Colorectal CA Flashcards
colorectal CA
potentially life-threatening CA of the colon
etiology & risk factors
- idiopathic
- family hx of CA
- IBD
- aging (>50yrs)
- adenomatous polyposis
- poor diet (high fat and refined sugars)
why is having adenomatous polyposis a risk factor
a rare condition where an individual has multiple polyps formed on the epithelium of the large intestine and if left untreated can become malignant
why is having a diet with high fat content a risk factor
high fat content increases bile acid synthesis in the liver which may be converted into potential carcinogens by the bacterial flora in the colon
why is having a diet with high refined sugar content a risk factor
high refined sugar content enhances proliferation of bacterial organisms that convert bile acid into carcinogens
what is the protective role of aspirin against colorectal CA
- aspirin inhibits cyclooxygenase (COX-2) which limits production of prostaglandins
- aspirin suppresses cell proliferation by prostaglandin and reduces the risk of a tumor to develop
prostaglandins
promotes inflm and cell proliferation
cyclooxygenase (COX-2)
Es that converts arachidonic acid in cell membranes to prostaglandins
how many stages of colorectal CA
4
stage I of colorectal CA
- limited to invasion of mucosa and submucosa of the colon (first 2 layers)
- 5 yr survival rate of 90-100%
stage II of colorectal CA
- tumor infiltrates the muscularis externa
- no lymph node involvement
- 5 yr survival rate of 70-85%
stage III of colorectal CA
- tumor invades serosa and regional lymph nodes (lymph-node positive)
- 5 yr survival rate of 40-60%
stage IV of colorectal CA
- tumor penetrates serosa layer (all layers) and adjacent organs
- metastases occurs (ex. distant spread to liver)
- poor prognosis
mnfts
- usually late onset
- bleeding (early sympt)
- change in bowel habits (diarrhea, constipation)
- pain (late sympt)
dx
screenings: DRE (direct rectal examination) & fecal occult blood test (routine exam)
- barium enema
- sigmoidoscopy & colonoscopy
