Colorectal Cancer Flashcards
Define colorectal cancer?
Malignant adenocarcinoma of the large bowel
What is the distribution of colorectal cancers?
60% - rectum and sigmoid
30% - descending colon
10% - rest of colon
What are the causes of colorectal cancer?
Environmental and genetic
There is a sequence of genetic changes that go from normal bowel epithelium to cancer (e.g. APC, K-Ras)
What are the risk factors for colorectal cancer?
Western diet (e.g. red meat + alcohol) Colorectal polyps Previous colorectal cancer Family History IBD
What is the epidemiology of colorectal cancer?
Second Most Common cause of cancer death in the WEST
UK: 20,000 deaths per year
Average age of diagnosis: 60-65 years
What do the presenting symptoms of colorectal cancer depend on?
Size and location of the tumour
What are the presenting symptoms of left-sided colon and rectum?
Change in bowel habit
Rectal bleeding (blood or mucus mixed with the stools)
Tenesmus (due to a space-occupying tumour in the rectum)
What are the presenting symptoms of right-sided colon cancer?
Presents later Anaemia symptoms (lethargy) Weight Loss Non-specific malaise Lower abdominal pain (rare)
What’s important to remember with colorectal cancers?
20% of tumours will present as an emergency with pain and distention due to:
Large bowel obstruction
Haemorrhage or peritonitis due to perforation
What are the signs of colorectal cancer on physical examination?
Anaemia
Abdominal Mass
Low-lying rectal tumours may be palpable on DRE
What are the signs of colorectal cancer on physical examination if it’s metastatic?
Hepatomegaly
Ascites (shifting dullness)
What bloods would you do for colorectal cancer?
FBC - anaemia
LFTs
Tumour markers (CEA)
What investigation would you do with a person’s stool in colorectal cancer?
FOBT - used as a screening test
Why do we Endoscopy in colorectal cancer?
Sigmoidoscopy
Colonoscopy
This can be used to biopsy the tumour
What might we see if we do a Double-Contrast Barium Enema in colorectal cancer?
May show ‘apple core’ strictures
