This document discusses the treatment of large sessile colon polyps (LSTs) and the challenges of differentiating between benign and cancerous lesions. It notes that endoscopic mucosal resection (EMR) is usually used but has limitations, while endoscopic submucosal dissection (ESD) enables complete removal and better histological assessment. ESD may avoid unnecessary surgery for lesions with superficial submucosal cancer invasion that can be cured endoscopically. The document reviews different classification systems to predict cancer risk but notes limitations. It advocates that ESD skills and adoption continue improving to help incorporate it more into clinical practice for treating difficult colon polyps.

1. Kurdistan Board GEH/GIT Surgery J Club 2022
Supervised by Professor Dr. Mohamed Alshekhani.

2. Introduction:
 LSTs are increasingly encountered with the uptake of CRC screening
 The approach to LSTs is determined by the risk of submucosal invasive
cancer (SMIC), because this dictates the most appropriate endoscopic or
surgical intervention.
 Endoscopic mucosal resection (EMR) is the first-line treatment for LSTs
without SMIC, given its cost-effectiveness, superior safety profile&patient
quality of life compared with surgery.
 LSTs with SMIC have been traditionally referred for surgery.
 More recently, ESD, has emerged as a minimally invasive alternative to
surgery for LSTs with superficial SMIC.
 ESD enables the en bloc resection of lesions irrespective of size, which
confers 2 distinct advantages:
 Ideal specimen for accurate histologic assessment.
 Low risk for recurrence.

6. LSD:Classification&SMIC chalanges
 Polyp morphology can help predict the risk of SMIC.
 Several classification systems;Kudo&Japanese NBI Expert Team (JNET),
are routinely used in Japan for lesion assessment before resection.
 Despite their accuracy in predicting SMIC, implementation limited by
complexity&need of high magnification endoscopy, not widely available.
 NBI international colorectal endoscopic (NICE) classification system is
potentially more pragmatic for polyp categorization without magnification
or dye spray,but not been widely adopted in everyday routine clin practice.
 The fact that multiple biopsies or even partial resection of LSTs for
histologic diagnosis remain a common practice suggests that we have yet to
embrace real-time optical diagnosis in the evaluation of colorectal lesions.
 The main limitation of all of these classification systems is their inability to
reliably distinguish benign neoplastic CR polyps containing HGD from
superficial SMIC.

7. LSD:Classification&SMIC chalanges
 This limitation is inherent to the NICE classification where high-grade
dysplasia &superficial SMIC are grouped under the same category (NICE
type 2).
 Lesions with suspected superficial SMIC should be resected en bloc for
precise histopathologic assessment for curative intent.
 Piecemeal EMR of lesions with suspected superficial SMIC leads to
pathologic uncertainty & unnecessary surgery for otherwise
endoscopically curable lesions,which can be devastating for patients,
particularly in the rectum, where post-endoscopic surgery is associated
with poor QOL.

8. Colonic ESD:
 Colorectal ESD has long supplanted EMR as the preferred endoscopic
resection strategy in Japan for various factors:
 The well-recognized inability to reliably identify superficial SMIC.
 The widely available ESD expertise
 Other inherent advantages of ESD(accurate histopathology, low
recurrence & ability to provide cure for selected SMICs).
 Western proponents of EMR over ESD:
 Most LSTs are benign.
 Subset that contain SMIC (10%G -32% NG)that require ESD is low.
 Can be adequately removed with piecemeal resection
 The true prevalence of SMIC in many studies may be underrepresented,
because final histologic diagnoses were primarily based on piecemeal EMR
rather than ESD or surgery,so subset of LSTs for which ESD offers a
reasonable higher chance of avoiding surgery may be higher than
anticipated.

9. Colonic ESD:
 Recent promising advances in EMR as thermal trt of EMR defect margins,
but:
 Recurrence after EMR remains a clinical concern in clinical practice.
 Incomplete EMR often entails more frequent colonoscopies, inconvenient
bowel preparation&time off work for patients, all with clearly adverse
financial / psychosocial implications.
 Although most benign recurrences can be adequately managed
endoscopically, a small subset of patients may still end up requiring
surgery for either benign recurrences no longer amenable to endoscopic
treatment or even more concerning,invasive&metastatic recurrence.
 Long-term surveillance&loss follow-up.
 Medolegal concerns.
 ESD does not adversely affect long-term oncologic outcomes following
secondary surgery for noncurative resection.
 Not all patients with endoscopic R1 resection of T1 colorectal cancer
require secondary surgery.

10. Improving skills in ESD:
 Visiting&observing Japanese ESD masters.
 Complementary skill acquisition via self-directed didactics & training on
animal models.
 The expanding array of traction devices available.
 The introduction of different colorectal ESD techniques (eg, submucosal
tunneling, pocket creation method, hybrid ESD) have helped flatten the
learning curve of colorectal ESD.

12. Conclusion:
 Making the distinction between benign LSTs versus&SMIC on real-time
optical diagnosis remains a clinical challenge.
 Colorectal ESD may be a suitable initial approach for lesions with
suspected SMIC, because it can be curative for selected superficial cancers
yet without compromising outcomes for those who may require secondary
surgery for deep invasion.
 ESD also represents a viable alternative to lesions not amenable to EMR,
which should help curtail the need for unnecessary surgery.
 Although technical demand& lack of proper reimbursement are current
challenges to ESD, the increasing availability of local ESD mentors,
training pathways&dedicated devices have led to its adoption in many
tertiary centers & should continue to facilitate its ongoing incorporation
into mainstream endoscopic practice.