Towards safer and appropriate application of endoscopic submucosal dissection for T1 colorectal carcinoma as total excisional biopsy: future perspectives

Treatment Decision for Locally Resected T1 Colorectal Carcinoma-Verification of the Japanese Guideline Criteria for Additional Surgery Based on Long-Term Clinical Outcomes

INTRODUCTION

To verify the value of the pathological criteria for additional treatment in locally resected pT1 colorectal carcinoma (CRC) which have been used in the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines since 2009.

METHODS

We enrolled 4,667 patients with pT1 CRC treated at 27 institutions between July 2009 and December 2016 (1,257 patients with local resection alone [group A], 1,512 patients with additional surgery after local resection [group B], and 1,898 patients with surgery alone [group C]). All 5 factors of the JSCCR guidelines (submucosal resection margin, tumor histologic grade, submucosal invasion depth, lymphovascular invasion, and tumor budding) for lymph node metastasis (LNM) had been diagnosed prospectively.

RESULTS

Any of the risk factors were present in 3,751 patients. The LNM incidence was 10.4% (95% confidence interval 9.4-11.5) in group B/C patients with risk factors, whereas it was 1.8% (95% confidence interval 0.4-5.3) in those without risk factors ( P < 0.01). In group A, the incidence of recurrence was 3.6% in patients with risk factors, but it was only 0.4% in patients without risk factors ( P < 0.01). The disease-free survival rate of group A patients classified as risk positive was significantly worse than those of groups B and C patients. However, the 5-year disease-free survival rate in group A patients with no risk was 99.6%.

DISCUSSION

Our large-scale real-world multicenter study demonstrated the validity of the JSCCR criteria for pT1 CRC after local resection, especially regarding favorable outcomes in patients with low risk of LNM.

Combined Endoscopy-Laparoscopy Surgery: When and How to Utilize This Tool

Combined endoscopic and laparoscopic surgery (CELS) has been used to resect colon polyps since the 1990s. These colon-sparing techniques, however, have not yet been widely adopted. With the evolution of technology in both diagnosing and treating colon cancer, colorectal surgeons should strive for a diverse and complete armamentarium through which they can best serve their patients. In this article, we hope to provide clarity on CELS by discussing three topics: (1) the history and fruition of CELS; (2) the techniques involved in CELS; and (3) the utility of CELS within different clinical scenarios. Our goal is to educate readers and stimulate consideration of CELS in select patients who might benefit greatly from these techniques.

Barriers to Implementation of Advanced Endoscopic Procedures

Advanced endoscopy has been shown to be useful in the diagnosis and treatment of both benign and low-grade malignant colorectal lesions. In fact, advanced endoscopic procedures are being adopted as standard approaches to these lesions in many places around the world; however, their implementation in the United States has not been as widespread. We ascribe the difficulty in implementation to two reasons: (1) lack of advanced endoscopic training and (2) failure in reimbursement models as they relate to endoscopy. In this article, we hope to describe these barriers and inspire colorectal surgeons to try and overcome them. As surgical specialists with a mastery of endoscopic techniques, colorectal surgeons would be able to maximize benefit for their patients and minimize health care costs in the long run.

Management of T1 Colorectal Cancer

BACKGROUND

Approximately 10% of patients with submucosal invasive (T1) colorectal cancer (CRC) have lymph node metastasis (LNM). The risk of LNM can be stratified according to various histopathological factors, such as invasion depth, lymphovascular invasion, histological grade, and tumor budding.

SUMMARY

T1 CRC with a low risk of LNM can be cured by local excision via endoscopic resection (ER), whereas surgical resection (SR) with lymph node dissection is required for high-risk T1 CRC. Current guidelines raise concern that many patients receive unnecessary SR, even though most patients achieve a radical cure. Novel diagnostic techniques for LNM, such as nomograms, artificial intelligence systems, and genomic analysis, have been recently developed to identify more low-risk T1 CRC cases. Assessing the curability and the necessity of additional treatment, including SR with lymph node dissection and chemoradiotherapy, according to histopathological findings of the specimens resected using ER, is becoming an acceptable strategy for T1 CRC, particularly for rectal cancer. Therefore, complete resection with negative vertical and horizontal margins is necessary for this strategy. Advanced ER methods for resecting the muscle layer or full thickness, which may guarantee complete resection with negative vertical margins, have been developed.

KEY MESSAGE

Although a necessary SR should not be delayed for T1 CRC given its unfavorable prognosis when SR with lymph node dissection is performed, the optimal treatment method should be chosen based on the risk of LNM and the patient's life expectancy, physical condition, social characteristics, and wishes.

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

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.

Lymph node metastasis in T1 colorectal cancer with the only high-risk histology of submucosal invasion depth ≥ 1000 μm

PURPOSE

The number of patients undergoing additional surgery after endoscopic resection (ER) for T1 colorectal cancer (CRC) is increasing. Regarding high-risk histology of lymph node metastasis (LNM) in T1 CRC, a submucosal invasion depth ≥ 1000 μm (T1b) alone may be related to a low incidence of LNM. This study was conducted to clarify the incidence of LNM and to identify factors associated with LNM in T1 CRC with high-risk histology characterized only by T1b.

METHODS

We retrospectively investigated patients with pathological T1b CRC who underwent colorectal resection between 2010 and 2020. Patients were divided into two groups with high-risk histology: those in whom the only high-risk feature was T1b (low-risk T1b group, n = 263), and those with T1b as well as lymphovascular invasion, tumor budding, or poorly differentiated or mucinous adenocarcinoma (high-risk T1b group, n = 289). The incidences of LNM and recurrence were compared. Multivariate analysis was performed to identify factors associated with LNM in the low-risk T1b group.

RESULTS

The incidences of LNM were 3.8% and 21.6% in the Low- and High-risk T1b groups, respectively (p < 0.01), while the 5-year recurrence rates in the two groups were 0.6% and 3.4%, respectively (p = 0.10). Multivariate analysis revealed that only a predominant histological type of moderately differentiated adenocarcinoma (p = 0.04) was independently associated with LNM in the low-risk T1b group.

CONCLUSION

When considering the omission of additional surgery after ER in cases of T1 CRC whose only high-risk histological feature is T1b, attention should be paid to the predominant histological type.

Studies on endoscopic submucosal dissection in the past 15 years: A bibliometric analysis

Background and aims

Endoscopic submucosal dissection (ESD) is an advanced minimally invasive technique for en bloc resection of superficial gastrointestinal lesions, which is drawn an increasing attention from its emergence. This bibliometric analysis is to evaluate the origin, current hotspots, and research trends on ESD.

Methods

A total of 2,131 publications on ESD from 2006 to 2020 were obtained from the Web of Science Core Collection (WoSCC) database. Bibliometric visualization analyses of countries/regions, institutes, authors, journals, references and keywords were performed by CiteSpace V.5.8.R3.

Results

The quantity of publications on ESD increased significantly during the past 15 years. Japan occupied the leading position in terms of research power. Professor Yutaka Saito, together with the institute he belongs, the Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan, were the most productive author and institute, respectively. Colorectal ESD led the main thematic concentrations in ESD research. The most prolific journal was Gastrointestinal Endoscopy. European ESD Guideline was the most frequently co-cited reference. Guideline, meta-analysis, endoscopic resection, poly-glycolic acid sheet, Barrett's esophagus, fibrin glue, risk and colorectal neoplasm will be the active research hotspots in the future.

Conclusions

These findings provide the trends and frontiers in the field of ESD, as well as valuable information for clinicians and scientists to discover the future perspectives with potential collaborators.

Risk factors for vertical incomplete resection in endoscopic submucosal dissection of deep invasive submucosal colorectal cancer

INTRODUCTION

It has been recently reported that deep invasive submucosal (T1b) colorectal cancer (CRC) without other pathological risk factors for lymph node metastasis has a low rate of lymph node metastasis, increasing the possibility of endoscopic submucosal dissection (ESD) in the future. However, ESD for T1b CRC is technically difficult, and some lesions cannot be resected en bloc. This study aimed to identify the risk factors associated with vertical incomplete ESD in T1b CRC.

METHODS

We retrospectively studied 140 pathological T1b CRC lesions that underwent initial ESD at our institution between January 2011 and October 2020, and categorized them into positive vertical margin (PVM) and negative vertical margin (NVM) groups. The risk factors for PVM were examined using univariate and multivariate analyses, and a subgroup analysis for T1b CRC with an obvious depressed surface was performed.

RESULTS

Multivariate analysis revealed obvious depression (hazard ratio [HR]: 7.4; 95% confidence interval [CI]: 2.47-22.5) and severe fibrosis (HR: 11.4; 95% CI: 3.95-33.0) as significant risk factors for PVM. Length of depressed surface ≥12 mm (HR: 6.19; 95% CI: 1.56 -24.6) was identified as an independent predictor of PVM for T1b CRC with an obvious depression.

CONCLUSION

Pathological T1b CRC cases with an obvious depression and severe fibrosis are at a high risk of vertical incomplete ESD.

New scoring system to distinguish deep invasive submucosal and muscularis propria colorectal cancer during colonoscopy: a development and global multicenter external validation study (e-T2 Score)

BACKGROUND AND AIMS

Diagnostics to differentiate deep submucosal invasive (invasion depth ≥1000 μm [T1b]) colorectal cancer (CRC) from muscularis propria invasive (T2) CRC are limited. We aimed to establish and validate a scoring system that differentiates T1b from T2.

METHODS

A multicenter retrospective cross-validation study was performed. Four hundred sixty-one consecutive pathologically confirmed T1b or T2 CRCs were divided into the development (T1b, 222; T2, 189) and internal validation (T1b, 31; T2, 19) cohorts. Eight potential endoscopic findings were evaluated using the development cohort: loss of lobulation, deep depression, demarcated depressed area, protuberance within the depression, expanding appearance, fold convergency, erosion or white plaque, and Borrmann type 2 or 3 tumor. A scoring system that differentiates T1b from T2 was developed, and diagnostic performance was tested using the internal validation cohort by 8 endoscopists. External validation was conducted using 50 CRC images by 4 endoscopists from other institutions, including outside of Japan.

RESULTS

Multivariate analysis identified the following 5 independent predictive endoscopic findings of T2 CRC: deep depression (odds ratio [OR], 2.08; 95% confidence interval [CI], 1.07-4.04), demarcated depressed area (OR, 4.40; 95% CI, 1.39-13.9), 4-fold convergency or more (OR, 3.41; 95% CI, 1.90-6.11), erosion or white plaque (OR, 8.28; 95% CI, 2.77-24.7), and Borrmann type 2 or 3 tumor (OR, 8.76; 95% CI, 3.58-21.5). The area under the receiver-operating characteristic curve (AUROC) was .90 (95% CI, .87-.93) in the development cohort, .80 (95% CI, .76-.85) in the internal validation, and .76 (95% CI, .69-.83) in the external validation.

CONCLUSIONS

We established and validated a new scoring system to differentiate T1b from T2 CRC using 5 simple endoscopic findings.

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.

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.

Predictors of lymph-node metastasis in surgically resected T1 colorectal cancer in Western populations

Background

The risk of lymph-node metastasis (LNM) in T1 colorectal cancer (CRC) has not been well documented in heterogeneous Western populations. This study investigated the predictors of LNM and the long-term outcomes of patients by analysing T1 CRC surgical specimens and patients’ demographic data.

Methods

Patients with surgically resected T1 CRC between 2004 and 2014 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Patients with multiple primary cancers, with neoadjuvant therapy, or without a confirmed histopathological diagnosis were excluded. Multivariate logistic-regression analysis was used to identify the predictors of LNM.

Results

Of the 22,319 patients, 10.6% had a positive lymph-node status based on the final pathology (nodal category: N1 9.6%, N2 1.0%). Younger age, female sex, Asian or African-American ethnicity, poor differentiation, and tumor site outside the rectum were significantly associated with LNM. Subgroup analyses for patients stratified by tumor site suggested that the rate of positive lymph-node status was the lowest in the rectum (hazard ratio: 0.74; 95% confidence interval: 0.63–0.86).

Conclusion

The risk of LNM was potentially lower in Caucasian patients than in API or African-American patients with surgically resected T1 CRC. Regarding the T1 CRC site, the rectum was associated with a lower risk of LNM.

Qualitative and Quantitative Analysis of Posttreatment Strategy After Endoscopic Resection for Patients with T1 Colorectal Cancer at High Risk of Lymph Node Metastasis

BACKGROUND

Although endoscopic resection is increasingly performed to treat submucosal invasive colorectal cancer (T1CRC), approximately 10% are at risk of lymph node metastasis. The Japanese Society for Cancer of the Colon and Rectum guideline indicates that the following risk factors should be considered when deciding whether to perform additional surgical resection with lymph node dissection: depth of T1 invasion, lymphovascular invasion, poor histological grade, and budding grade 2/3. However, there is little information about the prognosis of T1CRC patients, or factors to consider when deciding subsequent treatment of high-risk T1CRC.

METHODS

This retrospective mixed method study was conducted using electronic medical records at Kyoto University Hospital between February 2005 and February 2015. Participants were T1CRC patients at risk of lymph node metastasis with at least one of the above four risk factors. They were assigned either careful follow-up (FU) or additional surgery (AS) through shared decision-making. To identify factors affecting decision-making in the FU group, we performed qualitative content analysis of electronic medical records. The prognosis of the groups was compared using the Kaplan-Meier method and the log-rank test.

RESULTS

Of 161 T1CRC patients, 18 were included in the FU group and 19 in the AS group. The median follow-up time was 39.5 (range 23-126) months for the FU group and 62 (range 22-141) months for the AS group. Factors considered in selecting FU were advanced age, comorbidities, the sole presence of the "depth" risk factor, and lower rectal cancer. For AS, the risk factors cited in the guideline were considered. There was one recurrent case in each group during the research period. There were no significant differences in overall survival, cause-specific survival, or recurrence-free survival between the groups.

CONCLUSIONS

Age, comorbidities, and lower-rectal cancer location were considered in deciding posttreatment strategy among high-risk T1CRC patients, alongside with positive vertical margin, depth, lymphovascular invasion, poor histologic grade, and budding. During the research period, there was no prognostic difference between the FU and AS groups.

Additional surgery after endoscopic submucosal dissection for colorectal cancer: a review of 53 cases

BACKGROUND

Endoscopic submucosal dissection (ESD) allows the en bloc resection of tumors and is particularly indicated for T1 colorectal cancer. The number of patients undergoing additional surgery after colorectal ESD is increasing. This study aimed to retrospectively evaluate the efficacy and long-term outcomes in patients with additional surgery.

METHODS

Of 1018 patients who underwent colorectal ESD in our hospital between February 2010 and July 2018, 53 patients who underwent additional surgery in our hospital were retrospectively analyzed and investigated for their clinicopathological characteristics. The need for additional surgery was determined by a pathological examination according to the guideline [1].

RESULTS

In total, 53 patients (24 men, 29 women; mean age, 68.2 years; mean tumor diameter, 30.5 mm) were included. Laparoscopic surgery was performed in 47 (88.7%) patients. Liver metastases were preoperatively observed in one patient, for whom hepatectomy was simultaneously performed. All procedures included pathological R0 resection. Postoperative complications occurred in 9 (17.0%) patients. There were no complications requiring reoperation. Fifteen (28.3%) patients had a positive vertical margin; of these patients, residual tumor was observed in the resected specimens of two (13.3%) patients. Eight patients (15.1%) had lymph node metastasis (LNM): four (25.0%) and four (10.8%) of 16 and 37 patients with and without vascular invasion, respectively. Eleven patients (20.8%) had grade 2 or 3 tumor budding, and four (36.4%) of these had LNM. Postoperative recurrence was observed in two (3.8%) patients.

CONCLUSION

Additional surgery after ESD for T1 colorectal cancer was effective and had good long-term outcomes.

Pathological risk factors and predictive endoscopic factors for lymph node metastasis of T1 colorectal cancer: a single-center study of 846 lesions

BACKGROUND

Determining the depth of invasion of early stage colorectal cancer has been emphasized as a means of improving endoscopic diagnostic accuracy. Recent studies have focused on other pathological risk factors for lymph node metastasis (LNM). We investigated the significance of depth of invasion and predictive properties of other endoscopic findings.

METHODS

We retrospectively investigated 846 patients with submucosal invasive (T1) colorectal cancer who received an accurate pathological diagnosis and were treated between January 2005 and December 2016. Pathological risk factors associated with LNM were reviewed. We divided patients into groups: low-risk T1 colorectal cancer (LRC; no risk factors) and high-risk T1 colorectal cancer (HRC; exhibiting lymphovascular invasion, tumor budding grade of 2/3, and/or poor differentiation) and studied predictive endoscopic factors for HRC.

RESULTS

Significant risk factors for LNM in multivariate analysis were lymphovascular invasion [odds ratio (OR) 8.09; 95% confidence interval (CI) 3.84-17.1], tumor budding (OR 1.89; 95% CI 1.09-3.29), and histological differentiation (OR 2.09; 95% CI 1.12-3.89). The LNM-positive rate with only deep submucosal invasion was 1.6%. Significant predictive factors for HRC in multivariate analysis identified rectal tumor location (OR 1.92; 95% CI 1.35 -2.72, depression (OR 2.73; 95% CI 1.96 -3.80), protuberance within the depression (OR 2.58; 95% CI 1.39- 4.78), expansiveness (OR 2.39; 95% CI 1.27- 4.50), and loss of mucosal patterns (OR 1.90; 95% CI 1.20 -3.01) as significant factors.

CONCLUSIONS

Rectal tumor location, depression, protuberance within the depression, expansiveness, and loss of mucosal patterns could be predictive factors for HRC.

The utility of a novel colonoscope with retroflexion for colorectal endoscopic submucosal dissection

Background and study aims  The PCF-H290TI/L produced by Olympus is a novel colonoscope equipped with some advantageous features for endoscopic treatment. It is expected to improve the potential for retroflexion and overall endoscope operability, which can reduce the difficulty of performing colorectal ESD. The aim of this study was to evaluate the utility of the novel colonoscope in colorectal ESD. Methods  Three hundred and forty-eight consecutive colorectal lesions resected via ESD between June 2014 and January 2017 at Hiroshima University Hospital were included in the retroflexion ability analysis. We compared the retroflexion potential of PCF-H290TI to that of a conventional endoscope. Two hundred and twenty-seven colorectal lesions located in the left-sided colon and resected with ESD between April 2009 and February 2018 were enrolled in the treatment outcome analysis. Treatment outcomes using PCF-H290TI compared to those of the conventional colonoscope, and outcomes of the PCF-H290TI with retroflexion compared to those of the conventional colonoscope without retroflexion were evaluated by propensity score matching. Results  The retroflexion rate with the PCF-H290TI was 76 %, which was significantly higher than the 44 % rate with the conventional scope. Endoscope operability was better and dissection speed was faster when using the PCF-H290TI with retroflexion compared to the conventional colonoscope without retroflexion. There were no significant differences between the groups in en bloc resection rate and adverse events. Conclusion  Compared to the conventional colonoscope, the PCF-H290TI/L made it easier to perform ESD via a retrograde approach regardless of tumor location, and thus may be useful for performing colorectal ESD.

Dual Red Imaging Maintains Clear Visibility During Colorectal Endoscopic Submucosal Dissection

BACKGROUND

The endoscopic lens becomes clouded and its visibility reduces during colorectal endoscopic submucosal dissection (ESD), especially in cases with submucosal fatty tissue. Dual red imaging (DRI) is a novel image-enhanced endoscopic technique that improves endoscopic visibility.

AIMS

This study aimed to evaluate the predictive factors of submucosal fatty tissue and the clinical usefulness of DRI in maintaining clear visibility during colorectal ESD.

METHODS

The study participants included 586 consecutive patients with 645 colorectal tumors who underwent ESD between January 2014 and July 2017. First, the degree of submucosal fatty tissue was evaluated by reviewing recorded images, and the clinical characteristics of the patients and tumors related to severe submucosal fatty tissue were evaluated. Second, 34 tumors resected using DRI were propensity score-matched in a 1:1 ratio to other resected tumors using white light imaging (WLI), and the degree of endoscope lens cloudiness and clinical outcomes were evaluated.

RESULTS

The proportion of tumors located in the right side of the colon, body mass index (≥ 25, BMI), and hemoglobin A1c (≥ 6.5%, HbA1c) were significantly higher in patients with severe submucosal fatty tissue. The visibility in the DRI group was significantly better than in the WLI group. Treatment outcomes in the DRI group were as good as those in the WLI group.

CONCLUSIONS

Tumor location in the right side of the colon, BMI (≥ 25), and HbA1c (≥ 6.5%) are the predictive factors of severe submucosal fatty tissue. DRI is useful in maintaining clear visibility during colorectal ESD, especially with submucosal fatty tissue.

Risk factors of recurrence in T1 colorectal cancers treated by endoscopic resection alone or surgical resection with lymph node dissection

PURPOSE

The recurrence of T1 colorectal cancers is relatively rare, and the prognostic factors still remain obscure. This study aimed to clarify the risk factors for recurrence in patients with T1 colorectal cancers treated by endoscopic resection (ER) alone or surgical resection (SR) with lymph node dissection, respectively.

METHODS

We reviewed 930 patients with resected T1 colorectal cancers (mean follow-up, 52.3 months). Patients were divided into two groups: those who underwent ER alone (298 cases), and those who underwent initial or additional SR with lymph node dissection (632 cases). Group differences in recurrence-free survival were evaluated using the Kaplan-Meier method and log-rank test. Associations between recurrence and clinicopathological features were evaluated in Cox regression analyses; hazard ratios (HRs) were calculated for the total population and each group.

RESULTS

Recurrence occurred in four cases (1.34%) in the ER group and six cases (0.95%) in the SR group (p = 0.32). Endoscopic resection, rectal location, and poor or mucinous (Por/Muc) differentiation were prognostic factors for recurrence in the total population. Por/Muc differentiation was prognostic factor in both groups. Female sex, depressed-type morphology, and lymphatic invasion were also prognostic factors in the ER group, but not in the SR group.

CONCLUSIONS

Endoscopic resection, rectal location, and Por/Muc differentiation are prognostic factors in the total population. For patients who undergo ER alone, female sex, depressed-type morphology, and lymphatic invasion are also risk factors for recurrence. For such patients, regional en-bloc surgery with lymph node dissection could reduce the risk of recurrence.

Clinical outcomes of deep invasive submucosal colorectal cancer after ESD

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) is a reliable method that can replace surgery under certain conditions. However, limited information is available on the clinical course of T1b colorectal cancer (CRC) after ESD. The aim of the study was to clarify the feasibility of ESD for T1b CRC.

PATIENTS AND METHODS

Three hundred and two patients with 312 T1 CRC were identified in this retrospective cohort study. All patients were treated with ESD, other endoscopic treatments, or surgery. In this study, we (I) investigated the en bloc resection rate of ESD and (II) compared the overall survival (OS) rate for patients who underwent ESD with additional surgery (Group A) and surgery without upfront endoscopic resection (Group B) for T1b CRC.

RESULTS

No significant differences were observed in the en bloc resection rates between T1b and T1a CRC (100 vs. 98.7%), but the en bloc R0 resection rate was significantly lower in T1b CRC than in T1a CRC (64.7 vs. 97.4%). Regarding complications, perforations occurred in 2.9% of patients with T1b CRC, which was not significantly different from the rate of 5.3% in patients with T1a CRC. No significant differences were observed in the OS or recurrence-free survival (RFS) curves between Groups A and B (OS rates at 5 years: 92.3 vs. 88.9%, RFS rates at 5 years: 81.4 vs. 85.3%). Similarly, the 5-year disease-specific survival (DSS) rate of Group A was identical to that of Group B (both 100%).

CONCLUSIONS

ESD for T1b CRC before surgery is a possible strategy because of the low rate of complications and favorable long-term outcomes.

Predictive microRNAs for lymph node metastasis in endoscopically resectable submucosal colorectal cancer

Accurate prediction of regional lymph node metastasis (LNM) in endoscopically resected T1-stage colorectal cancers (CRCs) can reduce unnecessary surgeries. To identify miRNA markers that can predict LNM in T1-stage CRCs, the study was conducted in two phases; (I) miRNA classifier construction by miRNA-array and quantitative reverse transcription PCR (qRT-PCR) using 36 T1-stage CRC samples; (II) miRNA classifier validation in an independent set of 20 T1-stage CRC samples. The expression of potential downstream target genes of miRNAs was assessed by immunohistochemistry. In the discovery analysis by miRNA microarray, expression of 66 miRNAs were significantly different between LNM-positive and negative CRCs. After qRT-PCR validation, 11 miRNAs were consistently significant in the combined classifier construction set. Among them, miR-342-3p was the most significant one (P=4.3×10-4). Through logistic regression analysis, we developed a three-miRNA classifier (miR-342-3p, miR-361-3p, and miR-3621) for predicting LNM in T1-stage CRCs, yielding the area under the curve of 0.947 (94% sensitivity, 85% specificity and 89% accuracy). The discriminative ability of this system was consistently reliable in the independent validation set (83% sensitivity, 64% specificity and 70% of accuracy). Of the potential downstream targets of the three-miRNAs, expressions of E2F1, RAP2B, and AKT1 were significantly associated with LNM. In conclusion, this classifier can predict LNM more accurately than conventional pathologic criteria and our study results may be helpful to avoid unnecessary bowel surgery after endoscopic resection in early CRC.

Endoscopic Approach for Superficial Colorectal Neoplasms

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in males and the second in females, with an estimated 1.4 million cases and 693,900 deaths in 2012. Colonoscopy is the cornerstone for the detection and prevention of CRC. In addition, endoscopic treatment for CRC at an early stage can effectively improve patients' quality of life and cure rate.

SUMMARY

This review focuses on endoscopic approaches, including white light endoscopy, chromoendoscopy, magnifying endoscopy and therapeutic endoscopy, for the evaluation and treatment of superficial colorectal neoplasms.

KEY MESSAGE

Understanding the preoperative evaluation, indications and techniques of endoscopic mucosal resection/endoscopic submucosal dissection as well as postoperative surveillance for superficial colorectal neoplasms is critical for providing appropriate management to the patients.

PRACTICAL IMPLICATIONS

Endoscopic therapy, a method preserving organ function and improving quality of life, is a widely applied microinvasive treatment for superficial colorectal neoplasms. This review describes the basics and developments of endoscopic approaches and may facilitate daily practice for superficial colorectal neoplasms.

Long-term outcomes after treatment for pedunculated-type T1 colorectal carcinoma: a multicenter retrospective cohort study

BACKGROUND

The risk for lymph node metastasis and the prognostic significance of pedunculated-type T1 colorectal carcinomas (CRCs) require further study. We aimed to assess the validity of the 2014 Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines based on long-term outcomes of pedunculated-type T1 CRCs.

METHODS

In this multicenter retrospective cohort study, we examined 176 patients who underwent resection endoscopically or surgically at 14 institutions between January 1990 and December 2010. Patients meeting the JSCCR curative criteria were defined as "endoscopically curable (e-curable)" and those who did not were "non-e-curable". We evaluated the prognosis of 116 patients (58 e-curable, 58 non-e-curable) who were observed for >5 years after treatment.

RESULTS

Overall incidence of lymph node metastasis was 5 % (4/81; 95 % confidence interval 1.4-12 %: three cases of submucosal invasion depth ≥1000 μm [stalk invasion] and lymphatic invasion, one case of head invasion and budding grade 2/3). There was no local or metastatic recurrence in the e-curable patients, but six of them died of another cause (observation period, 80 months). There was no local recurrence in the non-e-curable patients; however, distant metastasis was observed in one patient. Death due to the primary disease was not observed in non-e-curable patients, but six of them died of another cause (observation period, 72 months).

CONCLUSIONS

Our data support the validity of the JSCCR curative criteria for pedunculated-type T1 CRCs. Endoscopic resection cannot be considered curative for pedunculated-type T1 CRC with head invasion alone.

Endoscopic Submucosal Dissection for the Complete Resection of the Rectal Remnant Mucosa in a Patient With Familial Adenomatous Polyposis

A 47-year-old woman underwent prophylactic subtotal colectomy with ileorectal anastomosis (IRA) for familial adenomatous polyposis (FAP) 18 years ago. She underwent 5 transanal endoscopic microsurgeries for rectal remnant polyps, and was referred for the treatment of rectal remnant polyp recurrence. Endoscopic submucosal dissection (ESD) was performed to remove multiple polypoid lesions that circumferentially extended throughout the rectal remnant with lesions spreading onto the anastomotic site. The rectal remnant mucosa was resected in 2 pieces without complication. Specimens showed high-grade adenoma but no malignancy. Follow-up colonoscopy showed no recurrence.

Management of colorectal T1 carcinoma treated by endoscopic resection

As a result of recent advances in endoscopic therapeutic technology, the number of endoscopic resections carried out in the treatment of early colorectal carcinomas with little risk of lymph node metastasis has increased. There are no reports of lymph node metastasis in intramucosal (Tis) carcinomas, whereas lymph node metastasis occurs in 6.8-17.8% of submucosal (T1) carcinomas. Three clinical guidelines have been published in Japan and the management strategy for early colorectal tumors has been demonstrated. According to the 2014 Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines for the Treatment of Colorectal Cancer, additional surgery should be done in cases of endoscopically resected T1 carcinoma with a histologically diagnosed positive vertical margin. Additional surgery may also be considered when one of the following histological findings is detected: (i) SM invasion depth ≥1000 µm; (ii) histological type por., sig., or muc.; (iii) grade 2-3 tumor budding; and (iv) positive vascular permeation. A resected lesion that is histologically diagnosed as a T1 carcinoma without any of the above-mentioned findings can be followed up without additional surgery. As for the prognosis of endoscopically resected T1 carcinomas, the relapse ratio of approximately 3.4% (44/1312) is relatively low. However, relapse is associated with a poor prognosis, with 72 cancer-related deaths reported out of 134 relapsed cases (54%). A more detailed stratification of the lymph node metastasis risk after endoscopic resection for T1 carcinomas and the prognosis of relapsed cases will be elucidated through prospective studies. Thereafter, the appropriate indications and safe and secure endoscopic resection for T1 carcinomas will be established.

How to deal with large colorectal polyps: snare, endoscopic mucosal resection, and endoscopic submucosal dissection; resect or refer?

PURPOSE OF REVIEW

The importance of accurate polyp detection and removal is paramount to preventing colon cancer. Resection of large polyps can be challenging to the endoscopist based on their size, shape, or location. Large polyps have the potential of harboring malignancy and a higher risk of complications with resection. Careful assessment of each lesion and meticulous resection using the appropriate tools and techniques is essential.

RECENT FINDINGS

Over the last 15 years, the development of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) techniques has presented the endoscopist with the opportunity to manage patients with large and flat lesions thereby avoiding the need for surgery. However, these techniques are complex and require extensive knowledge and skill in the use of various devices to resect a lesion completely and manage bleeding and perforation associated with these procedures.

SUMMARY

Large colon polyps manifest as either polypoid or nonpolypoid (flat) lesions. Polypoid lesions, especially those with pedicles, are removed with snare resection, whereas flat lesions may require the use of EMR or ESD. Resection of large polyps (>1 cm) requires additional tools and techniques to ensure safe and complete resection. We will discuss our approach to dealing with large colorectal polyps: snare, EMR, and ESD; resect or refer?

Practical problems of measuring depth of submucosal invasion in T1 colorectal carcinomas

PURPOSE

Submucosal invasion depth (SID) in colorectal carcinoma (CRC) is an important factor in estimating risk of lymph node metastasis, but can be difficult to measure, leading to inadequate or over-extensive treatment. Here, we aimed to clarify the practical aspects of measuring SID in T1 CRC.

METHODS

We investigated 568 T1 CRCs that were resected surgically at our hospital from April 2001 to December 2013, and relationships between SID and clinicopathological factors, including the means of measurement, lesion morphology, and lymph node metastasis.

RESULTS

Of these 568 lesions, the SID was ≥1000 μm in 508 lesions. SIDs for lesions measured from the surface layer were all ≥1000 μm. Although lesions with SIDs ≥1000 μm were associated with significantly higher levels of unfavorable histologic types and lymphovascular infiltration than shallower lesions, a depth of ≥1000 μm was not a significant risk factor for lymph node metastasis (LNM) (6.7 vs. 9.8 %; P = 0.64), and no lesions for which the sole pathological factor was SID ≥1000 μm had lymph node metastasis. Protruded lesions showed deeper SIDs than other types.

CONCLUSIONS

Although we found several problems of measuring SID in this study, we also found, surprisingly, that SID is not a risk factor for lymph node metastasis, and its measurement is not needed to estimate the risk of lymph node metastasis.