Colorectal Flashcards
How would you treat an acute anal fissure?
Assess for red flag features
Stool softeners
GTN 0.2% for 8 weeks (or 2% Diltiazem) –> 60-70% response
If fails EUA +/- biopsy +/- Botox 25 units either side into internal anal sphincter (90% success)
If fails anal manometry and endoanal US
What proportion of colorectal cancers are associated with HNPCC?
-This is Lynch syndrome - about 3-5%
What is the Genetic defect in Lynch Syndrome?
Usually MMR deficiency
What screening should patients with Lynch syndrome receive?
2 yearly colonoscopy from 25-75 for MLH1/MLH2
and from 35 for MSH6/PMS2 mutations
2 yearly OGD from 50
Annual TVUSS and ca125
Annual renal USS
What are the extra intestinal manifestations of Lynch syndrome?
30-70% endometrial cancer
5-10% Gastric cancer
(30-70% Colorectal cancer)
What screening should patients with FAP receive?
Colonoscopy 1-3 yearly from 12-14 until resection.
OGD from 25
What is the mutation seen in FAP?
5q21 APC gene (80%) Autoosomal dominant
What surveillance should be performed in patients ‘at risk’ of APC without an identified APC mutation?
Colonoscopy 5 yearly from 12-14
Where are polyps seen in FAP?
Colonic - 100% - Cancer risk of near 100%
Gastric fundal - 50%
Duodenal 90% - if severe risk of 30% Ca at 10 years)
What eye condition is associated with FAP?
Congenital hypertrophy retinal pigmentation epithelium (CHRPE)
What is Gardner’s syndrome?
FAP + Oestoomas, thyroid cancer, epidermoid cysts and fibromas
Jaw osteomas, extra teeth
What are some indications for surgery in FAP?
Polyps >10mm, HGD, substantial increase in polyp burden
What medical treatments can be used for FAP with intra-abdominal desmoids?
Sulindac + SERM
What surveillance should be conducted for Peutz Jeghers syndrome?
OGD, Colonoscopy and video capsule at 8 years.
Capsule 3 yearly, if polyps also OGD/Colon 3 yearly, otherwise at 18
What is the mutation in Peutz Jeghers syndrome?
STK11 mutation on Chromosome 19 (Dominant)
What types of tumours are most commonly seen in Peutz Jeghers?
Harmartomas
20% risk of CRC and 5% Gastric Cancer
Also breast, ovarian, cervical, pancreatic and testicular
What is the mutation in Cowden disease?
PTEN 10q22
89% Ca any site
81% Breast
16% CRC
Also thyroid and uterine
Some overlap with Juvenile polyposis syndrome
What effect does 5-ASA have on fertility?
80% of males develop sperm dysmotility
What is 6-metacaptopurine (6-MP)
A thiopurine (purine analogue) depressing inflammatory cascade by affecting folic acid and DNA synthesis.
Can take up to 6 weeks for clinical response, 30% of patients are intolerant.
What proportion of patients develop parastomal hernias?
Colostomy - 60%
Ileostomy - 30%
How is a rectal prolapse graded?
Grade 1 - No lower than proximal limit of rectocele
Grade 2 - into rectocele but not top of anal canal
Grade 3 - descends to top of anal canal
Grade 4 - descends into anal canal
Grade 5 - protrudes from anus
What proportion of patients with SRUS respond to biofeedback?
75%
If fails – consider stapled transanal rectal resection (STARR) or VMR
What is the success rate of GTN/Diltiazem for fissure?
20-70%
What medication can reduce the risk of CRC in Lynch syndrome?
Aspirin if taken for >2 years (NICE)
Which patients with rectal cancer should be offered radiotherapy/chemoradiotherapy
cT3-cT4 or cN1+
What is the recommended volume of procedures for rectal cancer?
Annual site of >10 and individual >5
Which patients with colon cancer should be considered for preoperative treatment?
cT4 only
FOXTROT trial 2019 - FOLFOX (5-FU, Folinic Acid and OXaliplatin)
What adjuvant treatments are suitable for colorectal cancer patients?
If short course RT or no preoperative treatment
Stage 3 disease (N+ve)
CAPOX 3 months or FOLFOX 6 months
What is the most common side effect of treatment with oxaliplatin?
Sensory neuropathy
What are common side effects of 5-FU?
Diarrhoea
Epistaxis
Plantar-palmar erythema
What is the most common site of large bowel carcinoid?
Caecum
Who receives bowel screening in the UK?
Every 2 years from 60-74 (working towards 50) –> FIT test, if abnormal –> colonoscopy
What is the risk of cancer in a 5mm polyp?
near 0%
6-15mm -3.3
26-25mm 18.7
26-35mm 42.7
>35 75.8
How are colonic polyps described?
Using the Haggitt and Kikuchi classifications.
The Haggitt classification is for pedunculated polyps - Level 1-4
Kikuchi for sessile
Haggitt 4 (into submucosa) and Kikuchi SM2/3need excision (LN 8-27%)
What colonoscopic surveillance should be offered to patients treated for colorectal cancer?
Colonoscopy at 1 year
For patients with polyps found and excised at colonoscopy, how should they be surveilled?
If ≥5 premalignant, or ≥2premalignant including 1 ≥10mm or dysplastic, or large polyp >2cm completely excised en bloc –> 3 yearly colonoscopy
If large polyp incompletely excised or piecemeal –> 2-6 month check and again at 1 year.
If none of these, discharge. Also if life expectancy less than 10 years or >75
Where is botulinum toxin A injected for fissure?
Internal anal sphincter 15-30 units
What is Park’s classification of fistula?
Course relating to EAS/IAS and Levators
Inter, Trans, Supra, Extra
What is Goodsall’s rule?
If external opening posterior to transverse anal line, will have curvilinear tract to posterior aspect of anal canal in midline
If external opening anterior to transverse anal line, will have a radial tract, unless >3cm from anus
What proportion of patients with ileocaecal Crohns disease will require surgery?
> 90% - mainly strictures
10-15% of colitis cannot differentiate CD from UC
What is the risk of colon cancer with UC with pancolitis?
5% at 10 years
20% at 20 years
Overall rates are 2% and 8% (similar for Crohns)
What proportion of patients with UC present with proctitis?
30%
What proportion of patients with UC have pancolitis?
20%
What histological findings are present with solitary rectal ulcer syndrome?
Extension of the muscularis mucosa between crypts and muscularis proprietor disorganisation
What is MUIR-TORRE syndrome?
HNPCC + associated skin lesions (epidermoid cysts + keratoacanthoma)
What is the active ingredient of Klean Prep?
Polyethylene glycol made into solution up to 4L
Difficult to consume, but minimal electrolyte disturbances
Sodium picosulphate is administered how?
2 x 45ml solutions - better tolerated, but risk of electrolyte disturbances
What is the recurrence rate after a Delormes’?
50% at 5 years
Unsuitable for internal prolapse
In which patients should a STARR procedure be considered?
High grade internal rectal prolapse with obstructive defecation symptoms
How are rectal tumours defined?
Within 15cm of anal verge.
Intramural spread is usually <1cm distally
When is EUS useful for rectal tumours?
If T1 where TEM is considered
What findings predict a clear CRM for rectal cancer?
Distance >1mm on MRI
When should surgery be performed after short course RT for rectal cancer?
4-8 weeks - similar oncological outcomes and decreased complications to 1 week
cf 6-10 weeks Long course CTX
How much radiotherapy is given for short course in rectal cancer?
25Gy (5 x 5)
vs 50.4 for long course (1.8 x 28)
Which trials support short course RT for rectal cancer?
Swedish Rectal Cancer Trial (cT1-3) - but before TME
Followed by CKVO 95-04 with TME, where reduced local recurrence but OS same
What evidence for long course CTX in rectal cancer?
German Rectal Cancer trial
When is long course CRT usually given for rectal cancers?
T4 with threatened CRM
When is long course CTX usually given in rectal cancer?
T4 with threatened CRM
When is a low anterior resection performed?
Rectal tumours where a 2-5cm distal clearance margin can be gained
Minimum of 1cm
How many lymph nodes should be examined in a CRC specimen?
At least 12
What is the local recurrence rate after a traditional AP?
about 15%
What chemotherapy is used in liver metastasis of CRC?
FOLFOX 4, started prior to liver resection for about 3 months
What is the rate of recurrence after liver resection for colorectal liver metastasis?
up to 60%, usually within 1-2 years
What features make a colorectal liver met resectable?
Four or fewer segments/deposits
Residual liver volume >40%
IVC not involved
What features make a colorectal liver met irresectable?
Invovement of two portal branches
Involvement of three hepatic veins
Marked extra hepatic disease
What is the commonest extraintestinal manifestation of UC?
Arthropathy (also in CD)
PSC and Uveitis more common in UC
Which eye manifestation of IBD is more common in Crohns?
Episcleritis
What are the pathological findings of UC?
Confined to mucosa/submucosa
Widespred superficial ulceration with preservation of adjacent mucosa (pseudopolyps)
Inflammatory cell infiltrate in lamina propria
Crypt abscesses
Depletion of goblet cells
What is the peak incidence of UC?
15-25 and 55-65.
UC is less common in smokers
What is the optimum length of ileostomy?
about 2.5cm
What is the output of a normal ileostomy?
5-10ml/kg/24 hours
If in excess of 20ml/kg/24hours will need supplementation
What is the most specific imaging investigation for colonic polyps?
CT colonoscopy
What injection sclerotherapy agent can be used for haemorrhoids?
5% phenol in almond oil (not 88%!)
What proportion of FAP cases are sporadic?
20-25%
Causes 0.5% of CRC
What proportion of adenomas >1cm have a KRAS mutation?
50%
When is cetuximab useful?
Wild type KRAS +/- irinotecan
What length of ileostomy can be denuded from its mesentery?
5cm
How should patients with cRC be imaged postoperatively?
Twice within 3 years usually at 6 and 18 months, with 6 monthly CEA for 3 years.
If having chemotherapy, perform first scan at end of treatment
If had liver resection usually 6monthly intervals for 2 years
Where do anal fissures most frequently occur?
Posterior midline (90%) - more likely to be anterior in females
Multiple fissures raises suspicion of Crohns disease, TB or internal rectal prolapse
What are the functional consequences of sphincterotomy?
Incontinence to flatus in 30%
For low pressure anal fissure, what is the definitive treatment of choice?
Advancement flap
How is a simple uncomplicated anal fistula defined?
Low, involving <30% of external sphincter
What is the success rate for fibrin glue for fistula?
50% healing at 6 months - of whom 25% will have a recurrence
Plugs (don’t work) and cutting setons (incontinence) not recommended
What is the success rate of a LIFT procedure?
Ligation of intersphincteric tract - up to 90%
What is the incidence of anastomotic leak in low anterior resection?
8-20%
There is no evidence that placement of drains affects this. For exam, should place defunctioning ileostomy
What is the 5 year survival of patients treated with salvage APER after failing to respond to CRT?
40%
What is the most common side effect of stapled haemorrhoidectomy?
Urgency
What is the most common type of Fistula-in-ano?
Intersphincteric (70%)
Trans (25%), Supra (4%), Extra (1%)
In infants how should low anal fistulas be managed?
Just lay them open. Rarely associated pathology
What is the predominant blood supply to the splenic flexure?
Left colic branch of IMA in 89% of cases –> default left hemicolectomy
In emergency setting for obstruction, probably extended Right is the correct choice
What is the risk of progression of AIN III to cancer?
10% at 10 years, 30% if HIV+ve
Therefore 6 monthly follow up
What is the innervation of the anal sphincter?
Pudendal nerve S2-4
Autonomic fibres from within colon and external innervate internal sphincter
How can faecal incontinence be graded?
Wexner faecal incontinence score (Cleveland clinic)
0 (absent) -4 (daily)
Incontience to gas, liquid, solid, wearing pad and lifestyle changes
9+ = severe
What investigations are warranted for faecal incotinence?
EUS
Anorectal physiology studies
Defecating proctogram
What are the treatment options for faecal incontinence?
Conservative (loperamide, laxative, biofeedback)
SNS modulation - usually S3 temporary electrode and permanent for responders. PNE or barbed wires
What is the Paris classification of polyps?
Global polyp description.
1 -protruded (pedunculated/sessile)
0IIa - Flat elevated
0IIb - Flat
0IIc - Flat depressed (highest risk)
What microscopic changes are seen with CMV colon (2)?
Large intranuclear inclusions body
Smaller cytoplasmic inclusions
What microscopic changes are seen with UC (3)?
Alteration of crypt architecture
Dense neutrophilic infiltrates and crypt abscesses
Ulceration with pseudo polyps
What microscopic changes are seen with Crohns disease (4)?
Granulomas (non caveating epiheliod cell aggregates with Langhans’ giant cells
Submucosal fibrosis
Fissuring
Areas of chronic inflammation
What microscopic changes are seen with radiation enteritis (4)?
Disordered crypts
Endarteritis obliterans
Fibrosis of lamina propria
Ulceration and fistulation
What microscopic changes are seen with infective colitis (3)?
Increased cellularity in the lamina propria
Neutrophilic infiltrates
Loss of crypts
What microscopic changes are seen with SRUS (3)?
Fibromuscular obliteration
Surface ulceration
Little inflammatory activity
How frequently does pouchitis occur?
50% after restorative proctocolectomy, with chronic pouchitis accounting for 10% of pouch failures.
Should be diagnosed luminally followed by treatment with 2/52 of metro/cipro
Sometimes get prophylaxis
What are the common extra intestinal manifestations of Crohns disease (10)?
Related to disease extent Unrelated to disease extent
Aphthous ulcers (10%) Sacroiliiitis (10-15%)
Erythema nodosum (5-10%) Ankylosing spondylitis (1-2%)
Pyoderma gangrenosum (0.5%) Primary sclerosing cholangitis (Rare)
Acute arthropathy (6-12%) Gallstones (up to 30%)
Ocular complications (up to 10%) Renal calculi (up to 10%)
With anal cancers, what proportion of enlarged inguinal nodes are metastatic?
About 50%. The remainder being enlarged due to infection
What investigations are required for Anal cancer?
EUA, rigid sigmoidoscopy + biopsy
If confirmed, MRI, CTCAP, PET-CT
What is the primary treatment strategy for anal cancer?
Chemoradiotherapy - IV 5-FU and Mitomycin C with 50gy of radiation –> 80% cure rate
Combined > Radiotherapy
Complications - Diarrhoea, mucositis, myelosuppresion, skin erythema, desquamation, anal stenosis and fistula formation
What is the FIT test?
Antibiodies that specifically recognise human Hb
Reduced false positives compared to FOB
FIT <10 0.6% CRC
FIT>10 9.4% CRC
FIT >400 22.4% CRC
Sensitivity 70-80%
What is the prevalence of diverticular disease at 40, 50 and 80?
10% <40
50% >50
70% 80
Which rectal tumours can be considered for local excision? (TEMS, TAMIS, TEO)
Well/moderately differentiated
No EMVI
<4cm and <30% circumference
T1
What is the rate of lymph node metastasis according to SM stage for T1b rectal cancer?
SM1 - <3%
SM2 8-11%
SM3 12-25%
What are the modalities of obstetric faecal incontinence?
1) Sphincter injury (tear, forceps)
2) Pudendal neuropathy (reduced anal sensation and squeeze pressures)
What are contraindications to placement of a SNS?
Full thickness rectal prolapse
Active IBD
Pregnancy
Skin disease
Anatomical limitations
Psychiatric disease
Congenital malformations
When might you consider an anal sphincter repair?
Young patient failed conservative treatment
Non smokers, normal BMI
At least 3 clock face arm defect
What are the Spigelman criteria?
For assessing duodenal polyps in FAP and deciding on screening/intervention
What is the most common cause of death in patients with FAP?
Intra-abdominal desmoid
In patients at high risk of FAP how should they be surveilled?
Annual Flexi from 13 and colonoscopy every 5 years from 20.
No OGD unless diagnosed FAP
When should surgery for FAP be performed
Usually 16-18 - then 6-12 monthly Flexi sig if IRA and annual pouchoscopy if RPC.
Don’t forget OGD at 25
What is the cumulative rectal cancer risk with a colectomy/IRA in patients with FAP?
30% by 60
What is the difference between traditional APE and Extra-levator APE? (ELAPE)
APE has higher CRM+ and perforation than anterior resection
ELAPE avoids the coning down that occurs towards the anal canal
In which patients with UC should a pouch not be considered?
Poor anal sphincter
Possibility of Crohns
Active anal lesions
Sclerosing cholangitis (high rate of pouchitis)
Fecundity
What are the potential complications of pouch surgery?
Anastomotic Leak 5%
Pouch failure 10%
Stricture and SBO 10%
Pelvic sepsis 15%
Pouchitis 30% (occurs in 10% in FAP)
Reduced fertility in women and sexual dysfunction (25%)
Stool frequency x 8 and 2 at night
Incontinence 5-10%
Mortality 0.4%, morbidity 30%, reoperation 16%
How are obstetric injuries classified?
Sultan system
1st - perineal skin/vaginal mucosa
2nd - perineal muscles only
3a - <50% EAS
3b - >50% EAS
3c Both EAS and IAS
4 rectal mucosa
What are the side effects of taking long term metronidazole?
Peripheral neuropathy if > 6weeks
How is a high anterior resection defined?
Tumour above peritoneal reflection.
Alternatively could say >10cm from anal verge (low 6-10 and ultra low <6)
What surgical approach is optimal for Rectal prolapse?
The PROSPER trial 2013 showed no difference between approaches (recurrence 13-24%), but was abdominal/perineal approach was surgeons choice
Which study provides evidence for the use of TXA in a trauma setting?
The CRASH 2 trial
Early administration (<1 hours > than 1-3 hours) reduces risk of death in bleeding patients
How should an extraperitoneal rectal injury be managed?
If <25% circumference and accessible transanally can be repaired primarily. If no accessible, then can observe. If >25% circumference will need drainage and diversion
How is a colonic transit study conducted?
Ten makers ingested on six consecutive days with an AXR on the 7th day.
2.4 x number of markers == colonic transit time
Delayed if 48 hours or 20 markers visible
What are the Truelove and Witts criteria?
Combination of number of blood motions, pulse, temperature, Hb and ESR/CRP.
Severe features suggest need for colectomy, especially at 48 hours
Blood stool >6, tachycardia, fever, anaemia, CRP>90/ESR>30
For patients with severe colitis and >8 stools per day at 48 hours, how frequently is a colectomy required?
85% chance - also if raised CRP >45 and 3-8 stools per day
If stable can still have Infliximab or Cyclosporin
What are some options for surgical treatment of pilonidal disease?
Bascom 1 – Lateral Incision and excision of pits with diamond shaped
Bascom 2/cleft lift – Excision of large area off midline but including midline. Lateral side mobilised, about 4cm excised, superficial flap
Karydakis – similar but a deep flap sutured to deep fascia
Gips – trephine pit excision
Limberg, Z-plasty, V-Y flaps, Rhomboid