Bowel Cancer
Epidemiology
most common cancer in AU, incidence increases greatly with age, mostly adenocarcinomas
Risk factors
neplastic polyps, IBD, genetic disposition (FAP, HNPCC, strong FHx), poor diet, ETOH, smoking, previous cancer
Pathophysiology
Poor prognostic factors
Rectosigmoidal tumors - early spread to lungs via paravertebral venous drainage; CEA >5, poor differentiation, bowel perforation, venous invasion, adherence to adjacent organs etc
Staging
TNM, Dukes classification
Clinical Features
most common cancer in AU, incidence increases greatly with age, mostly adenocarcinomas
Risk factors
neplastic polyps, IBD, genetic disposition (FAP, HNPCC, strong FHx), poor diet, ETOH, smoking, previous cancer
Pathophysiology
- polyps —> dysplasia —> carcinoma in situ —> carcinoma
- point mutation in Kras protooncogene, hypomethylation, allelic loss at APC and DCC gene on chromosome 18 and mutation of p53 (tumor suppressor gene) at chromosome 17
- mostly adenocarcinoma, 75% distal to splenic flexure
- Spreads via local invasion, lymphatic, blood (liver, lung, bone) or transcolemic
Poor prognostic factors
Rectosigmoidal tumors - early spread to lungs via paravertebral venous drainage; CEA >5, poor differentiation, bowel perforation, venous invasion, adherence to adjacent organs etc
Staging
TNM, Dukes classification
Clinical Features
Investigations
Management
Prognosis:
- Bloods: FBC (microcytic anaemia), LFT, CEA
- Others: Faecal occult blood, sigmoidoscopy, barium enema, colonoscopy, USS liver, CT
Management
- Surgery - open vs laparoscopic, +/- stenting
- R hemicolectomy (caecal, ascending, proximal transverse)
- L hemicolectomy (distal transverse or descending colon
- Sigmoid colectomy (sigmoid)
- Anterior resection (low sigmoid or high rectal tumour)
- Hartmann’s procedure (emergency bowel obstruction, perforation or palliation
- Radiotherapy - mainly used for palliation, tumours with high risk of recurrence, debulking for resection
- Chemotherapy
Prognosis:
- Screening programme: 50 - 65yo, offered every 5 years, biennial FOBT
Source
OHCM 9th Ed 2014
Harrisons 18th Ed 2012