Dr Linus Chang Gastroenterologist Mrs BP 67yo woman referred for screening colonoscopy for ve FOB Index colonoscopy in Sep 2009 Multiple polyps largest was resected TVA Rebooked 8mo later for resection of remaining smaller polyps ID: 524572
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Slide1
When Is A Colonoscopy Not a Colonoscopy
Dr Linus Chang
GastroenterologistSlide2
Mrs BP
67yo woman – referred for screening colonoscopy for +
ve
FOBIndex colonoscopy in Sep 2009Multiple polyps; largest was resected (TVA)Rebooked 8mo later for resection of remaining smaller polypsSlide3
Mrs BP – Colonoscopy 6mo later
Caecal ulcer
Failed to lift with submucosal injection of saline
Biopsied -> Carcinoma in situSlide4
Caecal view Sep 2009
Caecal view May 2010Slide5
Mrs BP - Surgery
Proceeded to R hemicolectomy
Early T2 CRC -> just infiltrating muscularis propria
Loss of nuclear staining seen for MLH1 and PMS2 (consistent with microsatellite instability)0/10 lymph nodes involvedNo adjuvant chemo recommendedTumour was surrounded by flat lesions which were sessile serrated adenomas (SSA)Slide6
Colorectal Cancer
2
nd
most common cause of cancer deathCauses 9% of cancer death overallSlide7
Colonoscopy in screening for CRC
Screening colonoscopy in 1994 asymptomatic adults
5.7% had advanced neoplasms
Lieberman DA, et al N Engl J Med. 2000;343(3):162Asymptomatic individuals (mean age 61) colonoscoped then followed for 8 years have reduced CRC incidence and death compared to expected incidence and SEERS data Kahi CJ, et al. Clin Gas Hepat. 2009;7(7):770Slide8
Expected Adenoma Detection Rate
Overall, in 10034 colonoscopies,
29.1%
had at least 1 adenoma removed.Males vs Females (24.5% vs 16.7%; p<0.0001)Chen & Rex J Clin Gastro 2008; 42(6): 704-707Age305070> 1 adenoma or cancer14.6% (13.2-16)
23.3%(20.1-26.9)35.2%(29.5-41.4)
> 1 nonadenoma/noncancer
26%(24-28.1)
27.6%(24.3-31.3)
29.3%(24.5-34.6)
⏎Slide9
Risks of Colonoscopy
1 in 1000 of perforation or major bleeding
0.8/1000 if no biopsy
7/1000 if polypectomy or biopsySlide10
Polyp detection depends on
endoscopist
Risk of interval cancer between screening colonoscopy and repeat procedure depends on endoscopist’s adenoma detection rate
Withdrawal time of 6 minutes or more increases adenoma detection rate Barclay RL, et al. N Engl J Med. 2006;355(24):2533Slide11
Less effective in R sided lesions?
Colonoscopy reduces deaths mainly from L sided CRC, but not R sided lesions:
Baxter NN, Ann Intern Med. 2009;150(1):1.
Singh H, Gastroenterology. 2010;139(4):11285% of CRCs arise as “interval” cancers following a colonoscopySlide12
Sessile Serrated Adenomas
Distal polyps usually follow conventional adenoma-carcinoma sequence
Up to 20% of all
CRCs may arise from serrated polypsOnly recognised as recently as 2003Serrated pathway polyps become cancers with high levels of microsatellite instability (MSI)Can become cancers more rapidly than conventional adenomasSlide13
This is what we’re missing!
⏎Slide14
Sessile Serrated Adenomas (2)
SSAs
represent
1-9% of all polypsPresent in 1-4% of the general populationMedian age of patients 61Trend toward female gender biasMore commonly in the proximal colonEndoscopic appearance:5mm or largerFlat or depressedCovered by adherent layer of yellowish mucus
In patients with at least one SSA12% have LGD; 2% have HGD; 1% have
adenocarcinomaHuang CS, et al. Am J Gastro 2011; 106: 229-240
⏎Slide15
Natural History of SSAs
Lu F, et al. Am J of
Surg
Path 2010; 34(7):927-934All colonic polyps dx between 1980-2001 studied1402 hyperplastic polyps81 polyps in 55 pts rediagnosed as SSA40 SSA pts with no prev hx of CRC or AP-HGDOf these, 5 developed CRC, 1 developed AP-HGDCRC more
commong in SSA pts than in controls with HP (12.5% vs 1.8%) and AP (12.5% vs
1.8%)All subsequent CRC or AP-HGD developed in proximal colon4 of 5 subsequent CRC showed MSI
Conclusion: 15% of SSA pts developed subsequent CRC or AP-HGD; especially in the R colonSlide16
Risk factors for developing SSAs
Cigarette smoking
Obesity
Female genderFamily history of CRC or polypsSlide17
How quickly to
SSAs
progress to cancer
We don’t knowCase study suggesting SSA-> CA in 8 monthsMrs BPSlide18
Surveillance post-resection
SSA with no dysplasia
5 years if <3 lesions, all <1cm in size
3 years if 3 or more, or any 1cm or more in sizeSSA with dysplasia3 yearsScreening of first-degree relatives at age 40, or 10y prior to age of diagnosisSlide19
We are missing SSAs!
Mortality rates from R sided CRC not decreasing despite increasing use of screening colonoscopy
Interval cancers more likely to occur in proximal colon and demonstrate microsatellite instability suggesting they arise from SSAs
Adherent mucus coating is not a useful endoscopic sign unless prep is very goodSlide20
Recognising SSAs
Colonoscopy is the only reliable technique
Increasing recognition of SSA
6 min withdrawal timeSplit dose bowel preparationAdvanced imaging techniquesNarrow Band ImagingIndigo Carmine spraySlide21
Split dose Colonic Preparation
Traditional colonic preparation consists of solution given day prior to colonoscopy
Split dose prep involves giving for example, 2L of prep the day prior, and 1L on the morning of colonoscopySlide22
Clear superiority of Split Dose Prep
Achieves better cleansing than conventional
Good/excellent views 75%
vs 43% (p=.00001)Best views within 8 hours of last fluid intakeAdenoma detection rates higher24% vs 12%, (p=0.001)Lower rates of failed caecal intubation1% vs 11%; (
p=0.00001) Fewer aborted procedures
7% vs 21%, (p<0.0001)
Marmo
R, et al.
Gastrintest
Endosc
. 2010 Aug; 72(2):313-20.Slide23
Patient acceptance of split-dose bowel prep
In comparisons bet split dose and conventional:
Higher patient satisfaction scores
Higher “no or minimal difficulty” completingNo significant difference in percentage of patients who stop for a bowel movement on way to procNo difference in compliance Khan, MA, et al. J Clin Gast. 2010; 44(4):310-1 (Letter) Park, JS, etal. Endoscopy. 2007; 39(7):616-9
Majority of patients willing to get up early to take split dose Rex DK, et al. Dig Dis Sci. 2010; 55(7): 2030-4Slide24
Anaesthetic
concerns re morning prep
Traditionally patients have fasted overnight for colonoscopy
Some anaesthetists argue that aspiration risk higher if morning prep is takenBut residual gastric fluid volume similar between split-dose regimen vs conventional Huffman M, Gastrointest Endosc. 2010 Sep; 72(3): 516-22Anaesthetic guidelines have reduced precolonoscopy fasting to 2 hours.Slide25
Image Enhanced Colonoscopy
Includes:
Endoscope based image enhancing:
NBI (Olympus)iScan(Pentax)ChromoendoscopyIndigo carmine dyeSlide26Slide27Slide28Slide29
NBI/FICE/iScan
iScan
(
Pentax) increases detection of neoplasia over white light (38% vs 13%) FICE (Fuji) showed no difference in adenoma detection over white light NBI (Olympus) increases detection of flat adenomas over white light, but not adenomas overall. FICE (Pentax) vs Indigocarmine – no difference in adenoma detection rates
Hoffman A. et al. Endoscopy. 2010 42(10):827-33Chung SJ, et al. Gastrointestinal Endoscopy. 2010; 72(1):136-42
Paggi S, et al. Clin Gas & Hep. 2009; 7(10) 1049-54
Pohl J, et al. Gut. 2009; 58(1):73-8
Slide30
Chromoendoscopy
Spraying of indigo carmine through the flushing channel of the colonoscope
Increases detection of flat lesions and hyperplastic polyps, but not of adenomas overall.
Le Rhun M, et al. Clin Gas & Hep. 2006; 4(3):349-54Slide31
What makes a colonoscopy a (good) colonoscopy?
SPLIT DOSE COLONIC PREP
At least 6 minutes withdrawal
+/- image enhancing in the R colon (NBI or indigo carmine)Endoscopist consciously looking for flat R sided lesionsSlide32
Endoscopist Report Card
Ultimately all endoscopists should audit their adenoma detection rate
My performance in 81 colonoscopies between Mar and May 2013 at 1 facility:
Successful caecal intubation100%Split Prep100%Prep “good or satisfactory”93%
Complications0%
Adenoma Detection Rate(incl
SSA)
45.6%
SSA percentage of all polyps
18.9%
SSA detection rate
8.7%