Colorectal Cancer

Basics

  • In the UK it is the third most prevalent cancer
  • Increased risk with family history, other cancers, age, inflammatory bowel disease, and diet (red meat, low fibre)

 

Symptoms

  • Change in bowel habit (usually to more loose and frequent stools)
  • Weight loss
  • PR bleeding
  • Tenesmus (feeling of full rectum even after opening bowels)
  • Iron Deficiency Anaemia (microcytic anaemia with low ferritin)
  • Bowel obstruction

N.B. Iron deficiency anaemia on its own without any other explanation (i.e. heavy menstruation) is an indication for a Two Week Wait cancer referral for colonoscopy and OGD (“top and tail”) for GI malignancy. This is because GI malignancies such as bowel cancer can cause microscopic bleeding (not visible on stools) that eventually lead to iron deficiency anaemia.

 

Investigation

  • Colonoscopy
    • Endoscopy to visualize full colon
    • Gold standard investigation
    • Can include biopsy or tattooing (to mark for surgery) of suspicious lesions
  • CT colonography
    • CT with bowel prep and contrast to visualize the colon
    • Consider in patient less fit for colonoscopy
  • Staging CT scan
    • CT Thorax Abdomen and Pelvis
    • To look for metastasis or other cancers
    • Consider in patients with weight loss in addition to colonoscopy as initial investigation to exclude other cancers
  • Carcinomembryonic Antigen (CEA)
    • Tumour marker blood test for bowel cancer
    • Not useful in screening
    • Useful in predicting relapse of previously treated bowel cancer

 

Dukes Classification

  • Dukes A – confined to mucosa and part of the muscle of the bowel wall
  • Dukes B – extending through the muscle of the bowel wall
  • Dukes C – lymph node involvement
  • Dukes D – metastatic disease

 

Dukes is being replaced by the TNM classification

T (tumour)

  • TX – unable to assess size
  • T1 – submucosal involvement
  • T2 – involvement of muscularis propria
  • T3 – involvement of the subserosa
  • T4 – spread directly to other tissues / peritoneum

N (nodes)

  • NX – unable to assess nodes
  • N0 – no nodal spread
  • N1 – spread to 1-3 nodes
  • N2 – spread to >3 nodes

M (metastasis)

  • M0 – no petastasis
  • M1 – metastasis

 

Treatment

  • Decision taken by MDT
  • Based on clinical condition, general health, staging radiography, histology and patient wishes
  • Options are surgical resection, chemotherapy, radiotherapy and palliation in any combination

 

Principles of bowel cancer resection

  • Colectomy can be curative or palliative
  • Laparoscopic approaches give better recovery and fewer complications
  • Involves removing the tumours and creating an end to end anastomosis (chopping out bowel and sewing the remaining bits together)

 

Covering Loop Ileostomy

  • A temporary ileostomy created to protect a distal anastomosis
  • Typically left for 6-8 weeks to allow healing of the anastomosis, after which is it reversed
  • “Loop” refers to it being the two ends (proximal and distal) of a section of small bowel being brought out onto skin
  • Proximal end (the productive side) has turned inside out to form a spout to protect the surrounding skin
  • Usually located lower right side of abdomen

 

Complications

  • Bleeding / infection / pain
  • Damage to nerves, bladder, ureter or bowel
  • Post op ileus
  • Anaesthetic risks
  • Conversion to open
  • Anastomotic leak / failure
  • Requirement for a stoma
  • Failure to remove the tumour
  • DVT/PE
  • Hernias
  • Adhesions

 

Operations

Right Hemicolectomy is used to remove tumours of the caecum, ascending and proximal transverse colon:

Left Hemicolectomy is used to remove tumours of the distal transverse and descending colon:

Sigmoid Colectomy is used to remove tumours of the sigmoid colon:

Anterior Resection is used to remove tumours of the low sigmoid colon or higher rectum:

Abdominoperineal Resection (APR) is used to remove tumours of the lower rectum. It requires removing the rectum and anus (plus or minus the sigmoid colon) and suturing over the anus. It leaves the patient with a permanent colostomy:

 

Follow-up to Curative Resections

  • CT T.A.P. at 1 and 2 or 3 years
  • Colonoscopy at 1 and 5 years
  • CEA 6 monthly for 3 years
  • Thereafter based on local policy
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