Colorectal carcinoma

  • Colorectal cancer is second commonest cancer causing death in the UK
  • 20,000 new cases per year in UK - 40% rectal and 60% colonic
  • 3% patients present with more than one tumour (=synchronous tumours)
  • A previous colonic neoplasm increases the risk of a second tumour (=metachronous tumour)
  • Some cases are hereditary
  • Most related to environmental factors - dietary red fat and animal fat

Adenoma - carcinoma sequence

  • Of all adenomas - 70% tubular, 10% villous and 20% tubulovillous 
  • Most cancers believed to arise within pre-existing adenomas
  • Risk of cancer greatest in villous adenoma
  • Series of mutations results in epithelial changes from normality, through dysplasia to invasion
  • Important genes - APC, DCC, k-ras, p53.

Clinical presentation

  • Right-sided lesions present with
    • Iron deficiency anaemia due occult GI Blood loss
    • Weight loss
    • Right iliac fossa mass
  • Left-sided lesions present with
    • Abdominal pain
    • Alteration in bowel habit
    • Rectal bleeding
  • 40% of cancers present as a surgical emergency with either obstruction or perforation
  • Emergency presentation is associated with a poorer outcome

A low rectal carcinoma

Picture supplied by Mr N P J Cripps, Consultant Colorectal Surgeon, Chichester, United Kingdom

Intraoperative appearance of caecal carcinoma

Picture provided by Mr David Anderson, St John's Hospital, Livingston, Scotland

Investigation

  • In elective cases diagnosis can be confirmed by a combination of:
    • Rigid sigmoidoscopy
    • Flexible sigmoidoscopy
    • Colonoscopy
    • Double contrast barium enema
  • In patients presenting with large bowel obstruction single contrast enema (after rigid sigmoidoscopy) is the investigation of choice

Double contrast barium enema showing an apple-core stricture

Endoscopic apperance of sigmoid carcinoma

Surgical options

  • Any surgical resection requires 5 cm proximal and  2 cm distal clearance for colonic lesions
  • 1 cm distal clearance of rectal lesions adequate if mesorectum resected
  • Radial margin should be histopathologically free of tumour if possible
  • Lymph node resection should be performed to the origin of the feeding vessel
  • En Bloc resection of adherent tumours should be performed
  • The value of a 'no-touch' techniques remains unproven
  • Depending on site of lesion surgical options are:
    • Caecum, ascending colon, hepatic flexure Right hemicolectomy
    • Transverse colon Extended right hemicolectomy
    • Splenic flexure, descending colon Left hemicolectomy
    • Sigmoid colon High anterior resection
    • Upper rectum Anterior resection
  • Consider defunctioning loop ileostomy is anastomosis <12 cm from anal margin
    • Lower rectum Abdomino-perineal resection
    • Small lower rectal cancers may be resectable by transanal microsurgery
  • Laparoscopic surgery is unproven
  • Early studies raised concerns about port site recurrence
  • Recent studies suggest equivalent overall and disease-free survival

Surgery for upper rectal cancers

  • Risk of local recurrence reduced by performing total mesorectal excision (TME)
  • Pelvic peritoneum and lateral ligaments divides
  • Plane between visceral (rectum, mesorectum) and somatic structures dissected

Anatomy of the mesorectum

  • Middle rectal vessels divided laterally
  • Rectal stump washed out with cytocidal fluid (water, Betadine) from below.

Total mesorectal operative specimen

Picture provided by Prof Ian Bradford, Prince of Wales Hospital, Shatin, Hong Kong

Dukes Classification

  • Developed by Cuthbert Duke in 1932 for rectal cancers
  • Dukes staging of colorectal cancer

Duke's stageing of colorectal cancer

  • Stage A - Tumour confined to the mucosa
  • Stage B - Tumour infiltrating through muscle
  • Stage C - Lymph node metastases present
  • Five year survival - 90%, 70% and 30% for Stages A, B and C respectively

Adjuvant radiotherapy

  • In patients with rectal cancer 50% undergoing curative resection develop local recurrence
  • Median survival with local recurrence is less than one year
  • Risk factors for local recurrence include:
    • Local extent of tumour
    • Nodal involvement
    • Circumferential margin status
  • Risk of local recurrence can be reduced by radiotherapy
  • Can be given either preoperatively or postoperatively
  • Preoperative radiotherapy given as short course immediately prior to surgery
    • Reduces local recurrence
    • Increases time to recurrence
    • Improves 5-year survival
  • Combination chemotherapy and radiotherapy may produce better outcome

Adjuvant chemotherapy

  • Improves survival in Duke's C tumours
  • Not required in Duke's A tumours which already have a good prognosis
  • Role in Duke's B tumours remains to be defined
  • Currently being investigated in the QUASAR (Quick and Simple and Reliable) trial
  • Results of QUASAR study to date have shown
    • 5FU and folinic acid is effective as adjuvant therapy
    • High dose folinic acid rescue confers no additional benefit
    • The use of levimasole confers no additional benefit

Colorectal cancer screening

  • Screening for colorectal cancer can be divided into two categories
    • Screening of high risk groups
    • Population screening

Screening of high risk groups

  • This includes
    • Patients with family history
    • Sporadic adenomatous polyps
    • Inflammatory bowel disease
  • Definition of the high risk group is difficult
  • High risk patients should undergo colonoscopy at approximately 50 years
  • Patients with family history of FAP or HNPCC should undergo genetic testing
  • If mutation present should undergo intensive colonoscopic screening from adolescence

Population screening

  • The role of screening is currently being investigated by either
    • Faecal occult blood testing
    • Colonoscopy
  • Nottingham study has recruited over 150,000 patients
  • 75,250 underwent biennial FOB testing
  • Resulted in 1774 colonoscopies
  • Seven complications occurred requiring operations in 6 patients
  • No difference identified in stage of presentation in screened group
  • Survival in screened group was significantly improved

Bibliography

Baigre R J, Berry A R.  Management of advanced rectal cancer.  Br J Surg 1994; 81: 343-352.

Banerjee A K.  Local excision of rectal cancers.  Br J Surg 1995; 82: 1165-1173.

Camma C,  Giunta M,  Fiorica F,  Pagliaro L,  Craxi A,  Cottone M.  Preoperative radiotherapy for resectable rectal cancer.  JAMA 2000;  284:  1008-1015.

Colorectal Cancer Collaborative Group.  Adjuvant radiotherapy for rectal cancer:  a systematic overview of 8507 patients from 22 randomised trials.  Lancet 2001;  358:  1291-1304.

Heald R J,  Karanja N D.  The management of colorectal cancer.  Curr Surg Pract 1993; 5:  195-201.

Huang A,  Hindle K S,  Tsavellas G.  Colorectal cancer surveillance post surgery.  Hosp Med 2001:  62:  490-491.

Leslie A,  Steele R J C.  Management of colorectal cancer.  Postgrad Med J 2002;  78:  473-478.

Leung K L,  Kwok S P Y,  Lam S C W.  Laparoscopic resection of rectosigmoid carcinoma:  prospective randomised trial.  Lancet 2004;  363:  1187-1192.

MacFarlane J K,  Ryall R D H,  Heald R J.  Mesorectal excision for rectal cancer.  Lancet 1993;  341:  457-460.

McArdle C S,  Hole D J.  Emergency presentation of colorectal cancer is associated with poor 5-year survival.  Br J Surg 2004;  91:  605-609.

Myint A S,  Carter P,  Hershman M J.  Improving outcome in rectal cancer.  Hosp Med 2000;  61:  706-710.

Nicholls R J, Hall C.  Treatment of non-disseminated cancer of the lower rectum.  Br J Surg 1996: 83:  15-8.

Nelson H,  Petrelli N,  Carlin A et al.  Guidelines 200 for colon and rectal cancer surgery.  J Natl Cancer Inst 2001;  93:  583-596.

Quasar Collaborative Group.  Comparison of flurouracil with additional levimasole, higher-dose folinic acid or both as adjuvant therapy for colorectal cancer:  a randomised trial.  Lancet 2000;  355:  1588-1596.

Rayter Z et al.  Adjuvant chemotherapy for colorectal cancer.  Ann R Coll Surg 1995; 77: 81-84.

Renehan A G,  Egger M,  Saunders M P,  O'Dwyer S T.  Impact on survival of intensive follow up after curative resection for colorectal cancer: systematic review and meta-analysis of randomised trials.  Br J Med 2002;  324:  1-8.

Robinson M H,  Hardcastle J D,  Moss S M et al.  The risks of screening:  data from the Nottingham randomised controlled trial of faecal occult blood screening for colorectal cancer.  Gut 1999;  45:  588-592.

Sagar P M.  Surgical management of locally recurrent rectal cancer.  Br J Surg 1996; 83: 293-304.

Steele R J C.  Anterior resection with total mesorectal excision.  J R Coll Surg Ed 1999;  44:  40-45.

 

 
 

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