Emerging Interventions in Endoscopy Margaret Vance Nurse Consultant in Gastroenterology St Mark s Hospital
Colon Cancer Colon cancer is common. 1 in 20 people in the UK will develop the disease 19 000 deaths per year. Majority of cases are sporadic cancers, Familial cancers accounting for less than 5% of all colorectal neoplasms. Sporadic colorectal cancers are thought to develop in pre-existing adenomas. The prevention of colon cancer therefore depends on the detection, safe removal and post-procedure surveillance of colonic adenomas.
Prevention, Detection and Treatment Three stages Screening bowel scope, FOBt, FIT. Detection improved polyp detection modalities. Minimally Invasive endoscopic treatments TASER, ESD.
Screening Bowel scope 2013 55 years old single flexible sigmoidoscopy Stool testing 2005 FOBt screening FIT
Occult Blood: What do we Detect? Guaiac detects the presence of the haematin moiety. Immunochemical methods detect the protein chains.
How is FIT different to gfobt? FIT Faecal Immunochemical Test gfobt Guaiac Facal Occult Blood Test Higher detection rate of cancers & adenomas Estimated 22% reduction in CRC mortality TRIAL positivity rate about 6.5% More expensive than gfobt Lower detection rate of cancers and adenomas Estimated 16% reduction in CRC mortality Current BCSP positivity rate 2.04% Less expensive than FIT
How is FIT different to gfobt? FIT Faecal Immunochemical Test Measures HUMAN blood Single faecal sample Sample put into plastic container Automated objective analysis Adjustable Hb cut-off concentration Higher participation rate than gfobt gfobt Guaiac Facal Occult Blood Test Measures any blood including that in the diet 6 faecal samples from 3 bowel motions Sample put onto cardboard Subjective visual assessment Non-adjustable Hb cut-off (sensitivity) Lower participation rate than FIT
Colonic Polyps Colonic polyps tend to be protuberant lesions in the mucosa. Although two-thirds of colorectal cancers are thought to develop from sessile and pedunculated adenomas, many of the remaining cancers may well be attributed to morphologically distinct flat or depressed lesions.
Flat lesions Flat lesions can be slightly reddish in colour and may be associated with a central area of depression. They are difficult to spot, optical techniques such as chromoendoscopy and narrow band imaging, if available, can also be helpful.
Detection methods - Chromoendoscopy Chromoendoscopy describes the application of dye, usually 0.1% indigocarmine and often via a spray catheter, to the colonic mucosa. It improves the identification of flat and depressed lesions.
A B A Dye spray catheter C B 3mm polyp without dye-spray C 3mm polyp with dye-spray
Narrow Band Imaging (NBI) NBI is a high-resolution endoscopic technique that enhances the fine structure of the mucosal surface without the use of dyes. It is based on the relationship between the light s wavelength and its depth of penetration. Optical filters are used in the light source during colonoscopy to increase the relative concentration of blue light, resulting in clearer surface detail such as microvasculature. White light Narrow Band Illumination #2:bandwidth #1:centre wavelength NBI Filter = Specially Coated Glass
Narrow Band Imaging (NBI) 2mm adenoma with white light 2mm adenoma with NBI
High resolution & magnification High magnification colonoscopes magnify the endoscopic image up to 100 times High resolution scopes have increased pixel density and improve detail discrimination. Allow different mucosal pit patterns to be identified.
Pit pattern with magnifying endoscopy Type I Tupe II round pits stellate pits NORMAL / POST- INFLAMMATORY METAPLASTIC Type III L large tubular or roundish pits ADENOMA Type III S Type IV small tubular or roundish pits gyral or sulcal pits ADENOMA ADENOMA/VILLOUS ADENOMA Type V Non-structured CANCER
High resolution & magnification 2mm adenoma with type III L pit pattern 2mm adenoma with type IV pit pattern
Endoscopic Paris classification
Histological classification of polyps Category Polyp type Qualification of dysplasia Conventional Adenomas Tubular adenoma Tubulovillous adenoma Villous Adenoma +high-grade dysplasia /invasive adenocarcinoma Serrated Adenomas Hyperplastic polyp Sessile Serrated Adenoma/polyp Traditional serrated adenoma Serrated polyp, unclassified + dysplasia (low/high-grade) + high-grade dysplasia
Polyp Removal The majority of polyps can be removed endoscopically depending on their size, characteristics and accessibility. Larger stalked polyps are usually snare resected, whilst sessile polyps require lifting with submucosal injection to avoid thermal damage. Large stalked polyp Stalk post snare resection
Endoscopically non-removable polyps Polyps that are probably not removable endoscopically are: large sessile polyps extending beyond 50% of the bowel wall circumference large rectal polyps abutting the dentate line lesions encircling the appendix those with generally poor endoscopic access those with submucosal invasion
The Non-Lifting Sign Submucosal invasion can be diagnosed when a polyp fails to lift with a submucosal injection of saline. This so-called non-lifting sign suggests malignancy and these lesions should be biopsied, tattooed and referred for surgical resection.
Endoscopically non-removable polyps & the Non-Lifting Sign Normal lift with submucosal injection Failure to lift with submucosal injection
Management of rectal polyps endoscopy/surgery The options type of polyp available expertise patient wishes Snare polypectomy EMR (piecemeal) ESD Trans-anal excision or TEMS Low anterior resection Abdo-perineal resection
Anatomy of Rectum canal peritoneal reflexion 12-15cm from anal capacious, distensible rectum
Low rectal polyp
After ESD Tubulovillous adenoma with focal HGD
TASER technique: ideal platform for complex rectal polyp resection (P-EMR, ESD, etamis) Gel air-tight seal Endoscope - CO2 insufflation - visualisation - cutting/coagulation/clipping 1-2 laparoscopic retractors or laparoscopic cut/coag. or suturing/clipping Side port for removing smoke GelPoint Path SILS port Saunders BP et al. Gastroenterology 2013: 145: 939-41 Tsiamoulos ZP, Warusavitarne J, Saunders BP. Endoscopy. 2014;46 Suppl 1 UCTN:E401-2.
In Summary Multi modal approach to prevention, detection and treatment of colorectal cancer. Endoscopy at the forefront, emerging new technologies. Develop patient information, providing all options available.