Should ESD be performed or referral considered for a rectal polyp with high malignancy risk based on JNET, KUDO, and CONNECT classifications?

Management of Rectal Polyp with High Malignancy Risk Based on JNET, KUDO, and CONNECT Classifications

For a rectal polyp showing high-risk features on JNET Type 3, KUDO Type V (VN or VI), or concerning CONNECT patterns, you should NOT attempt endoscopic resection if the lesion is non-pedunculated—instead, biopsy the area of surface disruption, tattoo the site (unless near the cecum), and refer directly to a colorectal surgeon. 1 However, if the lesion is pedunculated with these features, proceed with endoscopic polypectomy. 1

Understanding the Classification Systems and Risk Stratification

High-Risk Endoscopic Features Predicting Deep Submucosal Invasion

The following features indicate deep submucosal invasion with high specificity:

• JNET Type 3: Characterized by loose vessel areas with interruption of thick vessels, and amorphous surface areas—this predicts deep submucosal invasive cancer 1
• KUDO Type V: Specifically VN (loss or decrease of pits with amorphous structure) and VI (irregular arrangements and sizes of pits) patterns indicate deep invasion 1
• NICE 3 features: Any one of three features (abnormal color, disrupted vessels, or amorphous surface pattern) has 94% accuracy and 96% negative predictive value for deep submucosal invasion 1

Additional concerning morphologic features include:

• Paris 0-IIc morphology (depressed component) 1, 2
• Dark brown coloration with areas of disrupted or missing vessels 1
• Non-granular surface morphology, particularly in rectosigmoid location 2

Decision Algorithm Based on Polyp Morphology

For Non-Pedunculated (Sessile or Flat) Lesions

When you identify JNET Type 3, KUDO Type V, or NICE 3 features:

1. Perform limited cold forceps biopsy only in the area of surface feature disruption to confirm histology 1
2. Tattoo the lesion at 2-3 separate locations, 3-5 cm distal to the polyp (unless in cecum or near anal verge) 1
3. Refer directly to colorectal surgery—do NOT attempt endoscopic resection 1

Critical pitfall to avoid: Excessive cold biopsy forceps tissue sampling or partial snare resection promotes scarring and fibrosis that makes subsequent curative resection more difficult 1

For Pedunculated Lesions

Even with high-risk features, pedunculated polyps should undergo endoscopic polypectomy because:

• The stalk allows assessment of invasion depth using Haggitt classification 1
• En-bloc resection provides intact specimen for accurate pathologic assessment 1
• Hot snare polypectomy is recommended for pedunculated lesions >10 mm 3

After resection, histologic evaluation determines need for surgical resection based on:

• Depth of submucosal invasion (>1000 μm requires surgery) 1
• Presence of lymphovascular invasion 1
• Poor differentiation 1
• Positive margins 1

When ESD Might Be Considered (Requires Advanced Endoscopist)

ESD should only be performed by experienced endoscopists and is appropriate for:

• T1 rectal cancers with superficial submucosal invasion (<1000 μm predicted) 1
• Large complex polyps requiring en-bloc resection where EMR would result in piecemeal removal 1
• Lesions without NICE 3 or KUDO V features but requiring complete resection 1

ESD advantages in the rectum specifically:

• The rectum is below the peritoneal reflection, making ESD technically less challenging and safer than in other colon segments 1
• En-bloc resection rates of 88.8% with R0 resection in 85.6% of cases 1
• Curative resection achieved in 79.8% of rectal lesions 1
• Low adverse event rate (5.9%) with no patients requiring surgery for complications 1

Risk Factors for Covert Malignancy

Even without obvious high-risk features, certain characteristics increase covert submucosal invasive cancer risk:

• Rectosigmoid location (odds ratio 1.87) 2
• Non-granular surface morphology (odds ratio 3.96-22.5) 2
• Combined Paris classification (0-Is or 0-IIa+Is) 2
• Increasing size (odds ratio 1.16 per 10 mm increase) 2

Rectosigmoid 0-Is and 0-IIa+Is non-granular lesions have particularly high malignancy risk and warrant referral to an advanced endoscopist or consideration for surgical evaluation. 2

Histologic Criteria for Curative Endoscopic Resection

If endoscopic resection is performed, curative resection requires ALL of the following:

• En-bloc resection with negative horizontal and vertical margins 1
• Submucosal invasion <1000 μm (SM1 level) 1
• Well to moderately differentiated histology 1
• No lymphovascular invasion 1
• No tumor budding 1

If any criterion is not met, surgical resection with lymph node dissection is required because the risk of lymph node metastasis increases to 10-18% with deep submucosal invasion. 1

Summary of Action Steps

For your rectal polyp with high malignancy risk features:

• Non-pedunculated: Biopsy, tattoo, refer to surgery—do not attempt resection 1
• Pedunculated: Perform hot snare polypectomy, assess histology, then determine need for surgery based on pathologic risk factors 1, 3
• If considering ESD: Refer to advanced endoscopist experienced in ESD technique, ensuring the lesion lacks overt deep invasion features 1