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Colorectal Cancer

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Screening podcast
Liver resections podcast
Large Bowel Obstruction podcast

1. Incidence

• Third most common form of cancer
• Second leading cause of cancer-related death in the Western World
• 16,000 deaths deaths per year in the UK
• 655,000 deaths worldwide per year.
• Lifetime risk - 1 in 22

2. Symptoms

• Change in bowel habit - change in either frequency, quality or consistency
• PR bleeding (for further reading on altered bowel habit and PR bleeding click here)
• Tenesmus
• Symptoms of Anaemia
• Abdominal Mass
• Weight Loss

3. Risk Factors

• diet - high in red meat, low in fruit, vegetables and fibre
• smoking
• Family history of colon cancer
• Long-standing IBD - approx 30% after 25 years if total colitis
• Ureterosigmoidostomy
• Previous gastric surgery
• Hereditary conditions -
• Familial Adenomatous Polyposis
• Hereditary Non-Polyposis Colorectal Cancer
• Gardner's Syndrome
• Turcot's syndrome
• Canada-Cronkhite syndrome

4. Diagnosis (click on pictures to enlarge)

History and Examination Digital Rectal Exam (DRE): detection of tumours in the distal rectum Rigid Sigmoidoscopy Proctoscopy Bloods: detection of presence of iron deficiency anaemia + liver function for mets Double contrast barium enema: First, an overnight preparation is taken to cleanse the colon. An enema containing barium sulfate is administered, then air is insufflated into the colon, distending it. The result is a thin layer of barium over the inner lining of the colon which is visible on X-ray films. A cancer or a precancerous polyp can be detected this way. This technique can miss the (less common) flat polyp. Sigmoidoscopy/Colonoscopy - Advantage over barium enema as polyps discovered can be removed + tissue can be taken for biopsy To see the beating bowel cancer website from a patients perspective on bowel cancer click here

5. Bowel Cancer Screening

• The NHS Bowel Cancer Screening Programme is now being rolled out nationally and will achievenationwide coverage by 2009.
• The NHS Bowel Cancer Screening Programme offers screening every two years to all men and women aged 60 to 69.
• The programme will offer Faecal Occult Blood (FOB) stool test
• Aims to detect bowel cancer at an early stage (in people with no symptoms), when treatment is more likely to be effective.
• Only 2 out of every 100 will have an abnormal result and proceed to colonoscopy
• A lot of "false positives" with FOB's. Only about 6 out of every 100 with a single positive FOB will have cancer.
• For further reading on bowel cancer screening and screening of high risk groups click here

6. Imaging

Computed Tomography (CT) chest/abdo/pelvis

• On detection of a colonic cancer a CT scan is ordered for the detection of metastases tolung/liver/intraperitoneal

Magnetic Resonance Imaging (MRI) pelvis

• Used for staging rectal cancer and determining local extension of tumour

7. Pathology

7.1 Macroscopic

7.2 Microscopic

• 95% adenocarcinoma
• Other rare types include SCC and lymphoma

Spread of colon cancer

• Direct  - local extension
• Lymphatic's - predominant mode of metastasis. Spreads from paracolic nodes along main colic arteries to reach para-aortic glands.
• Blood - most common blood-bourne site is by portal spread to the liver
• Trans-coelomically

8. Staging systems

Dukes

Dukes Stage	Histology	Prognosis (5 Year Survival)
A	Not breached muscularis propria	90%
B	Breached muscularis propria	70%
C1	(apical node negative)	60%
C2	(apical node positive)	35%
D	distant metastases	5%

Other modifications have been described, including the TNM systems (Tumour, Node, Metastasis)

Tumour

• T1: Tumor invades submucosa
• T2: Tumor invades muscularis propria.
• T3: Tumor invades through the muscularis propria into the subserosa, or into the pericolic or perirectal tissues
• T4: Tumor directly invades other organs or structures, and/or perforates.

Node

• N0: No regional lymph node metastasis
• N1: Metastasis in 1 to 3 regional lymph nodes
• N2: Metastasis in 4 or more regional lymph nodes

Metastasis

• M0: No distant metastasis
• M1: Distant metastasis present




 

9. Treatment

 

• Depends on staging
• Surgery is primary treatment while chemotherapy and/or radiotherapy may be recommended depending on patient's staging and other medical factors.

 

9.1 Surgery

 

Categorise into:

• curative
• palliative
• bypass
• faecal diversion

 

9.1.1 Curative

• Colonic cancer resection requires 5 cm proximal and  2 cm distal clearance from the lesion
• For Anterior resection for rectal carcinoma, if the total mesorectal excision is performed, only 1 cm distal clearance of rectal lesions is required

Right Hemicolectomy

• Performed for tumours of the ascending colon to distal transverse colon
• Due to the variable blood supply of the distal transverse colon, resection must include the entire colon supplied by the ileocolic and middle colic arteries to obtain histological clearance.
• To see a video of a laparoscopic assisted right hemicolectomy click here

 

Left Hemicolectomy

• Performed for tumours of the descending colon

 

Anterior Resection

• Performed for rectal tumours
• Classified as high, low, or extended low, depending on the extent of rectal mobilization and resection and on the level of the restorative anastomosis.
• For further reading on the technique of anterior resection with total mesorectal excision click here

 

Abdomino-Perineal Resection

• 4cm or less from the anal verge.
• Although ultra-low sphincter conserving anterior resection is possible other patient factors need to be considered carefully such as patient age, mobility and pre-operative sphincter control.

 

9.1.2 Palliative

• Offered in the case of multiple mets
• palliative resection is still offered to reduce further morbidity by eg tumour invasion or bleeding
• If resection is not feasible due to to co-morbid status or an inoperable obstructing lesion then a stent can be placed across the tumour to palliate symptoms .
• Click here to see the procedure of colonic stenting

 

9.1.3 Bypass and faecal diversion

• performed if tumour is invading into adjacent structures making excision difficult

 

9.2 Treatment of Liver Metastases

• Podcast

  An audio podcast about liver metastases and resections Length: 6 mins     Filesize: 6Mb Download podcast (mp3) (right click and use 'Save as...' to download) Or stream from here:



• 30% have metastatic deposits in the liver at time of presentation.
• Role of surgery for liver mets - Careful selection is required in all cases. Extensive resections performed as long as clear tumour resection margins can be achieved and at least 60% normal functioning liver is left behind. Most widely accepted criterion for resection is one to three resectable mets in one lobe of the liver.
• 25% 5-year survival rate after hepatic resection with clear margins.
• for further reading on guidelines on resection of colorectal cancer liver metastases click here

 

10. Risk factors for local recurrence following resection?

• Tumour penetration of the bowel wall
• Lymph node involvement
• High histological grade
• Diminished lymphatic reaction
• Neurovascular invasion
• Tumour perforation
• Bowel obstruction
• Direct invasion of adjacent organs

 

11. Flow Chart for suggested management and follow up of colorectal cancer



 

• For further reading on follow up of patients with colorectal adenomas and cancer see below

 

11.1 CEA (Carcinoembryonic antigen)

• Tumour marker useful for the monitoring for evidence of recurrence
• Less likely to be elevated in poorly differentiated cancers or rectal cancers
• CEA is elevated in a number of other gastrointestinal conditions e.g. pancreatic cancer or HPB disease and therefore if elevated post-operatively does not necessarily mean colorectal cancer recurrence
• CEA does not have to be elevated for recurrence to be present
• Therefore follow up colonoscopy and imaging must be used in conjunction
• CEA is also useful for the monitoring of patients undergoing chemotherapy. CEA would fall if the tumour were responding to treatment

12. Suggested further reading

BSG guidelines for resection of colorectal cancer liver metastases
http://www.bsg.org.uk/pdf_word_docs/liver_metastases.pdf
BSG guidelines for colonoscopy follow up after resection of colorectal cancer
http://www.bsg.org.uk/pdf_word_docs/ccs2.pdf
Beating bowel cancer website
http://www.beatingbowelcancer.org

Summary of recommendations for colorectal cancer screening and surveillance in high risk groups
http://www.bsg.org.uk/pdf_word_docs/ccs9.pdf
Royal College of Surgeons of Edinburgh e-learning module on altered bowel habit and PR bleeding
http://www.rcsed.ac.uk/eselect/sig1.htm
Royal College of Surgeons of Edinburgh e-learning module on anterior resection with total mesorectal excision
http://www.edu.rcsed.ac.uk/HowIDoIt/Anterior%20resection%20with%20total%20mesorectal%20excision.htm
Papers by RJ Heald on TME dissection for rectal cancer, Mesorectal excision for rectal cancer
http://www.ncbi.nlm.nih.gov/pubmed/8094488
Effect of the introduction of total mesorectal excision for the treatment of rectal cancer
http://www3.interscience.wiley.com/cgi-bin/fulltext/102525965/PDFSTART


8. Follow up after Colorectal Surgery (FACS) trial website and information

FACS
http://www.facs.soton.ac.uk/
BSG
http://www.bsg.org.uk/pdf_word_docs/complications.pdf