colorectal cancer Flashcards
Risk factors for colorectal cancer
diet rich in animal fats and low in fibre
IBD - UC
Familila associationnHNPCC FAP Gardener syndrome and APC
what gene causes bengin adenomas
APC
which gene causes the progression to invasive carcinoma
p53 DCC ras
decribe the progression from normal epithelium to invasive carcinoma
normal epithelium
hyperproliferative epithelium
benign adenomas
invasive carcinoma
an be caused by carcinogens in faeces prlonged time in the gut caused by low fibre diets can exacerbate this
Commonest colorectal cancer cell type
epithelial
Presentation of colorectal cancer
altered bowel habit, weight loss rectal bleed and vague abdominal pain
present with iron def anemia
investigations for colorectal cancer
rectal examination ridgid sigmoidoscopy - visualise bowel flexible sigmoidoscopy to get a biopsy double contrast enema for istology CT for staging - ct colonography combines ct scanning with insufflation fo the whole colon with gas - where colonoscopy is CI serum tumour marker CEA
Dukes staging
A- invasion into but not onto the bowel wall
B - through bowel wall
C- lymph node involved
D- distatnt mets
Managemnt of colorectal cancer
surgery
radiotherapy
chemo
when is surgery used
radical resection - in those with primary colorectal carcinoma
if mets to liver they can be removed too
surgery or colonic stenting can also be used in palliative to prevent obstructuve lesion
When is radiotherapy used
rectal carcinoma only as in other areas of the colon there is a risk of potential toxicity to adjacent organs
rectal carcinoma can be used pre operatively or following surgery but rare
local recurrance can be palliated with radio and metastatic disease can also respond to palliation
when is chemotherapy used
high risk colorectal cancer dukes c
test for 5 fu in dukes B and give chemo if present
oxpatin and irenoectan
what is a poor progonstic factor
being less than 40 years old
what type of screening is used
faecal occult blood testing has demonstrated a edution in mortality
