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Colorectal Carcinoma (CRC) (Risk Factors (Alcohol and smoking, Obesity,…
Colorectal Carcinoma (CRC)
Epidemiology
Majority occur in DISTAL COLON
Majority of presentations are in those over 60 yrs
Usually adenocarcinoma
More common in MALES than females
3rd most common cancer worldwide
More common in Western countries than in Asia or Africa
Risk Factors
Alcohol and smoking
Obesity
Colorectal polyps
Adenomas
Sugar consumption
Ulcerative colitis
Saturated animal fat and red meat consumption
Family history
Low fibre diet
Familial adenomatous polyposis - autosomal dominant, adenomas at 16 & cancer develops at 39
Increasing age
Lynch syndrome - autosomal dominant, causes cancer development from adenomas to occur quicker
Reduce risk - vegetables, garlic, milk, exercise & low dose aspirin
Pathophysiology
Nearly all are adenocarcinoma
Polypoid mass with ulceration
Progression
Normal epithelium - adenoma - colorectal adenocarcinoma
Spreads by direct infiltration through the bowel wall then spread to lymphatic and blood vessels and metastasis to LIVER and LUNG
Clinical Presentation
Right sided carcinoma
Weight loss
Low haemoglobin
May be present with a mass
Abdominal pain
Usually asymptomatic until they present with iron deficiency anaemia
Left sided & sigmoid carcinoma
Alternation constipation and diarrhoea
Thin/altered stool
Diarrhoea
Change of bowel habit with blood and mucus in stools
Blood in/with stools
The closer the cancer is to the outside the more visible blood and mucus will be
Rectal carcinoma
Rectal bleeding and mucus
When cancer grows will have thinner stools and tenesmus (cramping rectal pain)
Distribution of colorectal carcinoma - MAJORITY IN DISTAL COLON
Emergency presentation
Obstruction (20%)
4 cardinal signs of obstruction
Colicky abdominal pain
Abdominal distension
Absolute constipation
Vomiting (frequent)
Differential Diagnosis
Colonic pathology
Diverticular disease, IBD, ischaemic colitis
Small intestine and stomach pathology
Massive upper GI bleed - haematochezia
Meckel's diverticulum
Anorectal pathology
Haemorrhoids, anal fissure, anal prolapse
Diagnosis
Double contrast barium enema
CT colonoscopy
Limited in detecting small lesions but good at excluding cancer
Colonoscopy
GOLD STANDARD, allows for biopsy & removal of polyps
MRI to determine spread, done in all rectal cancers
Tumour markers e.g. CEA - not specific enough, useful for follow up & screening
Classification
Dukes Classification
TNM system
Faecal occult blood (FOB) - used in screening
Treatment
Radiotherapy
Palliation for colonic cancer
Used pre-op in rectal cancer
Chemotherapy
If Dukes C then give chemo post-op - reduce risk of death
Endoscopic stenting
For palliation in malignant obstruction
Decreases need for colostomy
Treated differently
Polyp cancers - removed with colonoscopy
Rectal cancer - chemotherapy pre-op to shrink tumour as hard to excise
Surgery
Only indicated if there is no metastasis
Open - hemicolectomy, colectomy or anterior resection
Only chance at cure
Laproscopic - less time in hospital, just as safe and same results