Large Bowel Tumours

Classification

Tumour – n. abnormal swelling in or on a part of the body, usually applied to an abnormal growth of tissue.

Benign

  • Adenomatous polyp -->
  • Papilloma
  • Lipoma
  • Neurofibroma
  • Haemangioma

Malignant

  • Primary:
    • Carcinoma -->
    • Lymphoma
    • Carcinoid tumour
    • Secondary:
      • Invasion from adjacent tumours
        • Stomach, bladder, uterus, ovary

 

Carcinoma

  • Large bowel carcinoma is common
    • Second most common cause of death from malignant disease in UK after:
      • Lung malignancy in men
      • Breast malignancy in women
      • Women more affected
      • Sigmoid – most common site
        • Rectum – 1/3 of all large bowel malignancies
        • 5% are multiple (synchronous)

 

Predisposing factors

  • Pre-existing polyps
  • Ulcerative colitis
  • Various inherited colorectal cancer syndromes
    • Familial adenomatous polyposis
    • Hereditary non-polyposis colon cancer
    • Family history
      • Normal lifetime risk – 1/50
      • 1 first-degree relative diagnosed >45 yrs – 1/17
      • 1 first-degree relative diagnosed <45 yrs – 1/10

 

Familial adenomatous polyposis

  • 0.5% colon cancers
  • Autosomal dominant inheritance
    • Mutation in familial adenomatous polyposis (FAP) gene
    • Polyps appear in adolescence
      • Bleeding and diarrhoea – 21yrs
      • Malignant change – 20-40 yrs
      • Affected individual – hypertrophy of retinal pigment layer
        • Useful non-invasive test
        • Variants exist, including Gardner’s syndrome
        • Treatment:
          • Total colectomy with excision of rectum
          • Formation of ileo-anal pouch

 

Hereditary non-polyposis colon cancer

  • 5% colon cancers
  • Autosomal dominant inheritance
    • Gene mutation affecting DNA mismatch repair
    • Leads to genomic instability
    • Tumours occur in right colon
    • Arise <50 yrs
    • Occurrence of colon cancer in 3 family members spanning 2 generation <50 yrs suggests this syndrome
    • Also associated with tumours of the:
      • Ovary
      • Uterus
      • Stomach

 

Pathology

  • Macroscopically, classified:
    • Papilliferous
    • Malignant ulcer
    • Annular
    • Diffuse infiltrating growth
    • Mucinous tumour
    • Microscopically:
      • All adenocarcinomas

 

Spread

  • Local:
    • Encircling bowel wall and invading coats of colon
    • Eventual involvement of adjacent viscera
      • Small intestine, stomach, duodenum, ureter, bladder, uterus, abdominal wall etc.
      • Lymphatic:
        • Regional lymph nodes
        • Eventually spreading via thoracic duct
        • May involve supraclavicular nodes in late cases
        • Bloodstream:
          • Liver via portal vein, then to lung
          • Transcoelomic:
            • Producing deposits of malignant nodules throughout peritoneal cavity

 

Staging

  • Traditionally Dukes’ classification
  • TNM more commonly used nowadays
    • T – size of tumour and invasion
      • Tx – tumour cannot be evaluated
      • Tis – carcinoma in situ
      • T0 – no signs of tumour
      • T1, T2, T3, T4 – size/extent of tumour
  • N – regional lymph node involvement
    • Nx – cannot be evaluated
    • N0 – absent from regional nodes
    • N1 – regional lymph node mets present
    • N2 – tumour spread to an extent between N1 and N3
    • N3 – tumour spread to more distant or numerous regional nodes
  • M – distant metastases
    • Mx – cannot be evaluated
    • M0 – no distant metastases
    • M1 – mets to distant organs (beyond regional nodes)

Clinical features

  • Divided
    • Produced by tumour itself
    • Arising from presence of secondaries
    • General affects of the tumour

 

Local effects

  • Change in bowel habit
    • Most common
    • Constipation, diarrhoea, or fluctuation between the two
    • Intestinal obstruction
      • Constricting neoplasm (commonly left (descending) colon)
      • Perforation of the tumour
        •                         Either into general peritoneal cavity or locally with abscess or fistula formation

 

Effects of secondary deposits

  • Jaundice
  • Abdominal distension due to ascites
  • Hepatomegaly

 

General effects of malignant disease

  • Anaemia, anorexia, weight loss

 

Examination

Seek evidence of:

  • Palpable mass
  • Clinical evidence of obstruction
  • Evidence of spread
    • Hepatomegaly, ascites, jaundice, supraclavicular lymphadenopathy
  • Clinical evidence of anaemia or loss of weight

Special investigation

  • Sigmoidoscopy
    • Evidence of tumour – biopsy
    • More proximal tumours – evidence of blood/slime coming down from above
    • Colonoscopy
    • Barium enema
      • Stricture or filling defect
        • ‘apple core’ deformity (image)
        • CT
          • Useful for elderly patients who tolerate bowel preparation poorly

Differential diagnosis

  • Diseases producing local symptoms
    • Diverticular disease
    • UC
    • Dysenteris and other causes of diarrhoea and constipation

 

Treatment

  • Preoperative
    • Clear bowel
      • Enema
      • Picolax
  • Metronidazole and gentamicin (or a cephalosporin)
  • Hb level checked
  • Operative
    • Wide resection of the growth and its regional lymphatics
    • Unobstructed – prior preparation, primary resection and restoration of continuity
    • Obstructed – preparation contraindicated, primary goal to relieve obstruction
    • Postoperative
      • Adjuvant chemotherapy – 5-fluorouracil (5-FU) in combination with folinic acid
      • Metastatic disease – add irinotecan
      • Follow-up cross-sectional imaging
        • Detect local recurrence/liver mets
        • Follow-up surveillance colonoscopy