Endoscopic submucosal dissection (ESD) for colorectal tumors

Learning curve associated with colorectal endoscopic submucosal dissection for endoscopists experienced in gastric endoscopic submucosal dissection

BACKGROUND

Colorectal endoscopic submucosal dissection requires a high level of skill and experience in therapeutic endoscopy because of the high risk of complications such as perforation and bleeding. Greater understanding of the procedural learning curve is required to standardize training and to achieve wider acceptance of this procedure.

OBJECTIVE

The aims of this study were to evaluate the clinical outcomes of colorectal endoscopic submucosal dissection and to clarify its learning curve for endoscopists.

DESIGN

We retrospectively reviewed the clinical outcomes for consecutive patients with colorectal neoplasms who underwent endoscopic submucosal dissection by 2 trainees under the guidance of experienced specialists.

SETTING

The study was performed at the National Cancer Center Hospital, Tokyo, Japan.

PATIENTS

Colorectal endoscopic submucosal dissections were performed for 101 consecutive patients with 102 colorectal neoplasms between April 2008 and December 2010.

MAIN OUTCOME MEASURES

Procedure time, en bloc resection rate, completion rate, and complications were retrospectively compared between 4 training periods in which each trainee performed 10 endoscopic submucosal dissections per period and a final training period in which the trainees performed 10 to 12 endoscopic submucosal dissections to analyze the skill improvement with time.

RESULTS

The procedure time and en bloc resection rate were not significantly different among the training periods. However, the completion rates in the fourth (100%) and fifth (95.5%) training periods (≥ 31 cases/trainee) were significantly higher (P < .001) than those in the first (45%), second (70%), and third (80%) training periods (1-30 cases/trainee). Two cases of perforation occurred during the study.

LIMITATIONS

Limitations include the single-center design. Training programs and instruments vary with institution, which could affect the learning curve.

CONCLUSIONS

Trainee endoscopists are able to perform colorectal endoscopic submucosal dissection without serious complications under the guidance of experienced specialists. They can perform it safely and independently after preparatory training and experience with ≥ 30 cases.

Risk factors for unfavorable outcomes after endoscopic removal of submucosal invasive colorectal tumors

BACKGROUND & AIMS

Oncologic surgery is recommended after endoscopic resection of submucosal invasive T1 colorectal carcinomas if patients are considered to be at high risk for tumor recurrence or metastasis. However, there are sparse data on the outcome of high-risk patients treated only by endoscopy.

METHODS

Data were collected from 474 patients who underwent endoscopic resection for T1 colorectal cancers from 1974-2002 at Neuperlach Hospital in Munich, Germany. Patient files were reviewed, and patients or referring physicians were contacted to assess outcomes during a follow-up period of at least 24 months (n = 390). Histopathology and endoscopy factors associated with an unfavorable outcome (local recurrence of tumors, metastasis, or death from colorectal cancer) were assessed.

RESULTS

Of the 390 patients followed, 141 received oncologic surgery, and 249 did not; overall, 10% had an unfavorable outcome (39/390). Multivariate regression analysis revealed that lymphatic vessel infiltration, poor grading of tumor stage, and incomplete endoscopic resection were risk factors for unfavorable outcomes (odds ratios, 7.8, 3.4, and 2.6, respectively). If these risk factors were applied to patients who did not receive oncologic surgery, negative predictive values for an unfavorable outcome were 94.6% for lymphatic vessel infiltration, 94.2% for poor grading of tumor stage, and 96.5% for incomplete endoscopic resection; positive predictive values were 44.4%, 42.9%, and 19.6%, respectively.

CONCLUSIONS

Tumor infiltration of lymphatic vessels is the greatest risk factor for an unfavorable outcome after endoscopic resection for colorectal carcinoma. However, its positive predictive value is low. The decision to perform surgery after endoscopic resection of T1 colorectal cancers should be made on the basis of specific features of each patient.

[Colorectal adenoma: pro conventional/laparoscopic resection]

The knowledge that due to the adenoma-cancer sequence polyps will develop sooner or later into invasive cancer demands the complete removal of colorectal polyps. The majority of polyps can be endoscopically removed. The indications for surgical removal of polyps are a previous incomplete endoscopic resection, location not amenable to endoscopic removal and lesions which are macroscopically highly suspicious for malignancy and cannot be detached by submucosal saline injection. If a surgical approach is indicated minimally invasive surgery in the hands of an experienced laparoscopic surgeon is a suitable option. Adenomas suspicious for malignancy in the lower two thirds of the rectum should not be treated by time-consuming endoscopic submucosal dissection (ESD) and can be quickly and safely removed transanally, conventionally or by transanal endoscopic microsurgery (TEM) by a full thickness én bloc resection. This allows the pathologist to determine the depth of invasion and the completeness of resection in terms of the circumferential margin and a definitive radical surgical approach is only necessary in high risk situations.

Endoscopic colorectal imaging and therapy

PURPOSE OF REVIEW

Colorectal cancer screening and prevention is a pivotal element in every gastroenterologist practice. Recent advances in imaging technology and treatment opened the field for endoscopic management of large flat colorectal polyps and early cancer.

RECENT FINDINGS

High-definition white light colonoscopy allowed for better characterization of colon polyps, particularly flat lesions. Chromoendoscopy facilitated the identification of colon polyps as well as better endoscopic polyp characterization, with strong correlation with final pathological diagnosis, opening the field of 'virtual' biopsy. One particular technology, confocal endomicroscopy can magnify an image approximately 1000 times resembling optical microscopy with very good correlation with histology. Endoscopic mucosal resection has gained great acceptance to manage flat colorectal polyps with the two major complications being bleeding and perforation, both now under 5% in experienced hands. Endoscopic submucosal resection was developed to increase en-bloc resection (less residual disease) of a flat colorectal lesion but one has to accept a higher perforation rate around 10%.

SUMMARY

Current technology allows for better polyp identification and characterization, which can be managed endoscopically.

The target sign: an endoscopic marker for the resection of the muscularis propria and potential perforation during colonic endoscopic mucosal resection

BACKGROUND

EMR of large sessile polyps and laterally spreading tumors (LSTs) of the colon is safe and cost-effective. Perforation remains a feared and well-recognized complication; however, endoscopic detection is often absent, and most commonly, diagnosis is delayed and depends on clinical signs and/or radiology findings. To date, an endoscopic sign to identify muscularis propria (MP) resection and potential perforation has not been described.

OBJECTIVE

To describe an endoscopic sign for prompt recognition of EMR-related MP resection.

DESIGN

Prospective analysis.

SETTINGS

Tertiary referral academic gastroenterology unit.

PATIENTS

Patients with the target sign were identified prospectively in 2 large prospective studies of EMR for colonic LSTs 20 mm or larger.

INTERVENTION

A standardized EMR approach was used. MP defects were closed endoscopically with clips.

MAIN OUTCOME MEASUREMENTS

The presence or absence of the target sign in the polypectomy specimen and its influence on subsequent endoscopic management of polypectomy complications.

RESULTS

A total of 445 patients with LSTs or sessile polyps 20 mm or larger (mean size 33 mm, range 20-85 mm) were prospectively enrolled in 2 studies. Ten patients (mean age 70.3 years, range 48-83 years, 50% male) with target lesions and histologically confirmed MP resection were identified prospectively at the time of EMR, with 3 having full-thickness resection. All cases were identified intraprocedurally by a target sign on the underside of the specimen and a mirror target evident in the mucosal defect. All patients were treated endoscopically with 1 to 5 endoscopic clips. None required operative management. Thirteen inpatient days were required to treat the 10 patients (mean 1.3 days).

LIMITATIONS

Nonrandomized study.

CONCLUSIONS

Careful analysis of the post-EMR specimen and resection defect may reveal a target sign, an easily recognized and reliable marker of either partial- or full-thickness MP resection and potential perforation. Prompt recognition of this sign facilitates endoscopic management.

Learning curve for endoscopic submucosal dissection of large colorectal tumors

BACKGROUND AND AIM

No studies have previously described the learning curve for colonic endoscopic submucosal dissection (ESD). The aim of the present study was to describe the learning curve for ESD of large colorectal tumors based on a single colonoscopist's experience.

METHODS

ESD was carried out for 120 colorectal tumors in 115 patients (68 males, median age 70 years). All procedures were carried out by a single experienced colonoscopist. The cases were grouped chronologically into three periods: (1st): cases 1-40; (2nd): cases 41-80; and (3rd): cases 81-120.

RESULTS

The learning curve was the changes in proficiency over time. Proficiency was expressed as procedure time per unit area of specimen. In the 1st, 2nd and 3rd periods, the proficiencies were 18.9, 12.6 and 12.9 (min/cm(2) ), respectively. The proficiencies in the 2nd and 3rd periods were significantly shorter than in the 1st period (t-test, P < 0.05). The en-bloc resection rates of the 1st, 2nd and 3rd periods were 92.5% (37/40), 90% (36/40) and 97.5% (39/40), respectively. The en-bloc and R0 resection rates of the 1st, 2nd and 3rd periods were 85% (34/40), 77.5% (31/40) and 92.5% (37/40), respectively. The perforation rates of the 1st, 2nd and 3rd periods were 12.5% (5/40), 5% (2/40) and 5% (2/40), respectively.

CONCLUSION

Based on our analysis of the learning curve, approximately 80 procedures must be carried out to acquire skill with ESD for large colorectal tumors. However, approximately 40 procedures were sufficient to acquire skill in avoiding perforations during the ESD procedure.

Endoscopic mucosal resection and endoscopic submucosal dissection in esophageal and gastric cancers

PURPOSE OF REVIEW

To summarize the literature to date on endoscopic mucosal removal techniques as applied to the upper gastrointestinal tract, predominantly the stomach and esophagus. This is an area that has rapidly advanced in terms of new procedures and techniques with a large body of outcomes that support their use.

RECENT FINDINGS

The resection techniques can be divided into two forms, mucosal resection and submucosal dissection. Mucosal resection is typically done with cap techniques and is more suitable for removable of neoplastic lesions that are less than 1.5 cm in size. Submucosal dissection techniques are more difficult, associated with increased complications, and typically reserved for lesions greater than 1.5 cm and less than 3 cm in size. Ideal lesions for mucosal resection are generally flat and are located in areas easily accessible by the endoscope.

SUMMARY

Endoscopic tissue removal methods are capable of removing neoplastic lesions en bloc in the upper gastrointestinal tract. These techniques fulfill cancer treatment guidelines by having histological confirmation of total removal of neoplastic lesions with assessment of the margins of resections. Long-term clinical outcomes of these techniques are emerging and seem promising in terms of disease-free and overall survival.

Dynamic submucosal injection technique

This article describes the submucosal injection technique applied in the endoscopic resection of non-polypoid colorectal neoplasms, with an emphasis on a particular technique, the dynamic submucosal injection technique.

Local recurrence and surveillance after endoscopic resection of large colorectal tumors

Local recurrence rates after endoscopic piecemeal mucosal resection (EPMR) typically range from 10 to 23%. In our previous study, the local recurrence rate after a piecemeal resection was significantly higher than that after an en bloc resection, irrespective of tumor size or macroscopic features. To reduce local recurrence after an EPMR, it is important to carefully note the circumferences of the edge and base of the ulcer. Recently, endoscopic submucosal dissection (ESD) was developed and recognized for its effectiveness in large, complete, en bloc resections and precise pathological assessments. ESD also showed lower local recurrence rates, ranging from 0 to 3% in previous, retrospective studies. However, ESD showed a higher perforation rate and longer procedure times; thus, it is necessary to improve ESD. An appropriate surveillance interval after EPMR was still controversial, and recommendations of some guidelines ranged from 2 to 9 months. In order to determine the appropriate interval, a randomized controlled study is necessary.

Indications for endoscopic resection of colorectal polyps and surveillance guidelines

We report three keynote lecture presentations from the Endoscopic Forum Japan 2009 at Otaru, Hokkaido, on 1-2 August 2009. We will discuss herein: (i) colorectal cancer screening focusing on a comparison between the National Polyp Study and the Japan Polyp Study; (ii) how to deal with small polyps <5 mm in diameter; (iii) the natural history of colorectal tumor development; (iv) the importance of follow up for local recurrence after endoscopic resection for colorectal polyps; and (v) screening for colorectal cancer using two new modalities, narrow-band imaging and autofluorescence imaging. A questionnaire was completed by everyone involved in the conference and the most important results were reported and then discussed by the participants.

Perspectives on the treatment of colorectal carcinoma

Colorectal cancer includes cancerous growths in the colon, rectum and appendix. With 655000 deaths worldwide per year, it is the third most common form of cancer and the second leading cause of cancer-related death in the Western world. Advances in imaging, genetics, molecular diagnostics, surgical techniques and chemotherapy are now making significant gains in our ability to prevent, diagnose, and treat this serious disease. This article reviews some of these recent successes and shares a vision of future care based on current research.