Endoscopic management of colorectal tumors less than 10 mm in size: Current status and future perspectives in Japan from a questionnaire survey

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.

Recent Advances in Gastrointestinal Cancer Endoscopic Diagnosis and Treatment: Focusing on Older Adults

Recent advances in endoscopic equipment have improved the diagnosis of gastrointestinal tumors. Image-enhanced endoscopy, including narrow-band imaging, blue light imaging, and linked color imaging, has unified magnifying observation classification methods and significantly improved the qualitative and quantitative diagnostic performance of gastrointestinal epithelial tumors. Endoscopic submucosal dissection (ESD), a minimally invasive treatment for early-stage gastrointestinal cancer, is widely used. The aging population in Japan has been gradually increasing. Despite this, ESD has shown good outcomes in older adults. However, long-term prognostic analyses should take into account the high mortality rate from other illnesses. Prognostic indicators such as the Charlson Comorbidity Index (CCI) and the Prognostic Nutrition Index (PNI) should be used to determine whether ESD should be performed. Even in cases of noncurative resection, follow-up without additional surgical resection is an option if there are other comorbidities that affect the prognosis.

Usefulness and Educational Benefit of a Virtual Scale Endoscope in Measuring Colorectal Polyp Size

INTRODUCTION

The virtual scale endoscope (VSE) is a newly introduced endoscope that helps endoscopists in measuring colorectal polyp size (CPS) during colonoscopy by displaying a virtual scale. This study aimed to determine the usefulness of the VSE for CPS measurement and the educational benefit of using VSE images to improve CPS estimation accuracy.

METHODS

This study included 42 colorectal polyps in 26 patients treated at Hiroshima University Hospital. In study 1, CPS measured using a VSE before endoscopic mucosal resection was compared with CPS measured on resected specimens, and the agreement between the two measurement methods was evaluated via Bland-Altman analysis. In study 2, 14 endoscopists (5 beginners, 5 intermediates, and 4 experts) took a pre-test to determine the size of 42 polyps. After the pre-test, a lecture on CPS measurement using VSE images was given. One month later, the endoscopists took a post-test to compare CPS accuracy before and after the lecture.

RESULTS

In study 1, Bland-Altman analysis revealed no fixed or proportional errors. The mean bias ±95% limits of agreement (±1.96 standard deviations) of the measurement error was -0.05 ± 0.21 mm, indicating that the agreement between two measurement methods was sufficient. In study 2, the accuracy of CPS measurement was significantly higher among beginners (59.5% vs. 26.7%, p < 0.01) and intermediates (65.2% vs. 44.3%, p < 0.05) in the post-test than in the pre-test.

CONCLUSION

The VSE accurately measures CPS before resection, and its images are useful teaching tools for beginner and intermediate endoscopists.

Bleeding Risk With Cold Snare Polypectomy of ≤10 mm Pedunculated Colon Polyps

OBJECTIVES

Pedunculated polyps (PPs) in the colon are usually resected with hot snare polypectomy to prevent immediate postpolypectomy bleeding (IPPB). This study aimed to evaluate the safety of CSP of <10 mm PPs.

MATERIALS AND METHODS

Patients undergoing colonoscopy from February 18, 2019, to April 24, 2020, and were found to have at least 1 ≤10 mm PP resected with CSP were included prospectively in a continuous quality improvement project to assess the risk of IPPB and delayed postpolypectomy bleeding. Polyp location, size, and pathology, as well as the method of resection, were recorded. In addition, we assessed the occurrence and severity of IPPB and the need for intervention.

RESULTS

We found 239 eligible polyps in 182 patients. The mean (SD) age was 58.8 (8.3) years, and 61% were males. IPPB occurred in 72 of 239 polyps, corresponding to a per-polyp bleeding percentage of 30.1% and in 65 of 182 patients, equating to a per-patient bleeding rate of 35.7%. We successfully treated bleeding by endoscopic hemostasis in 57%; the remaining 31 polyps (43%) did not require endoscopic intervention. There was no association between IPPB with age, gender, or use of aspirin or antithrombotic agents. In the bivariate model, polyp size and pathology were not associated with the risk of IPPB. Right-sided polyps were associated with a reduced risk of IPPB in the bivariate model by 61% (odds ratio=0.39; 95% confidence interval, 0.21-0.74; P =0.0057). In the multivariate model, choking the polyp base decreased the likelihood of IPPB by 97% (odds ratio=0.03; 95% confidence interval, 0.00-0.86; P =0.0459). There were no instances of delayed bleeding, perforation, or postpolypectomy syndrome.

CONCLUSIONS

CSP can be used for resection of ≤10 mm PPs. It is associated with a lower risk of immediate bleeding than the common perception among gastroenterologists.

Conditional inference tree models to perceive depth of invasion in T1 colorectal cancer

BACKGROUND AND AIM

Accurate diagnosis of invasion depth for T1 colorectal cancer is of critical importance as it decides optimal resection technique. Few reports have previously covered the effects of endoscopic morphology on depth assessment. We developed and validated a novel diagnostic algorithm that accurately predicts the depth of early colorectal cancer.

METHODS

We examined large pathological and endoscopic databases compiled between Jan 2015 and Dec 2018. Training and validation data cohorts were derived and real-world diagnostic performance of two conditional interference tree algorithms (Models 1 and 2) was evaluated against that of the Japan NBI-Expert Team (JNET) classification used by both expert and non-expert endoscopists.

RESULTS

Model 1 had higher sensitivity in deep submucosal invasion than that of JNET alone in both training (45.1% vs. 28.6%, p < 0.01) and validation sets (52.3% vs. 40.0%, p < 0.01). Model 2 demonstrated higher sensitivity than Model 1 (66.2% vs. 52.3%, p < 0.01) in excluding deeper invasion of suspected Tis/T1a lesions.

CONCLUSION

We discovered that machine-learning classifiers, including JNET and macroscopic features, provide the best non-invasive screen to exclude deeper invasion for suspected Tis/T1 lesions. Adding this algorithm improves depth diagnosis of T1 colorectal lesions for both expert and non-expert endoscopists.

Evaluation of cold snare polypectomy for small pedunculated (Ip) polyps with thin stalks: a prospective clinical feasibility study

BACKGROUND

Although the use of cold snare polypectomy (CSP) has spread rapidly, no prospective studies evaluating the safety of CSP for pedunculated (Ip) polyps have been carried out.

AIM

We performed this study to provide an accurate evaluation of the safety of CSP for Ip polyps.

METHODS

This is a prospective study (UMIN000035687). From January 2019 to February 2021, the safety of CSP for use on Ip polyps <10 mm with thin stalks was evaluated at our hospital. The primary outcome measure was the incidence of bleeding (delayed post-polypectomy bleeding (DPPB) and immediate bleeding).

RESULTS

During the study period, 89 consecutive patients (including 92 colonoscopies and 114 polyps) were prospectively enrolled. The en-bloc resection rate was 100%. The rate of DPPB after CSP was 0%, however, DPPB after conversion to HSP occurred in 1 case (33.3% (1/3)). The rate of immediate bleeding during CSP was 28.9% (33/114). Polyps with diameters ≥6 mm (OR (95% CI): 2.77 (1.041-7.376); p = .041) were extracted as independent risk factors for immediate bleeding during CSP for Ip polyps. In all, 104 (91.2%) polyps were low-grade adenomas, and the percentage of cases with negative pathological margins was 96.5% (110/114).

CONCLUSIONS

CSP for Ip polyps was safe and had good outcomes. We believe that Ip polyps could be included as an indication for CSP, and that CSP may become the next step in the 'cold revolution.' To confirm our results and verify CSP's inclusion in future guidelines, prospective, randomized studies are necessary.

Recurrence rate and lesions characteristics after cold snare polypectomy of high-grade dysplasia and T1 lesions: A multicenter analysis

BACKGROUND AND AIM

High-grade dysplasia (HGD) and T1 lesions are accidentally resected by cold snare polypectomy (CSP) and the characteristics, and follow-up of them has not been reported. In this study, we analyzed the histopathological findings and recurrence of them.

METHODS

This was a multicenter retrospective-cohort study. We collected HGD and T1 lesions of ≤ 10 mm resected by CSP among 15 520 patients receiving CSP from 2014 to 2019 at nine related institutions, and we extracted only cases receiving definite follow-up colonoscopy after CSP of HGD and T1 lesions. We analyzed these tumor's characteristics and therapeutic results such as R0 resection and local recurrence and risk factors of recurrence.

RESULTS

We collected 103 patients (0.63%) and extracted 80 lesions in 74 patients receiving follow-up colonoscopy for CSP scar. Mean age was 68.4 ± 12.0, and male rate was 68.9% (51/80). The mean tumor size (mm) was 6.6 ± 2.5, and the rate of polypoid morphology and rectum location was 77.5% and 25.0%. The rate of magnified observation was 53.8%. The rates of en bloc resection and R0 resection were 92.5% and 37.5%. The local recurrence rate was 6.3% (5/80, median follow-up period: 24.0 months). The recurrence developed within 3 months after CSP for four out of five recurrent cases. Comparing five recurrent lesions to 75 non-recurrent lesions, a positive horizontal margin was a significant risk factor (60.0% vs 10.7%, P < 0.001).

CONCLUSIONS

High-grade dysplasia and T1 resected by CSP were analyzed, and the local recurrence rate of them was substantially high.

A Comparative Study of Early Mucosal Healing Following Hot Polypectomy and Cold Polypectomy

BACKGROUND Cold polypectomy (CP) and hot polypectomy (HP) are both accepted methods for polypectomy. In recent years, the use of CP has increased for reasons of safety. However, there have been few investigations of conditions at follow-up early after resection. This prospective study from a single center aimed to compare colonic mucosal healing at 1 week following HP vs CP of benign colonic polyps <10 mm in diameter. MATERIAL AND METHODS Six patients with a total of 52 lesions under 10 mm in size were randomized to either the HP group (n=25) or CP group (n=27) using information in opaque envelopes. One week after endoscopic treatment, the site of treatment was evaluated using colonoscopy. We assessed the mean tumor size, ulcer diameter, exposed blood vessels, residual lesion, and complications. RESULTS Mean tumor size did not differ between the 2 groups (CP vs HP: 5.41 mm vs 5.68 mm). The CP group had a smaller ulcer base diameter (2.70 mm vs 4.84 mm; P<0.05) and fewer exposed blood vessels than the HP group (3.7% vs 36.0%; P<0.05). One residual lesion was found in the CP group. No patients experienced delayed perforation or post-polypectomy bleeding. CONCLUSIONS Our study findings showed that at 1-week follow-up, cold polypectomy resulted in improved colonic mucosal healing, with a smaller ulcer diameter and fewer blood vessels, when compared with hot polypectomy.

Factors associated with inaccurate size estimation of colorectal polyps: A multicenter cross-sectional study

BACKGROUND AND AIM

Accurate polyp size estimation is essential in deciding the therapeutic strategy of colorectal polyps and endoscopic surveillance intervals. However, many endoscopists frequently make incorrect size estimations without being aware of their errors. This cross-sectional study aimed to clarify the characteristics of endoscopists associated with inaccurate estimation.

METHODS

We previously conducted a web trial involving 261 endoscopists in 51 institutions in Japan to assess their ability to estimate polyp size. Participants answered questions about polyp size using visual estimates in a test involving images of 30 polyps. Here, we investigated the relationships between inaccurate size estimation and the backgrounds of participants. The rates of overestimation and underestimation of polyp size were also compared to clarify any trends in the answers of participants with low accuracy (< 50%).

RESULTS

Multivariable logistic regression analysis revealed that the number of colonoscopic procedures in the past year was the only factor associated with a low accuracy of polyp size estimation (odds ratio 0.750, 95% confidence interval 0.609-0.925; P = 0.007). Endoscopists with low accuracy had a greater tendency to overestimate polyp size (42.3% overestimation and 21.2% underestimation, P < 0.001) compared with other endoscopists (16.6% overestimation and 17.9% underestimation, P = 0.951).

CONCLUSIONS

Endoscopists with limited experience of colonoscopy in the past year were more likely to make frequent errors in size estimation. Furthermore, endoscopists making inaccurate size estimations had a propensity to overestimate polyp size.

Management of Less Than 10-mm-Sized Pedunculated (Ip) Polyps with Thin Stalk: Hot Snare Polypectomy Versus Cold Snare Polypectomy

BACKGROUND

Although the use of cold snare polypectomy (CSP) has spread rapidly, its safety for pedunculated (Ip) polyps remains controversial. In particular, the outcomes of hot snare polypectomy (HSP) and CSP for Ip polyps have not been previously compared.

AIMS

This study evaluated whether the rate of delayed postpolypectomy bleeding (DPPB) after CSP for Ip polyps was higher than that after HSP for Ip polyps and compared other outcomes (the rates of immediate bleeding and pathological margins) between the HSP and CSP procedures.

METHODS

A total of 5905 colorectal polyps in 4920 patients were resected at Omori Red Cross Hospital between October 2012 and June 2019. The polyps were divided into two groups: the HSP group (86 polyps, 64 patients) and the CSP group (102 polyps, 87 patients). The primary outcome measure was the incidence of DPPB. The secondary outcome measures were the incidences of immediate bleeding during the procedure and pathological margins of the resected specimen.

RESULTS

The rate of immediate bleeding during CSP was significantly higher than that for the HSP group [38.2% (39/102) versus 3.5% (3/86); p < 0.001]. However, the rate of DPPB was significantly higher in the HSP group than in the CSP group [4.7% (4/86) versus 0% (0/102); p < 0.001]. The rate of DPPB after CSP was 0%.

CONCLUSIONS

This is the first study to compare the outcomes of HSP and CSP for Ip polyps. CSP is safer than HSP for Ip polyps measuring < 10 mm in diameter.

Cold snare polypectomy for large sessile serrated lesions is safe but follow-up is needed: a single-centre retrospective study

BACKGROUND AND AIM

Cold snare polypectomy (CSP) is growing in popularity due to its safety and convenience. Its indication is benign tumours such as adenoma and sessile serrated lesions (SSLs) <10 mm in size. CSP for SSLs ≥10 mm in size has not been well examined. In this study, we aimed the feasibility of this treatment regarding therapeutic results and local recurrence.

METHODS

This was a single-centre retrospective cohort study. We reviewed SSLs with or without dysplasia of 10-20 mm that were resected by CSP from 2014 to 2020. All tumours were diagnosed endoscopically as SSLs without dysplasia before CSP with the help of magnifying narrow band imaging or blue laser imaging. We analysed the lesion characteristics, en bloc resection, histopathological diagnosis, adverse events and local recurrence. We analysed risk factors for recurrence, comparing recurrent lesions to non-recurrent lesions. We also compared risk factors for lesions 10-14 mm in size to those for lesions 15-20 mm in size.

RESULTS

We analysed 160 lesions in 100 patients (Mage  ± SD = 67.7 ± 10.1 years). The polyp size (M ± SD) was 11.8 ± 2.8 mm, and the en bloc resection rate was 60.0% (96 cases). The rates of massive perioperative haemorrhage, postoperative haemorrhage and perforation were 1.3%, 0% and 0%, respectively. Regarding histopathological diagnosis, two (1.2%) cases showed SSLs with high-grade dysplasia. The recurrence rate in 101 lesions with a median follow-up period of 18 months (interquartile range 12-24 months) was 5.0%. There were no significant risk factors such as tumour size, location, morphology and so on in terms of recurrence. All recurrent cases could be resected by repeat CSP. The recurrence rates of lesions 10-14 mm in size and 15-20 mm in size were 4.7% and 6.3%, respectively (p = 0.713).

CONCLUSION

CSP of SSLs ≥10 mm in size according to magnifying endoscopic diagnosis was safe and promising, but the rate of recurrence was slightly high, meaning that close follow-up is required.

Short educational video to improve the accuracy of colorectal polyp size estimation: Multicenter prospective study

BACKGROUND AND AIM

Accurate polyp size estimation is necessary for appropriate management of colorectal polyps. Polyp size is often determined by subjective visual estimation in clinical situations; however, it is inaccurate, especially for beginner endoscopists. We aimed to clarify the usefulness of our short training video, available on the Internet, for accurate polyp size estimation.

METHODS

We conducted a multicenter prospective controlled study in Japan. After completing a pretest composed of near and far images of 30 polyps, participants received the educational video lecture (<10 min long). The educational content included the knowledge of strategies based on polyp size and criteria for size estimation including the endoscopic equipment size and videos of polyps in vivo. After one month, the participants undertook a posttest. The primary outcome was a change in the accuracy of polyp size visual estimation between the pretest and posttest in beginners.

RESULTS

Participants including 111 beginners, 52 intermediates, and 97 experts from 51 institutions completed both tests. Accuracy of polyp size estimation in the beginners showed a significant increase after the video lecture [54.1% (51.3-57.0%) to 59.0% (56.5-61.5%), P = 0.003]. Multivariable logistic regression analysis showed that the category of beginners and a low score on pretest (P = 0.020 and <0.001, respectively) were the factors that contributed to an increase of ≥10% in the accuracy.

CONCLUSION

Our educational video led to an improvement in polyp size estimation in beginners. Furthermore, this video may be useful for non-beginners with insufficient polyp size estimation accuracy.

Chromoendoscopy: role in modern endoscopic imaging

Detection of early gastrointestinal tract malignancy can be challenging on white light endoscopy especially as lesions can be subtle and inconspicuous. With the advent of electronic chromoendoscopy technologies, lesions which have already been detected can be quickly and "conveniently" characterised. This review will discuss some of the indications and modern applications of chromoendoscopy in various conditions including Barrett's oesophagus, oesophageal squamous cell carcinoma, early gastric cancer, inflammatory bowel disease and neoplastic colonic lesions. In carefully selected situations, chromoendoscopy could still be a useful adjunct to white light endoscopy in day-to-day clinical practice.

Local recurrence and its risk factors after cold snare polypectomy of colorectal polyps

BACKGROUND

Local recurrence after cold snare polypectomy (CSP) of colorectal polyps has not been well analyzed. In this study, we analyzed the characteristics of local recurrence.

METHODS

We retrospectively reviewed consecutive lesions resected by CSP from 2014 to 2016 and lesions that were followed up at ≥ 10 months after CSP, were analyzed. Our indication for CSP was a benign tumor of < 15 mm in size. We analyzed local recurrence and its risk factors using multivariate analyses. In addition, we compared lesions of ≥ 10 mm and < 10 mm. Moreover, therapeutic methods for recurrence were analyzed.

RESULTS

Finally, we analyzed 554 cases out of 820 consecutive cases. The mean polyp size was 5.3 ± 2.8 mm and the en bloc resection and histopathological complete resection rates were 99.3% and 70.2%, respectively. The overall recurrence rate was 1.9% (mean follow-up period: 13.0 ± 4.0 months). Significant differences were observed between 11 recurrent lesions and 543 lesions without recurrence regarding polyp size (8.0 ± 3.7 mm vs. 5.2 ± 2.7 mm, p < 0.001), rate of sessile-serrated polyp (27.3% vs. 3.0%, p < 0.001), and histopathological positive margin (45.4% vs. 3.7%, p = 0.019). Multivariate analyses showed that a histopathological positive margin was the only significant risk factor for local recurrence (OR 16.600, 95% CI 3.707-74.331, p < 0.001). Regarding the comparison between 74 lesions of ≥ 10 mm and 480 lesions of < 10 mm, significant differences were observed in the en bloc resection rate (93.2% vs. 100%, p < 0.001), high-grade dysplasia rate (8.1% vs. 0.8%, p < 0.001), and histopathological complete resection rate (54.0% vs. 72.7%, p = 0.001). The recurrence rates of these two groups were 5.4% and 1.4%, respectively (p = 0.069). All recurrent cases could be resected with repeat CSP.

CONCLUSIONS

The local recurrence rate after CSP for lesions of < 10 mm was 1.4%. CSP was not recommended for lesions of ≥ 10 mm due to high rates of recurrence and malignancy.

Safety and efficacy of cold snare polypectomy for pedunculated (Ip) polyps measuring less than 10 mm in diameter

BACKGROUND

Although cold snare polypectomy (CSP) has spread rapidly, it still remains controversial whether CSP is safe for pedunculated (Ip) polyps.

PURPOSE

The aim of this study was to evaluate whether CSP for Ip polyps measuring less than 10 mm in diameter might be associated with an increased rate of delayed post-polypectomy bleeding (DPPB).

METHODS

A total of 1641 colorectal polyps in 634 patients were resected at Omori Red Cross Hospital between April 2018 and December 2018. The polyps were divided into two groups depending on the morphology: the Ip group (90 polyps), and the non-Ip group (1551 polyps).

RESULTS

Among the 1641 polyps, there was no case of DPPB, including in the Ip group. Immediate bleeding occurred in a total of 101 (6.2%) cases. Polyp location in the rectum (OR (95% CI), 3.61 (1.843-7.092); p < 0.001), polyp diameter ≥ 6 mm (OR (95% CI), 2.65 (1.702-4.132); p < 0.001), Ip morphology (OR (95% CI), 15.66 (9.262-26.49); p < 0.001), and treatment with antithrombotic agents (OR (95% CI), 2.18 (1.358-3.501); p = 0.0012) were identified as significant risk factors for immediate bleeding.

CONCLUSIONS

This is the first study conducted to examine the safety of CSP for Ip polyps measuring less than 10 mm in diameter. CSP can be performed with a high level of safety even for Ip polyps. Based on our findings, we believe that Ip polyps could be included as an indication for CSP. However, prospective, randomized studies are necessary to confirm our results.