The feasibility of endoscopic resection for colorectal laterally spreading tumors

The present study aimed to investigate the feasibility and safety of endoscopic resection for colorectal laterally spreading tumors (LSTs) in different size groups. This retrospective study included 2699 patients with LSTs who underwent endoscopic treatment at the Second Xiangya Hospital of Central South University from May 2012 to February 2022. The patient baseline and procedure outcomes were compared between the < 5 cm group, 5-10 cm group, and ≥ 10 cm group. Meanwhile, lesions larger than 5 cm in diameter were longitudinally compared for endoscopic safety using ESD with surgical operation outcomes. There were 2105 patients in the < 5 cm group, 547 patients in the 5-10 cm group, and 47 patients in the ≥ 10 cm group. En bloc resection and R0 resection rates, the incidence of adverse events, length of stay (LOS), and medical costs significantly differed between the groups (P < 0.01). Comorbidity of diabetes or hypertension, history of antithrombotic drug use, lesion size, location, gross type, endoscopic procedures selection, and circumferential extent of the mucosal defect were independent risk factors for delayed bleeding (P < 0.05). En bloc resection, R0 resection, and lesion canceration were associated with local recurrence. For lesions larger than 5 cm in diameter, ESD had similar R0 resection and local recurrence rates compared with a surgical operation but a lower en bloc rate, LOS, and medical costs. Expert endoscopists can significantly increase en bloc and R0 resection rates and reduce the incidence of adverse events. Endoscopic resection results distinguish in different size groups of colorectal LSTs, yet its safety and feasibility are not inferior to a surgical operation.

Large colonic lipoma with a laterally spreading tumor treated by endoscopic submucosal dissection: A case report

BACKGROUND

Since fat does not transmit electrical energy well, delayed perforation and post-polypectomy syndrome due to electrical thermal injury are concerns in the endoscopic removal of colonic lipoma. The endoscopic submucosal dissection (ESD) technique concentrates electrical energy conducts to the submucosa, not the adipose tissue. This helps to minimize electrical thermal injury, especially in the case of large colonic lipomas. In rare cases, such as colonic lipomas accompanied by mucosal lesions, it is difficult for endoscopists to decide how to safely remove them.

CASE SUMMARY

A 78-year-old man underwent colonoscopy for colorectal cancer screening. During colonoscopy, a yellowish submucosal tumor with positive cushion sign was observed in the ascending colon measuring about 4.5 cm. A nodular mucosal lesion of about 2.5 cm was observed on the mucosal surface of the lipoma. The lipoma was so large that it occupied much of the inside of the colon, making it difficult to see the entire laterally spreading tumor (LST) at once. The LST was confined to the surface of the lipoma, which had a semipedunculated shape with a wide neck. The margin of the LST was not observed at the neck of the lipoma. ESD was performed and the colonic lipoma with the LST was successfully removed without complications. After 3 d of hospitalization, the patient was discharged without any symptoms. The final pathology report showed that the lesion consisted of submucosal lipoma and tubulovillous adenoma with low-grade dysplasia.

CONCLUSION

ESD is effective and safe for treating a large colonic lipoma with an LST by minimizing electrical thermal injury.

Integrated Analysis Identifies Novel Fusion Transcripts in Laterally Spreading Tumors Suggestive of Distinct Etiology Than Colorectal Cancers

BACKGROUND

Laterally spreading tumors (LSTs) of the colon and rectum are a class of abnormality which spreads laterally and appears ulcerated. They are a subclass of colorectal cancer (CRCs) with higher invasive potential than CRCs. Moreover, the etiology of LST still remains obscure.

METHODS

This study aimed to identify unique fusion transcript(s) in LSTs and evaluate their role in LST development and progression. RNA-Seq data for LST samples from the EMBL-EBI database were used to identify fusion transcripts. An integrated approach using Gene Ontology, pathway analysis, hub gene, and co-expression network analysis functionally characterized fusion transcripts to shed light upon the etiology of LSTs.

RESULT

We identified 48 unique fusion genes in LSTs. GO terms were enriched in mRNA metabolic (p ≤ 2.06E-06), mRNA stabilization (p ≤ 1.60E-05), in cytosol (1.20E-05), RBP (p ≤ 2.30E-04), and RNA binding activity (p ≤ 3.51E-08) processes. Pathway analysis revealed an inflammatory phenotype of LSTs suggesting a distinct etiology than CRCs as pathways were enriched in salmonella infection (p ≤ 4.41 e-03), proteoglycans in cancer (p ≤ 1.18 e-02), and insulin signaling (p ≤ 2.13 e-02). Our exclusion and inclusion criteria and hub gene analysis finally identified 9 hub genes. Co-expression analysis of hub genes identified the most significant transcription factors (NELFE, MYC, TAF1, MAX) and kinases (MAPK14, CSNK2A1, CDK1, MAPK1) which were implicated in various cancer pathways. Furthermore, an overall survival analysis of hub genes was performed. Our predefined criterion resulted in the enrichment of NPM1-PTMA (NPM1: p ≤ 0.005) and HIST1H2BO-YBX1 (YBX1: p ≤ 0.02) fusion transcripts, significantly associated with the patient's overall survival.

CONCLUSION

Our systematic analysis resulted in novel fusion genes in LSTs suggesting a different etiology than CRCs. Fusion transcripts were observed more frequently in non-granular LSTs suggestive of genetically more unstable than granular LST. We hypothesize that NPM1-PTMA and HIST1H2BO-YBX1 could be implicated in LST development and progression and may also serve as a prognostic or diagnostic biomarker in future for better management of LSTs.

Laterally spreading tumor-like primary rectal mucosa-associated lymphoid tissue lymphoma: A case report

BACKGROUND

Colorectal mucosa-associated lymphoid tissue (MALT) lymphoma is a rare disease, and only a few cases have been reported to date. It has no specific clinical presentations and shows various endoscopic appearances. There is no uniform consensus on its treatment. With the advancement of endoscopic technology, endoscopic treatment has achieved better results in individual case reports of early-stage patients.

CASE SUMMARY

We report a case of rectal MALT in a 57-year-old Chinese man with no symptoms who received endoscopy as part of a routine physical examination, which incidentally found a 25 mm × 20 mm, laterally spreading tumor (LST)-like elevated lesion in the rectum. Therefore, he was referred to our hospital for further endoscopic treatment. Complete and curable removal of the tumor was performed by endoscopic submucosal dissection. We observed enlarged and dilated branch-like vessels similar to those of gastric MALT lymphoma on magnifying endoscopy with narrow-band imaging. And immunopathological staining showed hyperplastic capillaries in the mucosa. Histopathological findings revealed diffusely hyperplastic lymphoid tissue in the lamina propria, with a visible lymphoid follicle structure surrounded by a large number of diffusely infiltrated lymphoid cells that had a relatively simple morphology and clear cytoplasm. In addition, immunohistochemical analysis suggested strongly positive expression for CD20 and Bcl-2. Gene rearrangement results showed positivity for IGH-A, IGH-C, IGK-B, and IGL. Taking all the above findings together, we arrived at a diagnosis of extranodal marginal zone B-cell lymphoma of MALT lymphoma. Positron emission tomography-computed tomography examination showed no other lesions involved. The patient will be followed by periodic endoscopic observation.

CONCLUSION

In conclusion, we report a case of rectal MALT with an LST-like appearance treated by endoscopic submucosal dissection. Further studies will be needed to explore the clinical behavior, endoscopic appearance, and treatment of rectal MALT.

Factors Associated with Fibrosis during Colorectal Endoscopic Submucosal Dissection: Does Pretreatment Biopsy Potentially Elicit Submucosal Fibrosis and Affect Endoscopic Submucosal Dissection Outcomes?

BACKGROUND

Submucosal fibrosis observed during colorectal endoscopic submucosal dissection (ESD) is an important factor related to incomplete resection. Biopsy is generally accepted as having the potential to elicit submucosal fibrosis, but few reports have presented definitive proof. This study investigated the relation between submucosal fibrosis and colorectal ESD outcomes and assessed factors related to fibrosis, including pretreatment biopsy.

METHODS

After reviewing 369 records of colorectal ESD performed between January 2011 and December 2016, we assessed the relation between fibrosis and ESD outcomes. Multiple logistic regression analysis revealed fibrosis risk factors.

RESULTS

Severe fibrosis was related significantly to ESD outcomes such as the mean procedure time (p < 0.001), en bloc resection rate (p < 0.001), and R0 resection rate (p = 0.011). Multivariate analyses indicated residual lesions (ORs 175.4, p < 0.001), pretreatment biopsy (ORs 8.30, p = 0.002), nongranular-type laterally spreading tumors (LST-NG; ORs 5.86, p = 0.025), and invasive carcinoma (ORs 5.83, p = 0.03) as independent risk factors of severe fibrosis. In each macroscopic type, LST-NG was more strongly related to fibrosis induced by pretreatment than granular-type laterally spreading tumors with adjust ORs of 50.8 and 4.69.

CONCLUSIONS

Pretreatment biopsy causes submucosal fibrosis resulting in prolonged procedure times and incomplete resection. These findings suggest important benefits of avoiding biopsy before ESD.

Application value of pre-cutting endoscopic mucosal resection in treatment of colorectal laterally spreading tumors

BACKGROUND

Endoscopic mucosal resection (EMR) with precutting (Pre-cut-EMR) is an improvement on the basis of EMR, which combines the technical advantages of EMR and endoscopic submucosal dissection (ESD) to form a new endoscopic resection method and is more and more widely used in clinical practice. This study preliminarily explored the clinical value of Pre-cut-EMR in the treatment of colorectal laterally spreading tumors (LSTs) through retrospective analysis.

AIM

To explore the application value of Pre-cut-EMR in the treatment of colorectal LSTs.

METHODS

A total of 84 patients with colorectal LSTs who were treated at our department from January 2016 to December 2019 were selected as the research subjects. The clinical data of all patients were retrospectively analyzed to summarize the clinical characteristics of colorectal LSTs. All patients underwent Pre-cut-EMR, and the average operation time, overall resection rate, complete resection rate, and the incidence of complications were recorded. Colonoscopy was performed at 3, 6, and 12 mo after the operation to evaluate the recurrence. The relevant literature on ESD treatment of colorectal LSTs was retrieved through China HowNet and Wanfang Database, and the pre-cut-EMR group and ESD group were compared for the curative effect on colorectal LSTs.

RESULTS

The average diameter of colorectal LSTs in the 84 cases was 25.6 mm. The endoscopic morphological classification was mainly granular. According to Kudo pit classification, types Ⅲ and Ⅳ were common, with type ⅢL being the most common. Tubular adenoma and villous adenoma were common pathological types. All 84 patients with colorectal LSTs underwent endoscopic resection successfully. One of them converted to ESD and one to EPMR. The pre-cut-EMR resection rate was 97.6%, and the average operation time was 24.5 min. There were three cases with positive basal margins, and the complete resection rate was 96.4%. Two cases of bleeding and one case of perforation occurred during the operation, and the complication rate was 3.6%. None of the 78 patients who were followed had recurrence, and the recurrence rate was 0%. Compared with the research data obtained by Xu et al, Yu et al, and Qiuhai et al, the operation time of the Pre-cut-EMR group was significantly lower than that of the ESD group (χ² = 21.037, P = 0.001), but there was no statistical difference in the overall resection rate, complication rate, complete resection rate, or recurrence rate compared with the ESD group (P > 0.05).

CONCLUSION

Pre-cut-EMR is effective and safe for colorectal LST treatment, and has high clinical value. This surgical method deserves to be widely promoted due to its simplicity, being easy to learn, and low equipment requirements.

Blue laser imaging combined with JNET (Japan NBI Expert Team) classification for pathological prediction of colorectal laterally spreading tumors

BACKGROUND

Blue laser imaging (BLI) can provide useful information on colorectal laterally spreading tumors (LSTs) by visualizing the surface and vessel patterns in detail. The present research aimed to evaluate the diagnostic performance of BLI-combined JNET (Japan NBI Expert Team) classification for identifying LSTs.

METHODS

This retrospective, multicenter study included 172 LSTs consisted of 6 hyperplastic polyps/sessile serrated polyps, 94 low-grade dysplasias (LGD), 60 high-grade dysplasias (HGD), 6 superficial submucosal invasive (m-SMs) carcinomas, and 4 deep submucosal invasive carcinomas. The relationship between the JNET classification and the histologic findings of these lesions were then analyzed.

RESULTS

For all LSTs, non-experts and experts had a 79.7% and 90.7% accuracy for Type 2A (P = 0.004), a sensitivity of 94.7% and 96.8% (P = 0.718), and a specificity of 61.5% and 83.3% (P = 0.002) for prediction of LGD, respectively. The results also demonstrated 80.8% and 91.3% accuracy for Type 2B (P = 0.005), a sensitivity of 65.2% and 83.3% (P = 0.017), and a specificity of 90.6% and 96.2% (P = 0.097) for predicting HGD or m-SMs. For LST-granular (LST-G) lesions, Type 2A in experts had higher specificity (65.6% vs. 83.6%, P = 0.022) and accuracy (81.8% vs. 91.2%, P = 0.022). Type 2B in experts only had higher accuracy (82.5% vs. 92.0%, P = 0.019). However, no significant differences were noted for any comparisons between non-experts and experts for LST-non-granular (LST-NG) lesions.

CONCLUSIONS

BLI combined with JNET classification was an effective method for the precise prediction of pathological diagnosis in patients with LSTs. Diagnostic performance of JNET classification by experts was better than that by non-experts for all examined LST or LST-G lesions when delineating between Type 2A and 2B, but there was no difference for the identification of LST-NG lesions by these two groups.

Long-term outcomes of endoscopically resected laterally spreading tumors with a positive histological lateral margin

BACKGROUND

With advances in diagnostic endoscopy, the incidence of superficial colorectal tumors, including laterally spreading tumors (LSTs), has increased. However, little is known about the long-term results of LSTs with positive lateral margin after endoscopic treatment. This study aimed to evaluate the long-term clinical outcomes and risk factors for local recurrence of LSTs with positive lateral margin after initial endoscopic resection.

METHODS

We performed a retrospective analysis of the medical records of 324 patients who had 363 LSTs with positive lateral margin after endoscopic resection at a tertiary academic medical center. The medical records from 2011 to 2015 were analyzed. Local recurrence was confirmed through endoscopic finding and subsequent biopsy analysis. We assessed the local recurrence rate and performed multivariate analyses to identify the factors associated with local recurrence.

RESULTS

Follow-up colonoscopy was performed in 176 of 363 LSTs. The local recurrence rate was 6.3% (11/176), with a median (interquartile range [IQR]) follow-up period of 19.8 (12.4-46.5) months. In multivariate analysis, local recurrence was associated with piecemeal resection (odds ratio [OR] 6.62, 95% confidence interval [CI] 1.28-34.33; p = 0.024) and inversely associated with thermal ablation (OR 0.033, 95% CI 0.00-0.45; p = 0.011). At surveillance colonoscopy, histology of the recurrent tumor was adenoma in 10 (90.9%) of 11; these were treated endoscopically.

CONCLUSIONS

In this retrospective study, we found that endoscopically resected LSTs with positive lateral margin have a low recurrence rate. Piecemeal resection was associated with higher local recurrence, and thermal ablation was inversely associated with local recurrence. Endoscopic resection with positive lateral margin combined with thermal ablation leads to a low recurrence rate.

Effect of Preceding Biopsy on the Results of Endoscopic Submucosal Dissection for Colorectal Laterally Spreading Tumor

BACKGROUND

Forceps biopsies are usually performed before endoscopic submucosal dissection (ESD) for colonic laterally spreading tumors (LSTs). However, preceding biopsy is commonly believed to possibly inhibit complete tumor resection by causing blurring of tumor borders and tissue fibrosis.

AIMS

The aims were to investigate whether the preceding biopsy of colorectal LST affects the complete endoscopic tumor resection and increases the risk of complications.

METHODS

We retrospectively reviewed the medical records of patients with colorectal LSTs who underwent ESD at our center during an 8-year period. Patients were divided into two groups according to whether they underwent biopsy of the tumor before ESD. In addition, the characteristics of patients and tumors, including the completeness of tumor resection, were investigated.

RESULTS

Of 288 patients (174 men) enrolled in this study, 194 (67.4%, preceding biopsy group) underwent biopsies before ESD, whereas 94 (32.6%, no biopsy group) did not. There were no significant differences in age, sex, comorbidity, medication history, tumor location, and final pathologic result between both groups. Tumor size was larger (p = 0.002) and LST-G tumor was more common (p = 0.003) in the preceding biopsy group than in the no biopsy group. No significant difference was seen in ESD outcomes, including procedure time, hospitalization period, incidence of complications, en bloc resection rate, resection margin status, and incidence of surgical operation, between both groups.

CONCLUSIONS

Biopsy of LST is commonly performed before endoscopic resection. Contrary to popular belief, it does not increase the incomplete tumor resection rate and incidence of complications.

TRIAL REGISTRATION

KCT0002321.

Integrated Analysis of the Endoscopic, Pathological and Molecular Characteristics of Colorectal Tumorigenesis

BACKGROUND

Colorectal cancers (CRCs) develop through the accumulation of genetic and epigenetic alterations of oncogenes and tumor suppressor genes. In addition to the well-characterized adenoma-carcinoma sequence, the serrated neoplasia pathway is now recognized as an alternative pathway for CRC development.

SUMMARY

Through analysis of the colonoscopic, pathological, and molecular features of colorectal tumors, we identified a novel microsurface structure characteristic of serrated lesions. The Type II-Open (Type II-O) pit pattern is highly specific to sessile serrated adenoma/polyps (SSA/Ps), and Type-II-O-positive tumors frequently exhibit v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation and 5'-C-phosphate-G-3' (CpG) island hypermethylation. By screening DNA methylation associated with the development of serrated lesions, we detected methylation of secreted protein acidic and rich in cysteine (SPARC)-related modular calcium binding 1 (SMOC1) in traditional serrated adenomas (TSAs). Epigenetic silencing of SMOC1 is prevalent among TSAs but it is rarely observed in SSA/Ps, which suggests SMOC1 could be a useful diagnostic marker of serrated lesions. We also searched for epigenetic alterations associated with the growth pattern of colorectal tumors and found that methylation of neurotensin receptor 1 is associated with lateral and non-invasive tumor growth. Key Message: Through the summarized studies, we have been able to identify novel morphological and molecular features that could contribute to a better understanding of colorectal tumors and to improved clinical diagnosis.

Long-term prognosis after treatment for T1 carcinoma of laterally spreading tumors: a multicenter retrospective study

PURPOSE

Long-term prognosis of T1 laterally spreading tumors (LSTs) after treatment have not been clarified. This study compared clinicopathological characteristics and long-term prognosis of T1 LSTs.

METHODS

We retrospectively assessed 169 patients with 169 T1 LSTs between January 1992 and December 2008 by ten hospitals. Patients who did not meet the Japanese Society for Cancer of the Colon and Rectum (JSCCR) 2016 guidelines for the treatment of colorectal carcinoma (CRC) criteria were defined as non-endoscopically curable. The number of non-endoscopically curable patients with LST-granular/ nodular mixed (LST-G-M) was 61, that with LST-non-granular/ flat elevated (LST-NG-FE) was 23, and that with LST-non-granular/ pseudo depressed (LST-NG-PD) was 23. Clinicopathological variables and long-term prognosis were analyzed.

RESULTS

For overall patients, tumor size, number of non-endoscopically curable cases, and rate of submucosal invasion depth ≥ 1000 μm for the LST-G-M group were significantly higher than those in the other groups. For non-endoscopically curable patients, the tumor size for those with LST-G-M was significantly larger than those in the other groups. The rate of submucosal invasion width ≥ 4000 μm and type B/C muscularis mucosae with LST-G-M was higher than that with LST-NG-FE. All recurrences occurred in non-endoscopically curable patients with LST-G-M. Five-year overall and disease-free survivals for non-endoscopically curable patients with LST-G-M were significantly shorter than those for patients with non-endoscopically curable LST-NG-FE and PD.

CONCLUSIONS

Our data supported adequacy of the JSCCR guidelines for the treatment of CRC criteria for endoscopically curable patients after T1 LSTs treatment. Patients with T1 LST-G-M should be followed up more carefully.

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.

Prophylactic Suturing Closure Is Recommended after Endoscopic Treatment of Colorectal Tumors in Patients with Antiplatelet/Anticoagulant Therapy

The prophylactic closure of mucosal defects after endoscopic resection is known to prevent postoperative bleeding in colorectal lesions. However, closure of large mucosal defects is difficult with conventional clips only, and several closure techniques have been previously described; use of an Endoloop, 8-ring loop, or loop clip and a small incision around the mucosal defect. Given that the prophylactic closure requires much cost and time, the application should be limited to high-risk cases. Medication of antithrombotics or antiplatelet agents would be one of the reasonable indications for prophylactic closure of mucosal defects after endoscopic resection of colorectal tumors.

Successful endoscopic submucosal dissection of colon cancer with severe fibrosis after tattooing

Endoscopic tattooing is often used to facilitate the identification of colorectal lesions before endoscopic treatments. However, tattooing under the lesion can result in technical difficulties because of the dark endoscopic field and submucosal fibrosis. A 65-year-old man with a non-granular-type laterally spreading tumor was referred to our hospital after tattooing with India ink for surgery. However, endoscopic submucosal dissection (ESD) was selected for the resection of this lesion because the findings of magnifying endoscopy suggested an intramucosal cancer. Dissection around a dense section was difficult because of the dark endoscopic field and non-lifting as a result of severe fibrosis. We performed ESD using the following strategy: (1) injection with a smaller amount of indigo carmine and (2) cut and dissection from the side of the thinly tattooed area. The lesion was curatively resected en bloc without any complications. This finding suggests that endoscopic tattooing before endoscopic treatment should be performed one or two folds away from the lesion.

Analysis of molecular alterations in laterally spreading tumors of the colorectum

BACKGROUND

Colorectal laterally spreading tumors (LSTs) are classified into LST-Gs and LST-NGs, according to macroscopic findings. In the present study, we determined the genetic and epigenetic alterations within colorectal LSTs and protruding adenomas.

METHODS

A crypt isolation method was used to isolate DNA from tumors and normal glands of 73 macroscopically verified colorectal LSTs (histologically defined adenomas; 38 LST-Gs and 35 LST-NGs) and 36 protruding adenomas. The DNA was processed using polymerase chain reaction (PCR) microsatellite assays, single-strand conformation polymorphism (SSCP) assays, and pyrosequencing to detect chromosomal allelic imbalance (AI), mutations in APC, KRAS, and TP53, and the methylation of MLH1, MGMT, CDKN2A, HPP1, RASSF2A, SFRP1, DKK1, ZFP64, and SALL4 genes. In addition, methylation status was examined using the following set of markers: MIN1, MINT2, MINT31, MLH1, and CDKN2A (with classification of negative/low and high). Microsatellite instability (MSI) was also examined.

RESULTS

5q AI and methylation of the SFRP1 and SALL4 genes were common molecular events in both LST-Gs and LST-NGs. Neither MSI nor mutations in BRAF ware observed in the LSTs. TP53 mutations were rarely found in LSTs. The frequencies of KRAS and APC mutations and the methylation levels of ZFP64, RASSF2A, and HPP1 genes were significantly higher in LST-Gs than in LST-NGs. Protruding adenomas showed alterations common to LST-Gs. Negative/low methylation status was common among the three types of tumors.

CONCLUSION

Combined genetic and epigenetic data suggested that the molecular mechanisms of tumorigenesis were different between LST-Gs and LST-NGs.

Colonic Laterally Spreading Tumor Diagnosed as an Early Cancer and Treated with Endoscopic Mucosal Resection: A Case Report and Review of Literature

Laterally spreading tumors (LSTs) are generally defined as superficial lesions ≥10 mm in diameter that typically extend laterally rather than vertically along the colonic wall. Such lesions are now increasingly reported because of increased awareness and the introduction of chromo and magnifying colonoscopy. Although the clinicopathological characteristics and the efficacy of endoscopic management of LSTs have been defined in Japanese cohorts, reports from the Middle East are lacking where surgical resection is the mainstay of treatment. We report a case with an LST about 20 cm from anal verge removed by endoscopic mucosal resection. After histopathological evaluation of the removed specimen, we categorized the patient as having high risk early colon cancer. The intensive follow-up as an additional treatment strategy was chosen for the patient. This review addresses the management of early carcinoma in colorectal polyp with reference to proper preoperative assessment, treatment selection with special attention to role of biomarkers, the need for additional treatment on the basis of the presence of risk factors and endoscopic follow-up after treatment.

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.

Multi-band mucosectomy for resection of a giant colorectal laterally spreading tumor: A case report

Endoscopic submucosal resection (EMR) and endoscopic submucosal dissection (ESD) are acceptable modalities for the ablation of colorectal laterally spreading tumors (LSTs), however, there are limitations when treating giant LSTs with ESD due to the technical difficulty and adverse events. In the case presented here, we employed Duette Multi-band mucosectomy to successfully perform a complete endoscopic ablation of a giant LST without any adverse events, which may provide a new strategy for endoscopic management of giant LSTs.

Laterally spreading tumors: Limitations of computed tomography colonography

AIM: To prospectively investigate the detection rate of laterally spreading tumors (LSTs) of the colorectum by computed tomography (CT) colonography (CTC).

METHODS: Patients with LSTs measuring ≥ 20 mm detected during colonoscopy were prospectively enrolled in the study. All patients underwent colonoscopy and subsequent CTC on the same day. CTC was performed using multi-detector CT without contrast in the prone and supine positions. Two radiologists blinded to the existence of LSTs read the virtual endoscopic images as well as 2-D images. LSTs were classified into granular and non-granular types based on colonoscopic appearance.

RESULTS: Forty-seven pathologically proven LSTs were evaluated prospectively. Histology included adenomas in 19, mucosal cancers in 19 and T1 cancers in 9. The mean diameter of the LSTs was 35.1 mm. Twenty-eight (60%) LSTs were correctly identified by CTC, and the configuration was similar to the colonoscopic appearance in most cases. Detection rate for the granular type was significantly higher than that for the non-granular type (71% vs 31%, P = 0.013). Detection rate of adenomas was significantly lower than mucosal cancers (32% vs 79%, P = 0.008) and T1 cancers (32% vs 78%, P = 0.042).

CONCLUSION: The detection rate of LSTs by CTC, particularly the non-granular type was not acceptable. Practitioners should be aware of the relatively low detection rate when using CTC.

MUC5AC/β-catenin expression and KRAS gene alteration in laterally spreading colorectal tumors

AIM: To clarify differences in mucin phenotype, proliferative activity and oncogenetic alteration among subtypes of colorectal laterally spreading tumor (LST).

METHODS: LSTs, defined as superficial elevated lesions greater than 10 mm in diameter with a low vertical axis, were macroscopically classified into two subtypes: (1) a granular type (Gr-LST) composed of superficially spreading aggregates of nodules forming a flat-based lesion with a granulonodular and uneven surface; and (2) a non-granular type (NGr-LST) with a flat smooth surface and an absence of granulonodular formation. A total of 69 LSTs, comprising 36 Gr-LSTs and 33 NGr-LSTs, were immunohistochemically stained with MUC2, MUC5AC, MUC6, CD10 (markers of gastrointestinal cell lineage), p53, β-catenin and Ki-67 antibodies, and examined for alteration in exon 1 of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and exon 15 of v-raf murine sarcoma viral oncogene homologue B1 (BRAF) by polymerase chain reaction followed by direct sequencing.

RESULTS: Histologically, 15 Gr-LST samples were adenomas with low-grade dysplasia (LGD), 12 were high-grade dysplasia (HGD) and 9 were adenocarcinomas invading the submucosa (INV), while 12 NGr-LSTs demonstrated LGD, 14 HGD and 7 INV. In the proximal colon, MUC5AC expression was significantly higher in the Gr-type than the NGr-type. MUC6 was expressed only in NGr-LST. MUC2 or CD10 did not differ. P53 expression demonstrated a significant stepwise increment in progression through LGD-HGD-INV with both types of LST. Nuclear β-catenin expression was significantly higher in the NGr-type. Ki-67 expression was significantly higher in the Gr-type in the lower one third zone of the tumor. In proximal, but not distal colon tumors, the incidence of KRAS provided mutation was significantly higher in the Gr-type harboring a specific mutational pattern (G12V). BRAF mutations (V600E) were detected only in two Gr-LSTs.

CONCLUSION: The two subtypes of LST, especially in the proximal colon, have differing phenotypes of gastrointestinal cell lineage, proliferation and activation of Wnt/β-catenin or RAS/RAF/extracellular signal-regulated kinase signaling.

Endoscopic submucosal dissection for large laterally spreading tumors involving the ileocecal valve and terminal ileum

Endoscopic submucosal dissection is a challenging technique that enables en-bloc resection for large colorectal tumors, as laterally spreading tumors, particularly difficult, if the ileocecal valve and terminal ileum is involved. Herein, we report on one of 4 cases. The procedures, using a bipolar needle knife (B-Knife) to reduce the perforation risk and carbon dioxide instead of conventional air insufflation for patient comfort, achieved curative resections without any complications.

Balloon overtube-guided colorectal endoscopic submucosal dissection

AIM: To evaluate the usefulness of a balloon overtube to assist colorectal endoscopic submucosal dissection (ESD) using a gastroscope.

METHODS: The results of 45 consecutive patients who underwent colorectal ESD were analyzed in a single tertiary endoscopy center. In preoperative evaluation of access to the lesion, difficulties were experienced in the positioning and stabilization of a gastroscope in 15 patients who were thus assigned to the balloon-guided ESD group. A balloon overtube was placed with a gastroscope to provide an endoscopic channel to the lesion in cases with preoperatively identified difficulties related to accessibility. Colorectal ESD was performed following standard procedures. A submucosal fluid bleb was created with hyaluronic acid solution. A circumferential mucosal incision was made to marginate the lesion. The isolated lesion was finally excised from the deeper layers with repetitive electrosurgical dissections with needle knives. The success of colorectal ESD, procedural feasibility, and procedure-related complications were the main outcomes and measurements.

RESULTS: The overall en bloc excision rate of colorectal ESD during this study at our institution was 95.6%. En bloc excision of the lesion was successfully achieved in 13 of the 15 patients (86.7%) in the balloon overtube-guided colorectal ESD group, which was comparable to the results of the standard ESD group with better accessibility to the lesion (30/30, 100%, not statistically significant).

CONCLUSION: Use of a balloon overtube can improve access to the lesion and facilitate scope manipulation for colorectal ESD.