Bowel cancer Flashcards
Colorectal cancer epidemiology
- Prevalence
- Mortality
- Prognosis
- Age
- Sex
Prevalence+ mortality: 4th most common in UK
- 2nd most common death.
Prognosis: 60% survival with surgery.
Age: 70+ (60%)
Sex
- M> F, 3:1
Colorectal cancer risk factors (9)
- Male (3:1)
- Increasing age
- Smoking
- Family history
- Polyps
- Alcohol
- Obesity
- IBD
- Polyposis syndromes: FAP, HNPCC
Two-week referral criteria
40 + with unexplained weight loss
50+ with rectal bleeding
60+ with iron deficiency anaemia
60+ with change in bowel habit
Rectal/ abdominal palpable mass.
Colorectal cancer diagnosis
Luminal:
- Gold standard- colonoscopy
- Flexible sigmoidoscopy: sigmoid most common area of pathology
- Obstructive symptoms/ Fe def anaemia= OGD
Radiological Imaging:
- CT/MRI/ USS/ PET CT
- CT Colonography (risk of perforation): false positives, not interventional
- CT CAP for staging
- Rectal staging= MRI
Colonoscopy and flexi sigmoid complications
Bleeding Perforation Missed pathology AKI Risk of sedation.
Flexi Gives limited study. - Can miss pathology
Duke staging of colorectal cancer
- Method of staging
- Stages
Gold standard= thoracoabdominoplevic CT
Local cancer
- Colon= CT
- Rectal, pelvic= MRI
With 5 year survival:
A- Penetration into submucosa.
B- 1. Penetration into propia (>90)
2. Penetration through bowel wall (80-85%)
C- 1. Into propia, LN metastasis. (50-65%)
2. Through bowel wall, LN Mets (>90%)
D- Distant mets: lung, liver, bone, skin. (<5%)
Rectal cancer surgery indication
Stage 3
- T1-2, N1-2, M0
- T3-4, N, M0
Risks of surgery treatment in colorectal cancer
- Infection, bleeding
- DVT/PE
- Injuries to other structures: bowel, bladder, ureter, vessels, pelvic nerves
- Anastomotic leak.
- MI/CVA/ Resp/ AKI
- Recurrence
- Chronic pain
- Lower anterior resection syndrome: incontinence, faecal urgency, diarrhoea, flatulence, abdominal pain.
Chemo and radiotherapy for colorectal cancer
Can be neoadjuvant/ adjuvant. 3 months/ 6 months.
- Drugs: FOLFOX/ FOLFIRI.;
- Only offered in rectal cancer stages (stage 3): T1-2, N1-2, M0 or T3-4, N, M0.
- Offered in colon stages(preoperative): T4
Advantages of CT colonoscopy
Not invasive
Can look outside the bowel
- Look at the distant disease
- I.e lymphadenopathy and metastasis
CEA test
- Descripton
- Causes of raised CEA
Blood test that is a tumour marker
- Used to monitor disease prolapse
CarinoEmbryonicAntigen
Non specific, raised in
- Smokers
- Ca prostate, ovary, lung, thyroid, liver cirrhosis.
FOB
- Collecting samples
faecal occult blood test
- Gold standard
- Picks up any blood in faeces
- Needs 3 separate samples from separate bowel movements
FIT test
Faecal immunochemical test
Picks up HUMAn blood in faeces
- More specific than FOB
Polyps
- Description
- Types (morphology)
- Malignancy tendency
- Management
Benign adenomas
- Excess growth of epithelium
Types
- Villous
- Tubular
- Tubulovillous
if >2cm= 40% chance of malignancy
<1cm= 1% chance of malignancy.
Management
- Medical: regular OGD and surveillance
- Surgical: protocolectomy/ colectomy
Symptoms of big colonic polyps
Bowel changes
- Constipation/ Bowel obstruction
- Watery faeces
Feeling of Incomplete evacuation (tenesmus)
- Esp if in rectrum
- Can present with haemorrhoids
PR bleed
Prolapse
- If the poly is low in rectum and pedunculated.
Treatment of big colonic polyps
Transanal endoscopic microsurgery (TEMS)
Transanal minimally invasive surgery (TAMIS)
Open/ Lap/ robotic
Colonoscopic endoscopic surgery
- Endoscopic mucosal resection (EMR)
- If polyp is confined to mucosa
- ESD- if polyp extends to sumucosa
Complications of laparoscopic surgery
Perforation
- Especially when putting in the first port
Organ injury
- i.e liver, vascular
Risks of surgery
Infection
Bleeding
DVT/ PE
Injury to bowel/ bladder/ nerves/ vessels
Anastomotic leak
Recurrence
Bowel ischaemia
- Presentation
- Causes
- Diagnosis
Presents
- Severe abdominal pain
- Nausea, vomitting
Causes
- Clot (from AF, from other areas)
Diagnosis
- CT angiogram
Colonic adenoma
- Description
- Classifications
- Presentation
- Malignant potential
Benign precursor of cororectal caricinoma
- Dysplastic epithelium
Classification
- Tubular: tubular glands
- Villous
- Tubulovillous (mixture)
Presentation
- Mainly asymptomatic
- If large, can bleed= Fe def anaemia
- Villous= hypoK, Hypoproteinaemia
Malignant potential
- Increases with size
- Increased dysplasia
APC
- Function
- Mutation
Tumour suppressor protein
- Degrades beta-catenin
- Prevents overstimulation of cell division
Mutation
- Causes increase in beta-catenin= increased transcription of genes that promote cell proliferation
- Associated with FAP and also in non-inherited colorectal cancer ( Caricnoma sequence)
Colorectal cancer types
- Pathology
Adenocarcinoma
- Mucinous
- Signet ring cell
- Anaplastic
Cancer morphology
Majority on left side of colon/ rectum.
- Rectum= most common
- Descending sigmoid (next common)
Clinical presentation
PR bleeding
- Deep red, on the surface of stools= rectal
- Dark red, mixed with stool= descending sigmoid
Iron-deficiency anaemia
- Right sided colon
Change in bowel habit
Emergency presentation of CRCa
Large bowel obstruction
- Colicky pain
- No BO
- Bloating
Perforation, peritonitis
Acute PR bleed
Curative treatment for CRCa
Surgical resection (with lymphadenectomy)
- Hemicolectomy
- High/ low anterior resection
- Anorectal resection
Low anterior resection
- Description
- Complications
- Indications
Removal of all/part of the rectum
- Anal-lower colon anastomosis (ultra-low, no remaining rectum) or
- Anal- rectum anastomosis
The lower the anastomosis, the higher risk of complications
- Anastomosis leakage
- Can be avoided via loop ileostomy
Indications
- Rectal carcinoma
- Rectal adenoma
- Sever anorectal sepsis
Ileoanal pouch
- Description
- Types
- Indication
Formation of a pouch from ileum when colon+rectum are removed but anus is preserved
- Allows rectal function to be retained.
Types
- J pouch (2 folds)
- W pouch (3 folds)
Indications
- Refractory UC
- FAP/ multiple colorectal polyposis
- Multiple colonic tumours including the rectum.
Complications of pelvic anastomosis (4)
Leakage
- Higher in lower anastomosis
Ischaemia
- Proximal bowel in anastomosis becomes ischaemic
Stenosis
- Later complication
- Treated with dilation under anaesthetic
Bleeding
Familial adenomatous polyposis
- Genetics
- Features
Autosomal dominant defect in APC gene
- Causes dozens-thousands of adenomatous polyps in colorectum
- Increased overall risk of colorectal cancer due to the number of polyps present.
Hereditary non-polyposis colorectal cancer (HNPCC)
- Genetics
-
Cancer syndrome also known as Lynch Syndrome
Autosomal dominant
- High risk of colon cancer (as well as ovary, stomach, brain, skin, hepatobillary)
- Mutations in DNA mismatch repair genes (MMR)
- Predisposes to adenoma
- Microsatellite instability
Staging investigations
- Local
- Metastasis
- Synchronous tumour
Local
- CT
- Rectal (Pelvic MRI)
Mets
- TAP CT
Syndronous tumour
- Colonoscopy, barium enema
