S Subramonia Lap Colorectal Surgeon

Colorectal NSSG Audit Event Day

Durham 12 Sep 2014

• Role of colonoscopy in the treatment of malignant polyps

• Pathology of malignant colorectal polyps

• Assessing the risk of residual disease post-polypectomy

• Surgical salvage of the high-risk polyp

• Staging & non-endoscopic surveillance of malignant

polyp

Endoscopist BEFORE Histopathologist

• Predict polyp histology by morphology – OPTICAL Bx

• Aim for en bloc resection – AVOID piece-meal

Endoscopist BEFORE Histopathologist• Endoscopy reporting

Site – Right Vs left colon (splenic flexure)

Size – >35mm – 75% of carcinoma

Pedunculated / Sessile - Villous 15% risk of Ca

Morphology – irregular, ulcer, hard, broad stalk

Paris classification of appearance

Kudo classification of pit pattern

Laterally spreading lesion

Non-lifting sign

One-piece / Piecemeal Completeness of excision

Benign / Malignant

HistopathologistMalignant Colorectal Polyp

is a lesion in which neoplastic cells have invaded through

the muscularis mucosae into the submucosa.

pT1 adenocarcinoma

is defined as invasion into the submucosa but not into

the muscularis propria

Carcinoma in situ / intramucosal carcinoma - OBSOLETE

(High Grade Dysplasia)

Histopathologist• Degree of differentiation

• Size – microscopic assessment is most accurate

• Level of invasion into polyp – Haggitt & Kikuchi

Histopathologist

• Depth of invasion into submucosa

Haggitt Kikuchi

Histopathologist

• Degree of differentiation

• Size – microscopic assessment is most accurate

• Level of invasion into polyp – Haggitt & Kikuchi

• Resection margin ≤ 1mm is an involved margin

• LVI, tumour budding, cribriform histology

Histopathologist

• 2nd opinion due to interobserver variability

Degree of differentiation

LVI

Estimation of risk of residual disease

• Malignant polyp – Colorectal MDT

• Estimate the risk of residual disease

Technique of resection

Resection margin

Degree of differentiation

Depth of invasion – Haggitt and Kikuchi

LVI

Estimation of risk of residual disease

Surgery should be considered, provided that the patient

is fit enough to undergo such surgery where

• resection margin is deemed to be involved (< 1 mm)

• Haggitt Level 4 or Kikuchi sm3

• Kikuchi sm1 or sm2 with adverse histology

• Poorly differentiated – is unusual

Colon Vs Rectum differences

Estimation of risk of residual disease

Surgery should be considered, provided that the patient

is fit enough to undergo such surgery where

• resection margin is deemed to be involved (< 1 mm)

• Haggitt Level 4 or Kikuchi sm3

• Kikuchi sm1 or sm2 with adverse histology

• Poorly differentiated – is unusual

Lymphovascular invasion Tumour budding

Cribriform Mucinous

In isolation NOT

High risk

Estimation of risk of residual disease

Surgical decision making in high-risk polyps

Fitness

Life expectancy

Impact of morbidity

Mortality

Patient wishes

Surgery if predicted op mortality (CR-POSSUM) < risk of residual disease

It should be remembered that even in ‘high-risk polyps’, it is more likely that the resected specimen will NOT contain any evidence of residual disease at the polypectomy site or in draining lymph nodes.

Staging and surveillance - TNM

• T – Little data on use of MRI or EUS for residual disease

• N – MRI or EUS unreliable

(Not accurate enough to judge whether a visible

lymph node does NOT contain cancer)

• M – CTCAP

Staging and surveillance - TNM

Endorectal US should be performed on all rectal

polyp tumours prior to transanal or surgical excision

(good practice BUT no good evidence)