon resection. We sought to evaluate the characteristics of polyps undergoing surgical resection, including involvement of therapeutic gastroenterologists (TG).

METHODS

484 patients had a colonic resection; 165 (34%) were identified from the pathology database with polyp, adenoma, or mass in the clinical history field; these charts were reviewed.

RESULTS

128 patients (mean age 68 yrs, 72% male) were included. The mean polyp size was 2.9 cm (0.4 cm-12.0 cm). Adenocarcinoma was diagnosed in 50 (39.1%). 97 (75.8%) patients had a polyp that was felt to be unresectable by EMR, and 31 (24.2%) underwent successful EMR followed by surgery for adenocarcinoma (n = 29). The indication for surgery in those with unresectable polyps was variable and was not clearly documented in 51 (52.6%); only 17 of these patients (17.5%) had a TG involved.

CONCLUSION

A high proportion of polyps managed by segmental resection did not contain adenocarcinoma. This data suggests that even in a tertiary care center where advanced endoscopic techniques are easily available, they are not always utilized. Educational endeavors to ensure that ideal pathways of intervention are utilized require implementation.