colorectal cancer Flashcards
what is the most common malignancy in the gastrointestinal tract ?
colorectal cancer
third most common cancer of all
when is the peak incidence of CRC?
70 years
what are the types colorectal carcinomas ?
adenocarcinoma - 95 recent
carcinoid tumors - specialised hormone producing cells in intestine
GIST - intestinal cells of CAJAL
GIST are most usually in the colon
lymphomas
sarcoma - muscle and connective tissue of the wall of colon and rectum
very rare
what is the etiology of CRC ?
exogenous
smoking
obesity
red meat and animal fat
ulcerative colitis (sometime chrons disease)
colorectal adenoma
familial adenomatous polyposisi - by 20 age almost all have colorectal cancer
peutz jeghers syndrome
heridtory non polposi colon cancer / lynch syndrome (short interval to malignancy 2 years where normal 10-15 years)
hamartomatous syndromes
endocarditis and bacteria related to streptocoss gallolyticus
where is most colorectal carcinoma found ?
in rectum and sigmoid colon followed by colon ascended
what is the pathophysiology of colorectal adenocarcinoma ?
arises for adenomatous polyps
mutation in oncogenes and tumor suppressor genes - result to carcinoma
COX-2 over expression - related to colorectal carcinoma - that’s why PRVENTIVE MEASURES IF ASPIRIN AND NSAIDS
what are the types of non neoplastic colorectal polyps ?
types of polyps : adenomas - malignancy potential tubular tubulovillous villous
hyperplastic (highest occurrence and located in colorectal )
inflammatory
what are the prognostic malignant factors of polyps ?
size of polyp - more than 2 cm
type of polyp
tubular- most of the time
tubovillous
villous even lower - highest change of malignant (can cause hypkalemia and profusemucus discharge , serrated )
sessile (villous) or pedunulated
numer of polyps - more than 3
poor differentiation
site of polyp
vascular and lymphatic invasion
what is the prophylaxis of colorectal carcinoma >
screening
polyps takes 10-15 years for malignancy - colonoscopy at the age of 50 - negative then every 10 years
in higher risk = no later than 40
double contrast barium enema = good at fining cancer and polyps
adenomas removed with wire lopp or hot forceps
stool dna test
GUIAC fetal occult blood test fecal immunochemical test
COLOGUARD - sTOOL DNA TEST
blood tumor markers - ca 19-9
epiprocolon - blood based colorectal test
MICROSATELITE INSTABILITY TESTING
CALCIUM AND FOLATE AND FIBRE
aspirin and NSAIDs
what are the clinical signs and symptoms for CRC ?
usually asymptomatic until late stage
b symptoms - weigh loss , fever , night sweats
fatigue due t blood loss
severe diarrhea - in large villous adenomas in distal colrectum
palpable abdominal mss
symptoms can vary according to where the tumor is located what are the symptoms if located right side ?
cecum and ascending colon
melena - iron def anemia
diarrhea
cecum - dyspepsia and appendicitis
symptoms can vary according to where the tumor is located what are the symptoms if located left side
TRANSVERSE AND DESCEDING COLON
progressive constipation or change in bowel habits
blood streaked stools
colic like abdominal pain due to obstruction
symptoms can vary according to where the tumor is located what are the symptoms if located at rectum or sigmoid ?
Hematochezia- bright red stools rectal pain tenesmus flatulance involuntary stool loss
rectum - bladder symptoms
what are the metastatic signs and symptoms ?
if liver : abdominal distension , hepatomegaly , ascots
lung - dyspnea , cough , hemoptysisi , pleural effusion
what’s the diagnosis fo CRC ?
complete colonoscopy with biopsy - golden standard
if incomplete - double contrast barium enema
capsule endoscopy
staging
CT
endorectal ultrasound
