Colon Cancers Flashcards
Risk factors for bowel cancer?
- Family history
- FAP
- HNPCC (Lynch syndrome)
- IBD
+ age, diet (↑red meat, ↓fibre), obesity, smoking and alcohol
What is Familial adenomatous polyposis (FAP)?
Autosomal dominant condition
Results in many polyps (adenomas) developing in the large intestine, which have the potential to become cancerous
What gene is mutated in FAP?
tumour suppressor genes called adenomatous polyposis coli (APC)
Treatment of FAP?
Prophylactic removal of the large intestine → panproctocolectomy
At what age does cancer due to FAP usually occur?
< 40yrs
What is Hereditary nonpolyposis colorectal cancer (HNPCC)?
ie. Lynch syndrome
Autosomal dominant condition which increases risk of a number of cancers, esp colorectal cancer
Unlike FAP it does not cause adenomas, tumours develop in isolation
What are the mutations in HNPCC?
In DNA mismatch repair (MMR)
List 4 reg flags for bowel cancer?
- Change in bowel habit (more loose, frequent stools)
- Unexplained weight loss
- Rectal bleeding
- Unexplained abdominal pain
- Iron deficiency anaemia
- Abdominal or rectal mass on examination
How may bowel cancer present? (Hint: red flags)
- Change in bowel habit (more loose, frequent stools)
- Unexplained weight loss
- Rectal bleeding
- Unexplained abdominal pain
- Iron deficiency anaemia
- Abdominal or rectal mass on examination
What type of anaemia is seen in bowel cancer?
Iron deficiency anaemia → microcytic anaemia with low ferritin
NICE two week wait referral criteria for suspected bowel cancer?
- Over 40 years + abdominal pain and unexplained weight loss
- Over 50 years + unexplained rectal bleeding
- Over 60 years + a change in bowel habit or iron deficiency anaemia
To whom is FIT testing offered?
To assess patients for bowel cancer that do not meet the two week wait referral criteria:
- Over 50 with unexplained weight loss and no other symptoms
- Under 60 with a change in bowel habit
Bowel cancer screening?
FIT testing offered to patients aged 60 – 74 years every 2 years
Screening for bowel cancer in patients with risk factors? (ie FAP, HNPCC or IBD)
Colonoscopy at regular intervals
Gold standard investigation for suspected bowel cancer?
Colonoscopy + biopsy
Other investigations for suspected bowel cancer?
- Sigmoidoscopy
- CT colonography
- Staging CT TAP
- Tumour marker blood tests (CEA)
What tumour marker may be raised in bowel cancer?
Carcinoembryonic antigen (CEA)
NOT helpful in screening, but may be used to predict relapse
What classification system was used for bowel cancer? (No longer used)
Explain
Dukes’
- A – confined to mucosa, part of the muscle in the bowel wall
- B – extends through muscle
- C – lymph node involvement
- D – metastatic disease
What classification is more commonly used to stage bowel cancer?
Explain
TNM classification
List 4 options for managing bowel cancer (in any combination)
- Surgical resection
- Chemotherapy
- Radiotherapy
- Palliative care
Surgery for bowel cancers involves what 4 steps?
- Identifying the tumour
- Removing section of bowel containing tumour
- creating an end-to-end anastomosis
- OR alternatively creating a stoma
What is a Right hemicolectomy?
Removal of the caecum, ascending and proximal transverse colon
What is a left hemicolectomy?
Removal of the distal transverse and descending colon
What is a High anterior resection?
Removing the sigmoid colon (sigmoid colectomy)
What is a Low anterior resection?
Removing the sigmoid colon and upper rectum but sparing the lower rectum and anus
What is a Abdomino-perineal resection (APR) ?
Removing the rectum and anus (plus or minus the sigmoid colon) and suturing over the anus
Leaves the patient with a permanent colostomy
Complications of bowel cancer surgery?
- Bleeding, infection and pain
- Damage to nerves, bladder, ureter or bowel
- Post-operative ileus
- Anaesthetic risks
What is Low Anterior Resection Syndrome?
May occur after resection of a portion of bowel from the rectum, with anastomosis between the colon and rectum
- Urgency and frequency of bowel movements
- Faecal incontinence
- Difficulty controlling flatulence
How long is the follow up period time following curative surgery?
3 years
List 2 common indications for a Hartmann’s procedure
- Acute obstruction by a tumour
- Significant diverticular disease
List 2 follow up investigations
- CEA
- CT TAP
What is a Hartmann’s procedure?
Usually an emergency procedure
Removal of the rectosigmoid colon and creation of an colostomy with closure of the anorectal stump ?
Colostomy may be permanent or reversed at a later date
