Consensus molecular subtype transition during progression of colorectal cancer.

The consensus molecular subtype (CMS) classification divides colorectal cancer (CRC) into four distinct subtypes based on RNA expression profiles. The biological differences between CMSs are already present in CRC precursor lesions, but not all CMSs pose the same risk of malignant transformation. To fully understand the path to malignant transformation and to determine whether CMS is a fixed entity during progression, genomic and transcriptomic data from two regions of the same CRC lesion were compared: the precursor region and the carcinoma region. In total, 24 patients who underwent endoscopic removal of T1-2 CRC were included. Regions were subtyped for CMS and DNA mutation analysis was performed. Additionally, a set of 85 benign adenomas was CMS-subtyped. This analysis revealed that almost all benign adenomas were classified as CMS3 (91.8%). In contrast, CMS2 was the most prevalent subtype in precursor regions (66.7%), followed by CMS3 (29.2%). CMS4 was absent in precursor lesions and originated at the carcinoma stage. Importantly, CMS switching occurred in a substantial number of cases and almost all (six out of seven) CMS3 precursor regions showed a shift to a different subtype in the carcinoma part of the lesion, which in four cases was classified as CMS4. In conclusion, our data indicate that CMS3 is related to a more indolent type of precursor lesion that less likely progresses to CRC and when this occurs, it is often associated with a subtype change that includes the more aggressive mesenchymal CMS4. In contrast, an acquired CMS2 signature appeared to be rather fixed during early CRC development. Combined, our data show that subtype changes occur during progression and that CMS3 switching is related to changes in the genomic background through acquisition of a novel driver mutation (TP53) or selective expansion of a clone, but also occurred independently of such genetic changes. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Adverse events of endoscopic full-thickness resection: results from the German and Dutch nationwide colorectal FTRD registry.

BACKGROUND AND AIMS: Endoscopic full-thickness resection (eFTR) is emerging as a minimally invasive alternative to surgery for complex colorectal lesions. Previous studies have demonstrated favorable safety results; however, large studies representing a generalizable estimation of adverse events (AEs) are lacking. Our aim was to provide further insight in AEs after eFTR. METHODS: Data from all registered eFTR procedures in the German and Dutch colorectal full-thickness resection device registries between July 2015 and March 2021 were collected. Safety outcomes included immediate and late AEs. RESULTS: Of 1892 procedures, the overall AE rate was 11.3% (213/1892). No AE-related mortality occurred. Perforations occurred in 2.5% (47/1892) of all AEs, 57.4% (27/47) of immediate AEs, and 42.6% (20/47) of delayed AEs. Successful endoscopic closure was achieved in 29.8% of cases (13 immediate and 1 delayed), and antibiotic treatment was sufficient in 4.3% (2 delayed). The appendicitis rate for appendiceal lesions was 9.9% (13/131), and 46.2% (6/13) could be treated conservatively. The severe AE rate requiring surgery was 2.2% (42/1892), including delayed perforations in .9% (17/1892) and immediate perforations in .7% (13/1892). Delayed perforations occurred between days 1 and 10 (median, 2) after eFTR, and 58.8% (10/17) were located on the left side. Other severe AEs were appendicitis (.4%, 7/1892), luminal stenosis (.1%, 2/1892), delayed bleeding (.1%, 1/1892), pain after eFTR close to the dentate line (.1%, 1/1892), and grasper entrapment in the clip (.1%, 1/1892). CONCLUSIONS: Colorectal eFTR is a safe procedure with a low risk for severe AEs in everyday practice and without AE-related mortality. These results further support the position of eFTR as an established minimally invasive technique for complex colorectal lesions.

Deep Submucosal Invasion Is Not an Independent Risk Factor for Lymph Node Metastasis in T1 Colorectal Cancer: A Meta-Analysis.

BACKGROUND & AIMS: Deep submucosal invasion (DSI) is considered a key risk factor for lymph node metastasis (LNM) and important criterion to recommend surgery in T1 colorectal cancer. However, metastatic risk for DSI is shown to be low in the absence of other histologic risk factors. This meta-analysis determines the independent risk of DSI for LNM. METHODS: Suitable studies were included to establish LNM risk for DSI in univariable analysis. To assess DSI as independent risk factor, studies were eligible if risk factors (eg, DSI, poor differentiation, lymphovascular invasion, and high-grade tumor budding) were simultaneously included in multivariable analysis or LNM rate of DSI was described in absence of poor differentiation, lymphovascular invasion, and high-grade tumor budding. Odds ratios (OR) and 95% CIs were calculated. RESULTS: Sixty-seven studies (21,238 patients) were included. Overall LNM rate was 11.2% and significantly higher for DSI-positive cancers (OR, 2.58; 95% CI, 2.10-3.18). Eight studies (3621 patients) were included in multivariable meta-analysis and did not weigh DSI as a significant predictor for LNM (OR, 1.73; 95% CI, 0.96-3.12). As opposed to a significant association between LNM and poor differentiation (OR, 2.14; 95% CI, 1.39-3.28), high-grade tumor budding (OR, 2.83; 95% CI, 2.06-3.88), and lymphovascular invasion (OR, 3.16; 95% CI, 1.88-5.33). Eight studies (1146 patients) analyzed DSI as solitary risk factor; absolute risk of LNM was 2.6% and pooled incidence rate was 2.83 (95% CI, 1.66-4.78). CONCLUSIONS: DSI is not a strong independent predictor for LNM and should be reconsidered as a sole indicator for oncologic surgery. The expanding armamentarium for local excision as first-line treatment prompts serious consideration in amenable cases to tailor T1 colorectal cancer management.

Setting up a regional expert panel for complex colorectal polyps.

BACKGROUND AND AIMS: Advanced endoscopic resection techniques for complex colorectal polyps have evolved significantly over the past decade, leading to a management shift from surgical to endoscopic resection as the preferred treatment. However, in practice, interhospital consultation and appropriate referral management remain challenging, leading to unnecessary surgical resections. To support regional care for patients with complex colorectal polyps, facilitate peer consultations, and lower thresholds for referrals, an expert panel consultation platform was initiated in the northwestern region of the Netherlands. METHODS: We initiated a regional expert panel in the northwestern region of the Netherlands for patients with complex colorectal polyps and studied the implementation, adaption, and clinical impact. All panel consultations between June 2019 and May 2021 were retrospectively analyzed, and user satisfaction among panel members was evaluated. RESULTS: Eighty-eight patients with complex colorectal polyps from 11 of 15 participating centers (73.3%) were discussed in our panel. The most common reason for panel consultation was suspicion of invasive cancer in 36.4% (n = 32). After panel consultation, 43.2% of the consulting endoscopists (n = 38) changed their initial treatment strategy, and in 63.6% (n = 56) patients were referred to another endoscopy center. Of 26 cases submitted with a primary proposal for surgical treatment, surgery was avoided in 7 (26.9%). User satisfaction was rated high in most participating centers (91.7%). CONCLUSIONS: Our study shows that implementation of and consultation with a regional expert panel can be a valuable tool for endoscopists to guide and optimize treatment of complex colorectal polyps and facilitate interhospital referrals in a regional network.

Novel classification for adverse events in GI endoscopy: the AGREE classification.

BACKGROUND AND AIMS: Standardized registration and evaluation of adverse events (AEs) are essential to assess the safety of endoscopic procedures. We propose a novel classification system, named adverse events in GI endoscopy (AGREE), adapted from a widely accepted surgical tool. METHODS: The Clavien-Dindo classification for surgical AEs was adapted for endoscopy. To validate the novel classification, we assessed if the severity of AEs, as perceived by 10 endoscopists, 10 endoscopy nurses, and 10 patients, corresponded with the severity grading used in the AGREE classification in 10 pairwise comparisons. We additionally assessed the correlation between the AGREE classification and the American Society for Gastrointestinal Endoscopy (ASGE) classification. The acceptability of the AGREE classification was evaluated through an international questionnaire. RESULTS: The perception of endoscopists, endoscopy nurses, and patients corresponded with the severity grading of the AGREE classification in 80% of cases (238/299). The AGREE classification significantly correlated with the ASGE classification (ρ = .760). Fifty-seven of 84 experts (68%) completed a questionnaire regarding the acceptability of the AGREE classification. The experts consulted considered the AGREE classification as simple (86%), reproducible (98%), logical (98%), and useful (96%). Most case presentations (84%) were correctly graded according to the AGREE classification. CONCLUSIONS: The AGREE classification provides a standardized and reproducible approach to the assessment of AEs in diagnostic and therapeutic GI endoscopy. Broad implementation of the AGREE classification may facilitate the evaluation of AEs across different endoscopists, disciplines, endoscopy services, and regions. This standardization of AE reporting will support improved quality assurance in GI endoscopy.

Endoscopic full-thickness resection of T1 colorectal cancers: a retrospective analysis from a multicenter Dutch eFTR registry.

BACKGROUND: Complete endoscopic resection and accurate histological evaluation for T1 colorectal cancer (CRC) are critical in determining subsequent treatment. Endoscopic full-thickness resection (eFTR) is a new treatment option for T1 CRC < 2 cm. We aimed to report clinical outcomes and short-term results. METHODS: Consecutive eFTR procedures for T1 CRC, prospectively recorded in our national registry between November 2015 and April 2020, were retrospectively analyzed. Primary outcomes were technical success and R0 resection. Secondary outcomes were histological risk assessment, curative resection, adverse events, and short-term outcomes. RESULTS: We included 330 procedures: 132 primary resections and 198 secondary scar resections after incomplete T1 CRC resection. Overall technical success, R0 resection, and curative resection rates were 87.0 % (95 % confidence interval [CI] 82.7 %-90.3 %), 85.6 % (95 %CI 81.2 %-89.2 %), and 60.3 % (95 %CI 54.7 %-65.7 %). Curative resection rate was 23.7 % (95 %CI 15.9 %-33.6 %) for primary resection of T1 CRC and 60.8 % (95 %CI 50.4 %-70.4 %) after excluding deep submucosal invasion as a risk factor. Risk stratification was possible in 99.3 %. The severe adverse event rate was 2.2 %. Additional oncological surgery was performed in 49/320 (15.3 %), with residual cancer in 11/49 (22.4 %). Endoscopic follow-up was available in 200/242 (82.6 %), with a median of 4 months and residual cancer in 1 (0.5 %) following an incomplete resection. CONCLUSIONS: eFTR is relatively safe and effective for resection of small T1 CRC, both as primary and secondary treatment. eFTR can expand endoscopic treatment options for T1 CRC and could help to reduce surgical overtreatment. Future studies should focus on long-term outcomes.

Hybrid endoscopic mucosal resection and full-thickness resection for large colonic polyps harboring a small focus of invasive cancer: a case series.

Endoscopic treatment of large laterally spreading tumors (LSTs) with a focus of submucosally invasive colorectal cancer (T1 CRC) can be challenging. We evaluated outcomes of a hybrid resection technique using piecemeal endoscopic mucosal resection (pEMR) and endoscopic full-thickness resection (eFTR) in patients with large colonic LSTs containing suspected T1 CRC. Six hybrid pEMR-eFTR procedures for T1 CRCs were registered in a nationwide eFTR registry between July 2015 and December 2019. In all cases, the invasive part of the lesion was successfully isolated with eFTR; with eFTR, histologically complete resection of the invasive part was achieved in 5 /6 patients (83.3 %). No adverse events occurred during or after the procedure. The median follow-up time was 10 months (range 6-27), with all patients having undergone ≥ 1 surveillance colonoscopy. One patient had a small adenomatous recurrence, which was removed endoscopically. In conclusion, hybrid pEMR-eFTR is a promising noninvasive treatment modality that seems feasible for a selected group of patients with large LSTs containing a small focus of T1 CRC.

[Experiences with endoscopic full-thickness resection of complex colorectal lesions]. / Ervaringen met endoscopische 'full-thickness'-resectie van colorectale afwijkingen.

Endoscopic full-thickness resection (eFTR) is a minimally invasive resection technique that allows definite diagnosis and treatment for complex colorectal lesions unsuitable to conventional endoscopic resection. With the advantage of enabling a transmural resection, eFTR offers an alternative to radical surgery. Since the introduction of the full-thickness resection device in 2015, a nationwide prospective registry of consecutive eFTR procedures for all indications was initiated in the Netherlands, aiming to monitor patient outcomes and increase further knowledge on its clinical applicability and safety. Data show that eFTR is clinically feasible and relatively safe for complex colorectal lesions. Furthermore, eFTR is gaining interest as a diagnostic and therapeutic treatment option for T1 colorectal cancer.

Endoscopic full-thickness resection (eFTR) of colorectal lesions: results from the Dutch colorectal eFTR registry.

BACKGROUND: Endoscopic full-thickness resection (eFTR) is a minimally invasive resection technique that allows definite diagnosis and treatment for complex colorectal lesions ≤ 30 mm unsuitable for conventional endoscopic resection. This study reports clinical outcomes from the Dutch colorectal eFTR registry. METHODS: Consecutive patients undergoing eFTR in 20 hospitals were prospectively included. The primary outcome was technical success, defined as macroscopic complete en bloc resection. Secondary outcomes were: clinical success, defined as tumor-free resection margins (R0 resection); full-thickness resection rate; and adverse events. RESULTS : Between July 2015 and October 2018, 367 procedures were included. Indications were difficult polyps (non-lifting sign and/or difficult location; n = 133), primary resection of suspected T1 colorectal cancer (CRC; n = 71), re-resection after incomplete resection of T1 CRC (n = 150), and subepithelial tumors (n = 13). Technical success was achieved in 308 procedures (83.9 %). In 21 procedures (5.7 %), eFTR was not performed because the lesion could not be reached or retracted into the cap. In the remaining 346 procedures, R0 resection was achieved in 285 (82.4 %) and full-thickness resection in 288 (83.2 %). The median diameter of resected specimens was 23 mm. Overall adverse event rate was 9.3 % (n = 34/367): 10 patients (2.7 %) required emergency surgery for five delayed and two immediate perforations and three cases of appendicitis. CONCLUSION : eFTR is an effective and relatively safe en bloc resection technique for complex colorectal lesions with the potential to avoid surgery. Further studies assessing the role of eFTR in early CRC treatment with long-term outcomes are needed.

[Unnecessary surgery for benign colorectal polyps]. / Te veel operaties voor benigne darmpoliepen.

Colorectal cancer usually starts as a benign polyp. Endoscopic removal of these polyps reduces the risk of death from colorectal cancer. Some of the colorectal polyps are seen as 'too complex for endoscopic removal' and these polyps can be surgically resected. However, surgical resection is associated with higher morbidity and mortality. We have various advanced endoscopic techniques at our disposal for removing benign polyps these days, even if they are complex. The number of surgical resections of benign polyps is nevertheless increasing in the Netherlands, partly as a result of the introduction of population screening for colorectal cancer. Only a small proportion of patients with complex polyps is referred to a centre of expertise to undergo advanced endoscopic resection. We believe that regional multidisciplinary expert panels can improve the quality of care for patients with complex polyps and reduce the number of unnecessary surgical resections.