Endoscopic mucosal resection of flat and depressed types of early colorectal cancer

Endoscopic treatment for early stage colorectal tumors: the comparison between EMR with small incision, simplified ESD, and ESD using the standard flush knife and the ball tipped flush knife

BACKGROUND

Early stage colorectal tumors can be removed by endoscopic mucosal resection but larger such tumors (20 mm) may require piecemeal resection. Endoscopic submucosal dissection (ESD) using newly developed endo-knives has enabled en-block resection of lesions regardless of size and shape. However ESD for colorectal tumor is technically difficult. Therefore, we performed EMR with small incision (EMR with SI) for more reliable EMR, ESD with snaring (simplified ESD) and ESD using the standard Flush knife and the novel ball tipped Flush knife (Flush knife BT) for easier and safer colorectal ESD.

AIMS

The aims of our study were (1) to compare the treatment results of the following 3 methods (EMR with SI/si-mplified ESD/ESD) for early stage colorectal tumors, and (2) to assess the performance of Flush knife BT in colorectal ESD.

METHODS

We treated 24/44/468 colorectal tumors and examined the clinicopathological features and treatment results such as tumor size, resected specimen size, procedure time, en-bloc resection rate, complication rate. We also treated 58 colorectal tumors (LST-NG:20, LST-G:36, other:2) using standard Flush knife and 80 colorectal tumors (LST-NG:32, LSTG:44, other:2) using Flush knife BT, and examined the clinicopathological features and treatment results mentioned above and also the procedure speed.

RESULT

The median tumor size (mm) (EMR with SI/ simplified EMR/ESD) was 20/17/30 (EMR with SI vs. simplified ESD: p = n.s, simplified ESD vs. ESD: p < 0.0001). The median resected specimen size (mm) was 22.5/26/41 (EMR with SI vs. simplified ESD: p = 0.0018, simplified ESD vs. ESD: p < 0.0001). The procedure time (min.) was 19/27/60 (EMR with SI vs. simplified ESD: p = n.s, simplified ESD vs. ESD: p < 0.0001) The en-block resection rate (%) was 83.3/90.9 /98.9. The complication rate (post-operative bleeding rate/perforation p=n.s). In the treatment results of ESD for LSTs by knives, there was no difference between standard Flush knife and Flush knife BT for clinicopathological features and treatment results (procedure time, complication rate and en bloc R0 resection rate). However, procedure speed (cm2/min.) of LST-G was significantly faster in the Flush knife BT than in standard Flush knife. (standard Flush knife: 0.21 vs. Flush knife BT: 0.27, p = 0.034).

CONCLUSION

EMR with small incision (EMR with SI) and ESD with snaring (simplified ESD) are good option to fill the gap between EMR and ESD in the colorectum, and also considered to become the nice training for the introduction of ESD. Flush knife BT appears to improve procedure speed compared with standard Flush knife, especially for LST-G in colo-rectal ESD.

Outcomes of endoscopic resection of large colorectal neoplasms: an Australian experience

BACKGROUND AND AIMS

Endoscopic resection of large colorectal neoplasms is increasingly being used as an alternative to surgery. However data on failure rates, safety and long-term outcomes remain limited. The aim of the study was to report short- and long-term outcomes from endoscopic resection of large colorectal neoplasms from a single centre and use a model to predict mortality had surgery been performed.

METHODS

Consecutive patients referred for endoscopic resection of large (> or = 20 mm) colorectal neoplasms from January 2001 to February 2008 were included. Resection details were recorded in a prospectively maintained database. Data was collected on 30-day complication rates, and follow-up colonoscopy findings. The Colorectal-POSSUM score was used to estimate mortality from open surgery.

RESULTS

There were 154 large neoplasms in 140 patients. Mean age was 68 years (range 22-94). Mean neoplasm size was 26 mm (range 20-80 mm, 24 > or = 40 mm). Complete endoscopic removal was achieved in 95% of cases. Twenty patients were referred for surgery (14%). In the endoscopy group, there were no deaths within 30 days. Twelve patients had a complication including two perforations. Endoscopic follow-up data was available in 90% of cases and five patients (4%) were found to have residual adenoma that was treated endoscopically with subsequent clearance. If surgery had been performed, the mean predicted mortality was 2.2% (range 0.5-10%). There were two deaths (10%) in patients who underwent elective surgery within 30 days.

CONCLUSION

Endoscopic resection of large colorectal neoplasms is safe and effective even for very large benign neoplasms. When the lesion is endoscopically resectable this should be the preferred treatment.

Early gastric cancer: lymph node metastasis starts with deep mucosal infiltration

OBJECTIVE

The purpose of this study was to evaluate the frequency of lymph node metastasis according to the depth of tumor infiltration of the mucosa and submucosa.

BACKGROUND DATA

Currently some endoscopists extend the indication for endoscopic mucosal resection in gastric cancer to the submucosa. However, the decision between endoscopic mucosectomy or gastrectomy with lymphadenectomy for early gastric cancer depends especially on the probability of lymph node metastasis.

METHODS

One hundred twenty-six patients either had subtotal resection (n = 29) or total gastrectomy (n = 97) for T1 gastric cancer. The median number of resected lymph nodes was 21 (1-63). In the histopathologic analysis of the specimens the tumors were differentiated according to their wall penetration in the upper (m1), middle (m2), lower (m3) third of the mucosa or submucosa (sm1, sm2, sm3). The greatest diameter of the lesions, the Grading and the Goseki-, Ming-, WHO-, and Laurén classification were determined.

RESULTS

Patients with m1 (n = 3) and m2 (n = 5) layer infiltration had no lymphatic metastasis compared with 13% for m3 (n = 39). The rate of lymphatic metastasis in submucosal carcinomas was 21% for sm1 (n = 29), 16% for sm2 (n = 23) and 40% for sm3 (n = 25). Carcinomas with papillary differentiation, Grading G1 or <1 cm in diameter had no lymph node metastasis. The size of tumor <2 cm or > or =2 cm showed independent influence on the rate of lymph node metastasis.

CONCLUSIONS

Endoscopic mucosectomy in m3 carcinoma is questionable and in all submucosal carcinomas and lesions > or =2 cm it is not indicated.

Comparative study of conventional colonoscopy, magnifying chromoendoscopy, and magnifying narrow-band imaging systems in the differential diagnosis of small colonic polyps between trainee and experienced endoscopist

BACKGROUND

Removal of colorectal neoplastic polyps can reduce the incidence of colorectal cancers. It is important to distinguish neoplastic from nonneoplastic polyps. We compared the ability of a trainee and an experienced endoscopist in distinguishing between neoplastic polyps and nonneoplastic polyps by conventional white-light, magnifying narrow-band imaging (NBI), and magnifying chromoendoscopy.

MATERIALS AND METHODS

One hundred and sixty-three small colorectal polyps from 104 patients were studied. All polyps were diagnosed by trainees and experienced endoscopists using conventional white-light, magnifying NBI, and magnifying chromoendoscopy. The kappa values of interobserver agreement between trainees and experienced endoscopists were evaluated before this study. Sensitivity, specificity, and diagnostic accuracy were assessed by reference to histopathology. The first 50 polyps were diagnosed by the trainee as the first stage and the rest 113 polyps were diagnosed as the second stage.

RESULTS

Magnifying NBI and magnifying chromoendoscopy were significant better than conventional white-light by the experienced endoscopist (diagnostic accuracy: NBI 85.3%, chromoendoscopy 87.7%, conventional view 74.8%). No significant differences were found for the trainee. The kappa values (0.77 approximately 0.85) were good for each endoscopic modality for the experienced endoscopist. However, only NBI and chromoendoscopy had acceptable kappa values (0.40 approximately 0.48) for the trainee. The trainee improved diagnostic accuracy in the second stage, but not yielded the level of the experienced endoscopist.

CONCLUSION

Magnifying NBI and magnifying chromoendoscopy had a better interobserver agreement than conventional white-light among trainees and experienced endoscopists. The trainee needs learning time to improve diagnostic ability, even using a new modality such as magnifying NBI.

Transoral endoscopic inner layer esophagectomy: management of high-grade dysplasia and superficial cancer with organ preservation

INTRODUCTION

Limitations of endoscopic therapies for Barrett's esophagus and superficial cancer include a compromised histological assessment, the need for surveillance, subsequent procedures, and stricture formation. Circumferential en bloc resection of the mucosa-submucosa complex followed by deployment of a biologic scaffold onto the remaining muscularis propria may address these concerns. The objective of this study was to determine technical feasibility of transoral resection of the esophageal lining.

MATERIALS AND METHODS

Transoral endoscopic inner layer esophagectomy was performed in ten swine. Endpoints included procedure duration, hemorrhage, number of perforations, and adequacy of resection length and depth.

RESULTS

Procedures were successfully completed in all animals without perioperative mortality. Procedure times averaged 179 min (range 125-320). No perforations were found, and a mean of 1.7 (0-4) interventions for hemorrhage was required. Complete longitudinal resection was achieved in nine of ten animals. Resection depth included all mucosal layers in 100% of tissue sections, the submucosal layers, SM1 in 100%, and SM2 in 96%. A portion of SM3 was adherent to the muscularis propria in 70%.

CONCLUSION

Transoral endoscopic resection of the inner esophageal layers was feasible and reproducible. This technique may facilitate a single-step definitive treatment and staging tool for early neoplastic lesions, obviating the need for esophagectomy.

The creation of a peritoneal defect in transanal endoscopic microsurgery does not increase complications

INTRODUCTION

During Transanal Endoscopic Microsurgical (TEMS) full-thickness excision of a rectal lesion above the peritoneal reflection, entrance to the peritoneal cavity is inevitable. This has been regarded as a complication that requires conversion to an open procedure. We describe our experience of full thickness intraperitoneal excision of rectal lesions where the peritoneal defect was sutured endoscopically.

METHOD

Data were collected prospectively on 15 patients in whom a peritoneal defect was created intraoperatively during TEMS excision of a rectal lesion. When a defect was recognized, it was closed by endoscopic suture. If there was any doubt regarding security of the closure, a defunctioning loop stoma was fashioned.

RESULTS

Between November 1998 and January 2008, a total of 257 patients underwent TEMS during which a peritoneal defect was created in 15 patients. Six patients had a defunctioning stoma formed at the time of TEMS. No patient was defunctioned postoperatively and there were no deaths. The mean hospital stay was 8 days (range 3 to 19 days). A contrast enema showed sub-clinical leaks in two patients for which no treatment was required. No patient developed pelvic or peritoneal sepsis, but one patient had to return to theatre for postoperative bleeding when a single bleeding vessel was coagulated.

CONCLUSION

Full thickness excision of lesions in the intraperitoneal rectum with endoscopic suture of the defect is a safe procedure. Lesions in the upper rectum should not be excluded from TEMS excision because of the chance of peritoneal breach.

The value of high-resolution three-dimensional endorectal ultrasonography in the management of submucosal invasive rectal tumors

PURPOSE

The aims of this prospective study were 1) to evaluate the accuracy of high-resolution three-dimensional endorectal ultrasonography in distinguishing slight from massive submucosal invasion of early rectal tumors, and 2) to determine the technology's role in treatment selection.

METHODS

A total of 142 consecutive patients with clinically possible pT1 rectal cancers underwent three-dimensional endorectal ultrasonography. Slight or massive irregularity of the hyperechoic submucosal layer was considered to characterize uT1-slight or uT1-massive tumors. Treatment was selected on the basis of ultrasonographic findings: endoscopic resection or full-thickness transanal local excision was selected for uT1-slight lesions, and radical resection was selected for uT1-massive tumors. Ultrasonographic staging was compared with histopathologic staging.

RESULTS

One hundred twenty-six patients were included in the final analyses. Three-dimensional endorectal ultrasonography staged 77 lesions as uT0, 25 as uT1-slight, 20 as uT1-massive, and 4 as uT2. Histologically, adenomas were found in 75 patients and tumor invasion was found in 44 lesions (24 pT1-slight, 16 pT1-massive, 4 pT2). The overall kappa for the concordance between ultrasonographic and histopathologic stagings was 0.81 (95% confidence interval, 0.72-0.89). No invasive carcinomas remained undetected. The depth of invasion was correctly determined in 87.2% of both pT1-slight and pT1-massive lesions. Considering the complete series of 126 patients, the accuracy of this modality in selecting appropriate management was 95.2% (kappa, 0.84; 95% confidence interval, 0.71-0.96). Adequate surgery was performed in 87.5% of pT1 tumors.

CONCLUSION

Three-dimensional endorectal ultrasonography is useful for assessing the depth of submucosal invasion in early rectal cancer and for selecting therapeutic options.

The use of indigocarmine spray increases the colonoscopic detection rate of adenomas

PURPOSE

It remains controversial whether chromocolonoscopy using indigocarmine increases the detection of colorectal polyps. We aimed to assess the impact of indigocarmine dye spray on the detection rate of adenomas and the feasibility of learning the technique in a Western practice.

METHODS

400 patients were prospectively allocated into 2 groups; A (n = 200): indigocarmine chromocolonoscopy was performed by a Japanese colonoscopist with expertise in chromoscopy; B (n = 200): initial 100 patients (B-1), a Western colonoscopist with no previous experience of chromoscopy performed conventional colonoscopy, but with at least 10 min observation during colonoscopy withdrawal. In the next 100 patients (B-2), he performed chromocolonoscopy. All polyps found were resected. Regression analysis was used to compare the numbers of polyps detected in groups A, B-1 and B-2, whilst controlling for gender, age, indication and history of colorectal cancer.

RESULTS

There were significant differences in the numbers of neoplastic polyps and flat adenomas between groups A and B-1 as well as between B-1 and B-2, but not between A and B-2. There was no significant difference in numbers of advanced lesions. Chromocolonoscopy (A and B-2) detected more neoplastic polyps of <or=5 mm.

CONCLUSION

Chromocolonoscopy increases the detection of neoplastic polyps and flat adenomas, particularly diminutive polyps, but does not increase the detection of advanced lesions.

Lymphatic vessel invasion detected by monoclonal antibody D2-40 as a predictor of lymph node metastasis in T1 colorectal cancer

OBJECTIVE

When selecting patients who are at high risk for lymph node metastasis, the detection of lymphatic vessel invasion (LVI) is important. We investigated LVI detected by D2-40 staining as a predictor of lymph node metastasis in T1 colorectal cancer.

MATERIALS AND METHODS

Clinicopathological factors including LVI were investigated in 136 patients who underwent colectomy with lymph node dissection for T1 colorectal cancer. We used immunostaining with monoclonal antibody D2-40 to detect LVI.

RESULTS

Lymph node metastases were found in 18 patients (13.2%), and LVI were detected in 45 (33%); lymph node metastasis was more frequently observed in LVI-positive groups (13/45 vs 5/91, p < 0.001). Both univariate and multivariate analyses revealed that LVI detected by D2-40 and a poorly differentiated histology at the invasion front were independent risk factors of lymph node metastasis.

CONCLUSION

LVI detected by D2-40 is important for the prediction of lymph node metastasis.

Treatment strategy for laterally spreading tumors in Japan: before and after the introduction of endoscopic submucosal dissection

BACKGROUND AND AIMS

Laterally spreading tumors (LST) in the colorectum are considered good candidates for endoscopic resection (ER). Because LST-non-granular (NG) tumors show multifocal invasion into the submucosal layer, en bloc resection is necessary for adequate histopathological evaluation. Therefore, surgical resection has been recommended when a lesion is suspected to be an invasive cancer and too large to resect en bloc. The aim of the present study was to evaluate whether the introduction of colorectal ESD, which was developed for en bloc resection of early gastric cancers, could improve the en bloc resection rate of large LST-NG-type tumors and reduce the surgical resection rate.

METHODS

Between January 1999 and December 2005, a total of 166 LST-NG-type tumors measuring > or = 20 mm in 161 patients were included in this study. The en bloc resection rate and the surgical resection rate were historically compared between two periods, before and after the introduction of ESD.

RESULTS

The en bloc resection rate for ER lesions was significantly higher in the latter period (35.0% [14/40]vs 76.5% [75/98]; P < 0.001), and the rate of surgery for adenomas and intramucosal or sm minute cancers was significantly lower in the latter period (20.0% [10/50]vs 1.1% [1/89]; P < 0.001).

CONCLUSIONS

The introduction of colonic ESD was able to change our treatment strategy for LST, improving the en bloc resection rate and reducing the surgical resection rate.

Endoscopic mucosal resection for early colorectal neoplasia: pathologic basis, procedures, and outcomes

Open access endoscopy and screening programs enable detection and removal of an increased number of colon polyps in the early stages of neoplastic transformation. Unfortunately, polyps larger than 3 cm, involving more than one-third of circumference or two haustral folds, or with a flat/depressed morphology are more challenging to remove with standard polypectomy techniques. Endoscopic mucosal resection potentiates the removal, in a minimally invasive way, of certain colonic lesions that would otherwise require surgical or ablative treatment. Because the plane of resection during endoscopic mucosal resection is typically the middle to deep submucosal layer, compared with standard polypectomy, which normally provides resection at a mucosal level, endoscopic mucosal resection offers the advantage of providing en bloc resection specimens for histopathologic analysis. Indications to perform endoscopic mucosal resection are adenoma and small, well-differentiated carcinoma, confined to the mucosa or with minimal invasion to submucosa, and without any invasion to lymphatic channels or vessels. The most frequently reported major complications, such as perforation (0-5%) and bleeding (0.5-6%), may be controlled by endoscopic methods and rarely require surgical treatment. Follow-up postendoscopic mucosal resection is essential because of the risk of neoplastic recurrence.

Knack and practical technique of colonoscopic treatment focused on endoscopic mucosal resection using snare

Endoscopic mucosal resection (EMR) is one of the main treatment modalities for broad-based protruded-type or flat-type lesions of colorectal tumors. In this report, the procedures and skills required for EMR, which forms the basis of colonoscopic treatment, are described based on the current situation. The knack of EMR is to understand the characteristics and selection of an adequate snare in each situation, selection of adequate local injection drug, to learn techniques of local injection, to master skilful snaring techniques, to estimate the degree of radial cure of locally resected regions using magnifying observation and the practice of additional trimming. As a result of the practice and learning of these points, EMR, including piecemeal resection, can be enough for curative treatment of colorectal tumor. We can and should differentiate EMR from endoscopic submucosal dissection (ESD) for various types of colorectal tumor according to detailed endoscopic diagnosis using magnification prior to treatment.

Therapeutic strategy for colorectal laterally spreading tumor

Most colorectal tumors larger than 20 mm in diameter are called laterally spreading tumors (LST), most of which are adenomatous lesions. Laterally spreading tumors are classified into two types according to their morphology, granular type (LST-G) and non-granular type (LST-NG). Each type has two subtypes. The former consists of a 'homogenous type' and a 'nodular mixed type', while the latter consists of a 'flat elevated (FE) type' and a 'psedodepressed (PD) type'. In LST-G and LST-NG FE types, type V pit pattern with magnification enables the recognition of the carcinomatous or submucosal invasive area. Most of these adenomatous large lesions can be cured by scheduled endoscopic piecemeal mucosal resection (EPMR). However, LST-G with large whole nodular type or type V pit pattern, which cannot be resected en bloc with a snare, is an indication for endoscopic submucosal dissection (ESD). The LST-NG PD has a high frequency of submucosal invasion and the submucosal invasive area cannot be recognized correctly in the pseudodepression with magnification prior to endoscopic treatment. Therefore, en bloc resection with ESD should be applied to LST-NG PD. The therapeutic strategy for choosing between EPMR and ESD for large LST lesions should therefore be determined based on the macroscopic findings of their subtype and pit pattern findings.

Clinical outcome of endoscopic submucosal dissection versus endoscopic mucosal resection of large colorectal tumors as determined by curative resection

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) has recently been applied to the treatment of superficial colorectal cancer. Clinical outcomes compared with conventional endoscopic mucosal resection (EMR) have not been determined so our aim was to compare the effectiveness of ESD with conventional EMR for colorectal tumors >or=20 mm.

METHODS

This was a retrospective case-controlled study performed at the National Cancer Center Hospital in Tokyo, Japan involving 373 colorectal tumors >or=20 mm determined histologically to be curative resections. Data acquisition was from a prospectively completed database. We evaluated histology, tumor size, procedure time, en bloc resection rate, recurrence rate, and associated complications for both the ESD and EMR groups.

RESULTS

A total of 145 colorectal tumors were treated by ESD and another 228 were treated by EMR. ESD was associated with a longer procedure time (108 +/- 71 min/29 +/- 25 min; p < 0.0001), higher en bloc resection rate (84%/33%; p < 0.0001) and larger resected specimens (37 +/- 14 mm/28 +/- 8 mm; p = 0.0006), but involved a similar percentage of cancers (69%/66%; p = NS). There were three (2%) recurrences in the ESD group and 33 (14%) in the EMR group requiring additional EMR (p < 0.0001). The perforation rate was 6.2% (9) in the ESD group and 1.3% (3) in the EMR group (p = NS) with delayed bleeding occurring in 1.4% (2) and 3.1% (7) of the procedures (p = NS), respectively, as all complications were effectively treated endoscopically.

CONCLUSIONS

Despite its longer procedure time and higher perforation rate, ESD resulted in higher en bloc resection and curative rates compared with EMR and all ESD perforations were successfully managed by conservative endoscopic treatment.

Endoscopy, morphology, morphometry and molecular markers: predicting cancer risk in colorectal adenoma

The evaluation of short- and long-term risk for developing cancer in patients with colorectal adenomas is controversial. Good, reliable predictors of cancer risk in any adenoma are currently lacking and are limited to adenoma size, number and histologic type. In fact, the evaluation of any adenoma or precancer lesion (e.g., hyperplastic polyps, serrated adenoma or aberrant crypt foci) within the colorectum may be assessed by a number of techniques ranging from direct visualization through the endoscope, to microscopic assessment, and to evaluation at the molecular level. Emerging techniques may yield improved methods of adenoma risk-assessment in the near future. For one, newer endoscopy technologies include chromoendoscopy or endocytoscopy, which now render endoscopists able to resolve the surface and subsurface mucosa at cellular resolution in vivo and in real time - thus, bringing the microscope to the patient's bedside. This new era in endoscopic imaging is dubbed 'histoendoscopy'. Further, while traditional views of classifying protruding and sessile lesions include those of Haggitt, the sm-classification, the Japanese and the so-called Vienna classifications to evaluate neoplasia, the development of new molecular techniques may give way to new methods of classifying preneoplasia and precancerous lesions. This review discusses some pros and cons of risk evaluation technologies in the colorectal tract by endoscopy, microscopy, and quantitative and molecular features. The morphometry-based studies performed over the past decades for the quantitative assessment of cellular and nuclear features within adenomas have failed to yield results amenable for clinical translation and are unlikely to improve further and gain widespread use with current technology. Rather, emerging knowledge of pathway-specific markers through the outlining of a molecular classification will likely be the basis for improved detection and diagnosis. The emerging genomic and proteomic technologies allowing for noninvasive tests to detect (asymptomatic) cancer and neoplasia are discussed. Lastly, the importance of recognizing bias and pitfalls and the adherence to guidelines for biomarker research are addressed.

Indications for subsequent surgery after endoscopic resection of submucosally invasive colorectal carcinomas: a prospective cohort study

PURPOSE

This study explored predictive factors that affected oncologic outcomes after surgical resection or follow-up without surgery in patients with submucosally invasive colorectal carcinomas after endoscopic resection.

METHODS

Oncologic outcomes in terms of lymph node metastasis or tumor recurrence were assessed according to resection margin, histology, and depth of invasion.

RESULTS

Eighty-seven patients with submucosally invasive colorectal carcinomas after endoscopic resection were followed prospectively. Fifty-seven (65.5 percent) patients had risk factors of deep submucosal invasion and/or unfavorable histology. Among them, 30 underwent radical resection, and 6 patients had lymph node metastases. Twenty patients with risk factors were closely followed up and 3 recurrent carcinomas were detected. Ultimately, 9 of 57 high-risk patients (15.8 percent) exhibited lymph node metastasis or tumor recurrence. Among 30 patients without risk factors, none had lymph node metastasis or recurrent carcinoma. Univariate analysis showed that tumor budding (P = 0.003) and venous invasion (P = 0.021) were factors for lymph node metastasis. In multivariate analysis, only tumor budding was an independent predictor of lymph node metastasis (P = 0.026).

CONCLUSIONS

Approximately 16 percent of patients with submucosally invasive colorectal carcinoma and risk factors benefited from subsequent surgery. Tumor budding was the most significant factor for lymph node metastasis. Observation would be appropriate for patients without risk factors after endoscopic resection.

Local excision for rectal carcinoma

Local excision is an alternative approach to radical proctectomy for rectal cancer, but from an oncologic standpoint, it is a compromise, and its role remains controversial. Careful patient selection is essential because local excision is generally considered only for early rectal cancer with no evidence of nodal metastasis, parameters that can be predicted by clinical examination, and various radiologic modalities with variable accuracy. In this review, we present the literature evaluating the oncologic adequacy of local excision, including transanal endoscopic microsurgery and the results of salvage surgery after local excision. An overview of local excision in the context of perioperative adjuvant therapies is included. Finally, we suggest a treatment algorithm for local excision in rectal cancer.

Submucosal injection solution for gastrointestinal tract endoscopic mucosal resection and endoscopic submucosal dissection

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have provided new alternatives for minimally invasive treatment of gastrointestinal adenomas and early-stage cancers that involve a minimum risk of lymph-node metastasis. The use of submucosal injections is essential to the success of these endoscopic resection techniques. The “ideal” submucosal injection solution should provide a sufficiently high submucosal fluid cushion for safe and effective EMRs and ESDs while also preserving lesion tissue for accurate histopathological assessment. In the past, normal saline (NS) solution was commonly used for this purpose, but it is difficult to achieve the proper submucosal elevation and maintain the desired height with NS. Therefore, other safe and effective facilitative submucosal injection solutions have been developed that also take into account relevant cost-benefit considerations. This review examines recent advances in the development of effective submucosal injection solutions for use during endoscopic resections.

Local recurrence after endoscopic resection of colorectal tumors

BACKGROUND AND AIMS

Local recurrence frequently occurs after endoscopic resection of large colorectal tumors. However, appropriate intervals for surveillance colonoscopy to assess local recurrence after endoscopic resection have not been clarified. The aim of the present study was to determine local recurrence rates following en-bloc and piecemeal endoscopic resection and establish appropriate surveillance colonoscopy intervals based on retrospective analysis of local recurrences.

MATERIALS AND METHODS

A total of 461 patients with 572 > or = 10-mm lesions underwent endoscopic resection and follow-up. We retrospectively compared local recurrence rates on lesion size, macroscopic type, and histological type after en-bloc resection (440 lesions) and piecemeal resection (132 lesions). Cumulative local recurrence rates were analyzed using the Kaplan-Meier method.

RESULTS

Local recurrence occurred for 34 lesions (5.9%). Local recurrence rates for the en-bloc and piecemeal groups was 0.7% (3/440) and 23.5% (31/132), respectively (P < 0.001). The difference between the two groups was distinct in terms of lesion size, macroscopic type, and histological type. Of the 34 local recurrences, 32 were treated endoscopically and two cases required additional surgery. The 6-, 12-, and 24-month cumulative local recurrence rate of the en-bloc group was 0.24%, 0.49%, and 0.81%. Then the 6-, 12-, and 24-month cumulative local recurrence rate for the piecemeal group was 18.4%, 23.1%, and 30.7%.

CONCLUSION

Local recurrence occurred more frequently after piecemeal resection than en-bloc resection. However, almost all cases of local recurrences could be cured by additional endoscopic resection, so piecemeal resection can be acceptable treatment.

Colorectal endoscopic submucosal dissection: present status and future perspective, including its differentiation from endoscopic mucosal resection

Endoscopic submucosal dissection (ESD) allows en bloc resection of a lesion, irrespective of the size of the lesion. ESD has been established as a standard method for the endoscopic ablation of malignant tumors in the upper gastrointestinal (GI) tract in Japan. Although the use of ESD for colorectal lesions has been studied via clinical research, ESD is not yet established as a standard therapeutic method for colorectal lesions because colorectal carcinoma has unique pathological, organ specific characteristics that differ radically from those of the esophagus and stomach, and scope handling and control is more difficult in the colorectum than in the upper GI tract. Depending on the efficacy of endoscopic mucosal resection (EMR) and the clinicopathological characteristics of the colorectal tumor, the proposed indications for colorectal ESD are as follows: (1) lesions difficult to remove en bloc with a snare EMR, such as nongranular laterally spreading tumors (particularly the pseudo depressed type), lesions showing a type VI: pit pattern, and large lesions of the protruded type suspected to be carcinoma; (2) lesions with fibrosis due to biopsy or peristasis; (3) sporadic localized lesions in chronic inflammation such as ulcerative colitis; and (4) local residual carcinoma after EMR. Colorectal ESD is currently in the development stage, and a standard protocol will be available in the near future. We hope that colorectal tumors will be efficiently treated by a treatment method appropriately selected from among EMR, ESD, and surgical resection after precise preoperative diagnosis based on techniques such as magnifying colonoscopy.

Usefulness and safety of 0.4% sodium hyaluronate solution as a submucosal fluid "cushion" for endoscopic resection of colorectal mucosal neoplasms: a prospective multi-center open-label trial

BACKGROUND

Sodium hyaluronate (SH) solution has been used for submucosal injection in endoscopic resection to create a long-lasting submucosal fluid "cushion". Recently, we proved the usefulness and safety of 0.4% SH solution in endoscopic resection for gastric mucosal tumors. To evaluate the usefulness of 0.4% SH as a submucosal injection solution for colorectal endoscopic resection, we conducted an open-label clinical trial on six referral hospitals in Japan.

METHODS

A prospective multi-center open-label study was designed. A total of 41 patients with 5-20 mm neoplastic lesions localized in the colorectal mucosa at six referral hospitals in Japan in a single year period from December 2002 to November 2003 were enrolled and underwent endoscopic resection with SH. The usefulness of 0.4% SH was assessed by the en bloc complete resection and the formation and maintenance of mucosal lesion-lifting during endoscopic resection. Safety was evaluated by analyzing adverse events during the study period.

RESULTS

The usefulness rate was high (82.5%; 33/40). The following secondary outcome measures were noted: 1) steepness of mucosal lesion-lifting, 75.0% (30/40); 2) intraoperative complications, 10.0% (4/40); 3) time required for mucosal resection, 6.7 min; 4) volume of submucosal injection, 6.8 mL and 5) ease of mucosal resection, 87.5% (35/40). Two adverse events of bleeding potentially related to 0.4% SH were reported.

CONCLUSION

Using 0.4% SH solution enabled sufficient lifting of a colorectal intramucosal lesion during endoscopic resection, reducing the need for additional injections and the risk of perforation. Therefore, 0.4% SH may contribute to the reduction of complications and serve as a promising submucosal injection solution due to its potentially superior safety in comparison to normal saline solution.

Increased expression of beta-catenin, phosphorylated glycogen synthase kinase 3beta, cyclin D1, and c-myc in laterally spreading colorectal tumors

Laterally spreading tumors (LSTs) are considered a special subtype of superficial colorectal tumor. This study was performed to characterize the clinicopathological features and examine activation of the Wnt/beta-catenin pathway in LSTs and protruded-type colorectal adenomas (PAs). Fifty LSTs and 54 PAs were collected, and their clinicopathological characteristics were compared. The expression of E-cadherin, beta-catenin, glycogen synthase kinase-3beta (GSK-3beta), phosphorylated GSK-3beta, (phospho-GSK-3beta), cyclin D1, and c-myc was investigated by immunohistochemical staining on serial sections. Patients with LSTs were significantly older than those bearing PAs (63.4 vs 47.4 years old; p<0.001). The mean size of LSTs was significantly larger than that of PAs (27.0 mm vs 14.6 mm; p<0.01). Forty-eight percent of LSTs were located in the proximal colon, which was significantly higher than that of PAs (18.5%; p<0.05). Expression of beta-catenin, phospho-GSK-3beta, cyclin D1, and c-myc was significantly increased in LSTs compared with PAs (p<0.05). However, E-cadherin and total GSK-3beta expression was not significantly different between the two groups. The level of beta-catenin expression correlated strongly with phospho-GSK-3beta, cyclin D1, and c-myc expression in LSTs but not in PAs. Our findings suggest that activation of the Wnt/beta-catenin pathway is more prevalent in LSTs than in PAs, suggesting that phosphorylation-dependent inactivation of GSK-3beta may be involved in LST carcinogenesis.

Future expectations in digestive endoscopy: competition with other novel imaging techniques

Digestive endoscopy has been evolving from primary diagnostic to extensive therapeutic modalities in the management of gastrointestinal diseases. The present endoscopic imaging includes (A) standard endoscopy alone and /or with adjunct technologies such as point enhancement, e.g. confocal endomicroscopy and field enhancement technologies such as chromoendoscopy, NBI and FICE and (B) endoscopic ultrasound. Other novel imaging technologies including virtual colonoscopy or CT/MR colonography, CT or MRI enterography and capsule endoscopy have also been developed. This article reviews the diagnostic and therapeutic role of digestive endoscopy and future directions of digestive endoscopy are discussed. Digestive endoscopy is also compared with emerging novel imaging techniques in gastrointestinal diseases such as capsule endoscopy and CT colonography. The fact that digestive endoscopy has become a multidisciplinary specialty combining advances in all fields (radiology, bioengineering, surgery and gastroenterology) is highlighted.

Early Barrett's carcinoma with "low-risk" submucosal invasion: long-term results of endoscopic resection with a curative intent

BACKGROUND

Endoscopic therapy (ET) has become a less risky alternative to open surgery in mucosal Barrett's cancer (BC) because of the very low risk of lymph node (LN) metastasis. Recently published surgical series demonstrated that even in case of minimal submucosal invasion of BC, the risk for LN metastasis is very low. In consequence, also these patients might be eligible for curative ET. The aim of this study was to prospectively evaluate the efficacy and safety of endoscopic resection (ER) in these patients.

METHODS

From September 1996 to September 2003, the suspicion or definite diagnosis of submucosal BC was made in 80 patients referred to our department. Of those, 21 patients (20 male [95.2%], mean age 62 +/- 9 yr, range 47-78) fulfilled the definition of "low-risk" submucosal cancer: invasion of the upper submucosal third (sm1), absence of infiltration into lymph vessels/veins, histological grade G1/2, and macroscopic type I/II. ET was carried out using ER with the suck-and-cut technique with or without an additive ablation of non-neoplastic remnants of Barrett's esophagus.

RESULTS

One of the 21 patients was referred to surgery directly after the detection of sm1 invasion at the beginning of the study. One patient died (not tumor-related) before completion of ET. Using definitive ET, complete remission (CR) was achieved in 18 of 19 patients (95%) after a mean of 5.3 months (range 1-18) and a mean of 2.9 resections (range 1-9). Only one minor complication (bleeding without drop in hemoglobin level >2 g/dL) occurred (5% of patients). During a mean follow-up (FU) of 62 months (range 45-89), recurrent or metachronous carcinomas were found in 5 patients (28%). Repeat ET was carried out successfully using ER (4 patients) and argon plasma coagulation (1 patient). In one of the 19 patients (5%), tumor freedom had not been achieved after a total of 2 ER. This patient died of a heart attack before surgery could be performed. The calculated 5-yr survival rate of all 21 patients was 66%. No tumor-related death occurred.

CONCLUSIONS

As in mucosal BC, ER is associated with favorable outcomes even in case of "low-risk" submucosal BC. Further and larger clinical trials are required before a general recommendation for ER as the treatment of choice in "low-risk" submucosal BC can be given.

Flat and depressed types of early colorectal cancers: from East to West

Recent advances in colonoscopy have enabled us to diagnose early-stage colorectal tumors. Magnifying colonoscopy is useful for diagnosing histologic types by assessing the microstructure of the mucosal surface in detail, which also helps to predict the depth. This article describes clinicopathologic features and endoscopic treatment of flat and depressed types of early colorectal carcinoma.

Chromoscopic endomicroscopy: in vivo cellular resolution imaging of the colorectum

Advances in imaging technology and engineering have now permitted functional integration of a confocal endomicroscope into the distal tip of a conventional video colonoscope enabling imaging of the surface epithelium and the underlying lamina propria during ongoing video endoscopy. For the first time, the endoscopist is now able to resolve the surface and subsurface mucosa at cellular resolution in vivo and in real time. A new era in endoscopic imaging has therefore begun - histoendoscopy. In addition to providing a high-accuracy in vivo optical biopsy tool for the differentiation between benign hyperplasia, intra-epithelial neoplasia and carcinoma in sporadic cohorts, endomicroscopy with targeted biopsies has now been shown to increase the yield of intra-epithelial neoplasia complicating ulcerative colitis. Furthermore, recent data examining endomicroscopic molecular ex vivo imaging using anti-CD44v6 antibody has identified aberrant crypt foci based on their surface molecular expression. Receptor overexpression in vivo in humans may, in the near future, be exploited for the diagnosis of inflammation, neoplasia and in predicting targeted molecular therapy. Endomicroscopy will be key to this immuno-imaging interface. Within the present review, we discuss the current clinical evidence in support of confocal endomicroscopy and explore the new diagnostic possibilities for this technology.

Risk factors for lymph node metastasis in submucosal invasive colorectal cancer

BACKGROUND

Recent studies have shown a 7-15% lymph node (LN) metastasis rate in submucosal invasive colorectal cancer (SICC). Identifying risk factors for LN metastasis is crucial in selecting therapeutic modalities for SICC. We assessed the possibility of and the risk factors for LN metastasis in SICC.

METHODS

We performed a retrospective study on 168 SICC patients who underwent curative resection between June 1989 and December 2004 at Asan Medical Center. The level of submucosal invasion was classified into upper third (sm1), middle third (sm2), and lower third (sm3). The following carcinoma-related variables were assessed: tumor size, tumor location, depth of submucosal invasion, cell differentiation, lymphovascular invasion, neural invasion, and tumor cell dissociation (TCD).

RESULTS

The overall LN metastasis rate was 14.3%. Significant predictors of LN metastasis both univariately and multivariately were sm3 (p = 0.039), poorly differentiated cancer (p = 0.028), and TCD (p = 0.045). Lymphovascular invasion was a risk factor for LN metastasis in univariate analysis (p = 0.019); however, in multivariate analysis, lymphovascular invasion could not predict LN metastasis. No statistical difference was observed in the risk of LN metastasis with regard to tumor location, size, and neural invasion.

CONCLUSION

The depth of submucosal invasion, cell differentiation, and tumor cell dissociation were significant pathologic predictors of LN metastasis in SICC. Because SICC is associated with a considerable risk of LN metastasis, local excision may be performed carefully in SICC without adverse features.

Correlation of laterally spreading type and JC virus with methylator phenotype status in colorectal adenoma

Accurate frequencies of CpG island methylator phenotype (CIMP) have not been determined for laterally spreading tumors (LSTs) and other flat-type colorectal adenomas, and the role of JC virus T-antigen (T-Ag) in these tumors is unclear. We used MethyLight assay to analyze the relationship between CIMP status and clinicopathologic characteristics in tissue from 72 LST of granular-type (LST-G), 35 LST of nongranular-type (LST-NG), 54 protruded-type adenomas, and 89 colorectal cancers. We also investigated the relationship between CIMP status and T-Ag by immunohistochemistry. With the use of 5 markers for CIMP status, tumors were classified as CIMP-high (> or = 4/5 methylated promoters), CIMP-low (1/5 to 3/5 methylated promoters), or CIMP-0 (no methylated promoters). The proportion classified as CIMP-0 status was 5.6% for protruded-type adenoma, 17.1% for LST-NG, and 29.2% for LST-G (LST-G versus protruded-type adenoma, P = .001). CIMP-low status was established for 62.5% of LST-G, 74.3% of LST-NG, and 81.5% of protruded-type adenomas. CIMP-high status was established for 8.3% of LST-G, 8.6% of LST-NG, and 12.9% of protruded-type adenomas. The proportions of CIMP-low and CIMP-high status were not significantly different between the 3 groups. Multiple logistic analysis showed that LST-G appearance was the only significant factor for identifying CIMP-0 status. BRAF mutation was the only significant factor for identifying CIMP-high status. T-Ag expression increased with CIMP status and was not associated with macroscopic appearance. In conclusion, among colorectal adenomas, CIMP-high status was determined by BRAF mutation and not by macroscopic type, unlike CIMP-0. JC virus T-Ag may be important in determining methylator phenotype.

Endoscopic treatment of colorectal neoplasms: a simple and safe procedure to lower the incidence of colorectal cancers

AIM

For many physicians who ordinarily treat patients with colonic diseases, colonoscopy is considered a prime study interest. Developments in colonoscopic equipment and methods have led to larger numbers of endoscopic diagnoses and treatments for colorectal neoplasms. The purpose of this investigation is to evaluate the efficacy and outcomes of endoscopic treatment for colorectal neoplastic lesions and the development of colorectal cancers after colonoscopic therapy.

MATERIALS AND METHODS

From September 1999 to May 2005, 19,815 consecutive colonoscopic examinations in 16,318 patients were gathered, totaling 9,534 endoscopic treatments for colorectal neoplasms. Macroscopic characteristics of the neoplasms were classified into protruded (N = 7,455), sessile (N = 1,569), lateral spreading tumor (N = 201), depressed lesions (N = 21), and flat lesions (N = 288). Snare polypectomy was conducted in 7,536 lesions, hot forceps removal in 1,545 lesions, and endoscopic mucosal resection in 353 lesions.

RESULTS

Histological diagnoses were 8,333 neoplastic lesions (8,246 adenomas with low/high-grade dysplasia and 87 invasive adenocarcinomas) and 1,201 non-neoplastic lesions (1,186 hyperplastic and 15 inflammatory polyps). For the adenocarcinoma group, all had received further operations, while 73 surgical specimens discovered no residual tumors. Four perforations and 146 bleedings were found following endoscopic treatment. No procedure-related mortality was found and no recurrent malignancy was found after 6-71 months follow-up.

CONCLUSION

To lower the incidence and mortality of advanced colorectal cancer, endoscopic treatment for colorectal neoplasms is a simple and safe procedure.

Management of early rectal cancer

BACKGROUND

Early rectal cancer (ERC) is adenocarcinoma that has invaded into, but not extended beyond, the submucosa of the rectum (that is a T1 tumour). Local excision is curative for low-risk ERCs but for high-risk cancers such management is controversial.

METHODS

This review is based on published literature obtained by searching the PubMed and Cochrane databases, and the bibliographies of extracted articles.

RESULTS AND CONCLUSION

ERC presents as a focus of malignancy within an adenoma, as a polyp, or as a small ulcerating adenocarcinoma. Preoperative staging relies on endorectal ultrasonography and magnetic resonance imaging. Pathological staging uses the Haggitt and Kikuchi classifications for adenocarcinoma in pedunculated and sessile polyps respectively. Lymph node metastases increase with the Kikuchi level, with a 1-3 per cent risk for submucosal layer (Sm) 1, 8 per cent for Sm2 and 23 per cent for Sm3 lesions. Low-risk ERCs may be treated endoscopically or by a transanal procedure. Transanal excision or transanal endoscopic microsurgery may be inadequate for high-risk ERCs and adjuvant chemoradiotherapy may be appropriate. There is a low rate of recurrence after local surgery for low-risk ERCs but this increases to up to 29 per cent for high-risk cancers.

Endoscopic mucosal resection in the upper gastrointestinal tract

Endoscopic mucosal resection (EMR) is a technique used to locally excise lesions confined to the mucosa. Its main role is the treatment of advanced dysplasia and early gastrointestinal cancers. EMR was originally described as a therapy for early gastric cancer. Recently its use has expanded as a therapeutic option for ampullary masses, colorectal cancer, and large colorectal polyps. In the Western world, the predominant indication for EMR in the upper gastrointestinal tract is the staging and treatment of advance dysplasia and early neoplasia in Barrett’s esophagus. This review will describe the basis, indications, techniques, and complications of EMR, and its role in the management of Barrett’s esophagus.

A case of advanced colonic cancer that developed from residual laterally spreading tumor treated by piecemeal endoscopic mucosal resection

This case report showed a laterally spreading tumor treated by endoscopic mucosal resection that developed as an advanced colon cancer. A 74-year-old female was visited to treat a colon tumor that was pointed out at another hospital. Total colonoscopy revealed a laterally spreading tumor (LST) 25 mm in diameter in the cecum. The lesion was diagnosed as homogenous granular type LST (G-type LST) and treated by endoscopic piecemeal mucosal resection in January 2004. A tumor was recognized by follow-up endoscopic examination in April 2006. The scar of endoscopic piecemeal mucosal resection had developed to advanced colon cancer and was treated by laparoscopy-associated ileocecal resection with D3 lymph node resection. Previous reports indicated that G-type LST in the colon could be treated by piecemeal resection, but this report suggests that G-type LST resected by piecemeal endoscopic mucosal resection might develop to advanced colon cancer.

In vivo confocal laser scanning chromo-endomicroscopy of colorectal neoplasia: changing the technological paradigm

Recently, miniaturization of a novel confocal laser endomicroscope (Optiscan Pty, Notting Hill, Victoria, Australia) has permitted functional integration into the distal tip of a conventional video colonoscope (Pentax EC3870K; Pentax, Tokyo, Japan) enabling imaging of the surface epithelium and the underlying lamina propria during ongoing video endoscopy. Using endomicroscopy and intravenous sodium fluorescein as a contrast agent, 'virtual histology' can be created, which allows visualization of both the surface epithelium, and some of the lamina propria (down to a quarter of a millimetre), including the microvasculature. Confocal endomicroscopy may have major implications in the future of colonoscopy as uniquely it allows in vivo diagnosis of colonic intraepithelial neoplasia and carcinoma enabling 'smart' biopsy targeting and hence potentially influencing 'on table' management decisions. Initial pilot data have now shown that confocal imaging in vivo using the newly developed EC3870K has high overall accuracy for the immediate diagnosis of intraepithelial neoplasia and carcinoma in sporadic screened cohorts, but also has a role in the detection of intraepithelial neoplasia detection in chronic ulcerative colitis cancer screening when used in conjunction with methylene blue chromoscopy. We discuss the current evidence in support of confocal endomicroscopy in the colorectum and explore the new diagnostic possibilities for this technology.

Establishment and characterization of a new cell line derived from human colorectal laterally spreading tumor

AIM: To study the molecular mechanism of laterally spreading tumor (LST), a cell line [Laterally Spreading Tumor-Rectum 1 (LST-R1)] was derived and the characteristics of this cell line were investigated.

METHODS: A new cell line (LST-R1) originated from laterally spreading tumor was established. Properties of the cell line were characterized using scanning and transmission electron microscopy, immunohistochemistry method, cytogenetic analysis and nude mice xenograft experiments. In vitro invasion assay, cDNA microarray and Western blotting were used to compare the difference between the LST-R1 and other colorectal cancer cell lines derived from prudent colon cancer.

RESULTS: Our study demonstrated that both epithelial special antigen (ESA) and cytokeratin-20 (CK20) were expressed in LST-R1. The cells presented microvilli and tight junction with large nuclei. The karyotypic analysis showed hyperdiploid features with structural chromosome aberrations. The in vivo tumorigenicity was also demonstrated in nude mice xenograft experiments. The invasion assay suggested this cell line has a higher invasive ability. cDNA microarray and Western blotting show the loss of the expression of E-cadherin in LST-R1 cells.

CONCLUSION: We established and characterized a colorectal cancer cell line, LST-R1 and LST-R1 has an obvious malignant tendency, which maybe partially attributed to the changes of the expression of some adhesion molecules, such as E-cadherin. It is also a versatile tool for exploring the original and progressive mechanisms of laterally spreading tumor and the early colon cancer genesis.

Hypermethylation status of APC inversely correlates with the presence of submucosal invasion in laterally spreading colorectal tumors

Little is known about epigenetic alterations in laterally spreading colorectal tumors (LSTs). The goal of the present study was to elucidate the epigenetic background of LSTs and compare the methylation status of DNA CpG islands (CGIs) with clinicopathologic features. Methylation of MINT1, MINT2, MINT31, p16, O(6)-methylguanine-DNA methyltransferase (MGMT), adenomatous polyposis coli (APC), and human MutL homologue 1 (hMLH1) in 42 LSTs was assessed by methylation-specific polymerase chain reaction (MSP) and compared with clinicopathologic parameters. The frequency of hypermethylation was 12.5% (4/32) for MINT1, 40.0% (16/40) for MINT2, 25.0% (10/40) for MINT31, 25.7% (9/35) for p16, 7.7% (3/39) for hMLH1, 26.5% (9/34) for MGMT, and 35.9% (14/39) for APC. APC methylation was inversely associated with submucosal invasion (P = 0.034), which was not found in any of 14 LST cases with APC methylation, whereas submucosal invasion was present in 8 of 25 (32.0%) cases without APC methylation. These data suggest that hypermethylation of APC could be a predictive marker for the absence of submucosal invasion of LSTs.

Clinicopathologic characteristics and malignant potential of colorectal flat neoplasia compared with that of polypoid neoplasia

PURPOSE

Because of their potential for malignancy, flat colorectal neoplasias are a current topic of debate. This study was designed to investigate the clinicopathologic features of flat neoplasia and to compare them with those of polypoid neoplasia, as well as to identify the determinants of malignant transformation of both flat and polypoid colorectal neoplasia.

METHODS

A prospective, cross-sectional study of 3,360 patients diagnosed with adenomas via total colonoscopy and polypectomy was performed at 11 tertiary medical centers between July 2003 and July 2004. In this study, potential risk factors for malignant transformation were analyzed. If multiple adenomas were identified, then only the adenoma with the most advanced degree of histology was recorded for the patient.

RESULTS

Of a total of 3,360 neoplasias identified, we found that the incidence of flat and polypoid neoplasias were 207 (6.2 percent) and 3,153 (93.8 percent), respectively. Patients with flat neoplasias tended to be older (59.6 vs. 57.1, P < 0.01), with the neoplasia located more frequently in the right colon than polypoid neoplasias (49.3 percent vs. 32 percent, P < 0.01). The incidence of high-grade dysplasia or cancer in flat neoplasias was similar to that of polypoid neoplasias (5.4 percent vs. 4.6 percent, P = 0.36). Multivariate analysis revealed that a size of > or =11 mm (odds ratio, 6.8; 95 percent confidence interval, 4.8-9.7) and location in the left colon (odds ratio, 1.6; 95 percent confidence interval, 1.1-2.4) were significant determinants for the malignancy potential of colonic neoplasias.

CONCLUSIONS

The clinicopathologic indices for the propensity of malignant transformation in colorectal neoplasias were a size > or =11 mm and location in the left colon rather than flat gross morphology.

Relationship of BRAF mutation, morphology, and apoptosis in early colorectal cancer

BACKGROUND AND AIMS

Many investigators have reported flat and depressed lesions as a new type of precursor of colorectal cancer. In our previous study, we determined that mutations in the BRAF gene may contribute to colorectal carcinogenesis by inhibiting apoptosis. However, the relationship among BRAF mutations, morphology and apoptosis in early colorectal cancer has not been clear. Therefore, gene alternation, morphology, and apoptosis in early colorectal cancer were investigated.

MATERIALS AND METHODS

Forty-five flat and depressed early colorectal cancer samples and 43 polypoid early colorectal cancer samples were analyzed. Mutations in the BRAF gene and the K-ras gene were examined by direct sequence analysis, and proliferative activity and induction of apoptosis were evaluated using immunohistochemical examination. RESULTS FINDINGS: BRAF mutations were found in 5 (11.1%) of 45 flat and depressed early colorectal cancer samples. No BRAF alteration was found in polypoid early colorectal cancer samples. Mutations in the K-ras gene were detected in 13 (30.2%) of 43 polypoid early colorectal cancer samples. The rate of submucosal invasion of the samples with BRAF mutations was significantly higher than that of the samples with K-ras mutations (p<0.05).

INTERPRETATION/CONCLUSIONS

BRAF and K-ras mutations were independent factors that influenced morphology in early colorectal cancer. In this study, the relationship between BRAF mutation and apoptosis is not so clear, but BRAF mutations and inhibition in apoptosis may play an important role in the developmental process of flat and depressed early colorectal cancer.

Prolongation of the period between biopsy and EMR can influence the nonlifting sign in endoscopically resectable colorectal cancers

BACKGROUND

The nonlifting sign is widely used for evaluating the invasion depth of colorectal tumors, and it is commonly accepted that EMR is contraindicated for colorectal tumors with a nonlifting sign because of the probability of massive submucosal invasion.

OBJECTIVE

To identify the clinicopathologic factors that affect the nonlifting sign in submucosal invasive colorectal carcinoma (SICC).

DESIGN

Details regarding a history of biopsy, postbiopsy days, tumor location, tumor configuration, tumor size, depth of submucosal invasion, histologic type, adenomatous remnants, and angiolymphatic invasion were studied in relation to the nonlifting sign.

SETTING

National Cancer Center, Korea.

PATIENTS

The study involved 76 patients with SICC treated by endoscopic or surgical resection, in whom the tumor was examined for the nonlifting sign from 2001 to 2006.

RESULTS

The nonlifting sign was observed in 15 cases (19.7%). A deep submucosal invasion, a history of biopsy, and the absence of adenomatous remnants were identified as factors affecting the nonlifting sign in univariate and multivariate analyses (P < .05). An increase in the number of postbiopsy days was associated with the nonlifting sign in endoscopically resectable SICC, and all 11 sm1 cancer cases with fewer than 21 postbiopsy days showed lifting.

CONCLUSIONS

A history of biopsy and the absence of adenomatous remnants, in addition to deep submucosal invasion, were found to influence the nonlifting sign in SICC. It may be best that mechanical stimulation such as forceps biopsies are minimized before EMR, and EMR should be tried as soon as possible if biopsy was performed.

The lymphatic infiltration identified by D2-40 monoclonal antibody predicts lymph node metastasis in submucosal invasive colorectal cancer

BACKGROUND AND STUDY AIMS

Lymphatic infiltration has been recognized as a significant risk factor for lymph node metastasis of submucosal invasive colorectal cancer (SICC), but it is difficult to detect microscopically on hematoxylin and eosin (H&E)-stained slides. We therefore identified lymphatic infiltration of tumor cells with D2-40 monoclonal antibody, which reacts specifically against the endothelium of lymphatic vessels, to make an objective and precise diagnosis.

PATIENTS AND METHODS

The surgical specimens of 122 consecutive patients with nonpedunculated SICC were examined for lymphatic infiltration by immunohistochemical staining with D2-40 monoclonal antibody (LI-D) and for venous infiltration by Elastica van Gieson staining (VI-E).

RESULTS

Lymph node metastasis was found in 20 patients. Multivariate analysis showed that LI-D (p = 0.0415) and VI-E (p = 0.0119) were significant risk factors for lymph node metastasis. Regardless of the presence of risk factors including at least either lymphatic infiltration or venous infiltration, no lymph node metastasis-positive patients were found (0%) among the 25 patients whose colorectal cancer had a submucosal invasive depth of less than 1,500 microm. No lymph node metastasis was found in any of the patients with a depth of submucosal invasion of less than 3,000 microm, who had no risk factors, including LI-D or VI-E.

CONCLUSIONS

Correct evaluation of lymphatic infiltration by immunohistochemical staining with D2-40 monoclonal antibody may play a crucial role in determining whether there are indications for additional treatment in the management of endoscopically resected SICC.

Magnifying colonoscopy: interobserver agreement in the assessment of colonic pit patterns and its correlation with histopathological findings

BACKGROUND AND STUDY AIMS

Magnifying colonoscopy (MC) is recognized as an aid to the differential diagnosis between neoplastic and nonneoplastic lesions. This study evaluated interobserver agreement of experienced endoscopists in the assessment of colonic pit patterns through the Kudo's classification and correlated morphological aspects with histopathological findings.

MATERIALS AND METHODS

A total of 213 magnification chromoendoscopic pictures of colonic lesions were collected from 161 consecutive patients and presented to three independent observers who expressed opinion about predominant pit pattern. All lesions were excised and sent for histopathological study.

RESULTS

Kappa statistics showed that the general agreement index with respect to the aspects of the pits was good among the three observers (0.561). Regarding prediction of histopathology according to the pit pattern diagnosis, overall accuracy was 84%, sensitivity was 91.4%, specificity was 67.2%, positive predictive value was 86.6%, and negative predictive value was 79.3%.

CONCLUSION

Although the interobserver reproducibility of the colonic pit pattern is good for experienced endoscopists, MC must not be used to replace the histopathological analysis, since it does not differentiate with the necessary safety neoplastic from nonneoplastic lesions.