Colorectal Cancer Flashcards
colorectal cancer becomes much more common after what age?
65
risk factors for bowel cancer?
older age low fibre diet diet high in fat, sugar, alcohol, red meat, processed meat obesity smoking lack of exercise long term constipation
how can bowel cancer be genetic?
inheritance of APC gene mutation causing familial adenomatous polyposis (FAP) which results in a 100% lifetime risk of developing bowel cancer
can also have P53 gene mutation
what condition can predispose to bowel cancer?
long standing UC
higher risk the longer you have it so more chance of developing cancer if diagnosed as a child
how can bowel cancer spread?
direct spread
lymphatic spread
blood borne spread to liver and lung
transcoelomic spread (rare)
in which 3 ways can bowel cancer present?
screening
urgent via surgical outpatients or endoscopy (most common)
emergency presentation
scotland screening programme?
stool sample every 2 years in 50-72 year olds
if positive a colonoscopy is offered
how might patients present urgently via surgical outpatients or endoscopy?
urgent referral from GP with red flag symptoms
referral then vetted by gastroenterologist to decide if patient needs to go to surgical outpatients or straight to endoscopy
how might bowel cancer present as an emergency?
obstruction
rectal bleeding
palpable mass
perforation etc
bowel cancer red flags?
bleeding
change in bowel habit
weight loss
signs and symptoms of right sided bowel cancer?
unexplained iron deficiency anaemia (cancer bleeds) persistent tiredness (due to anaemia?) persistent and unexplained change in bowel habit (>6 weeks) unexplained weight loss abdominal pain (colicky) lump in abdomen
signs and symptoms of left sided bowel cancer?
rectal bleeding
feeling of incomplete emptying
worsening constipation
important questions to ask if suspicious of bowel cancer?
any recent change in bowel habit? any bleeding? and what colour? mixed with stool or seperate? any weight loss? any abdo pain? and abdo swelling? any family history? any previous surgery?
how is bowel cancer investigated?
colonoscopy is best (visualises whole colon, can do biopsy and polyp removal at same time)
sigmoidoscopy visualises less, done if less red flags?
CT colonography done if cant toelrate colonoscopy or for completeion if entire colon cant be seen on colonoscopy due to obstruction
features of cancer on colonoscopy?
rolled edges
central necrosis
just looks bad basically
where do you take a biopsy from?
rolled edge of cancer
not from middle as this is usually necrotic
how is CT colonography performed?
required bowel prep and faecal tagging with picolax + omnipaque and gastrografin
bowel also inflated with CO2
buscopan given IV to relax bowel
which type of polyp is most dangerous?
sessile (flat to bowel wall) as the cells are closer to underlying structure so if it becomes cancerous it will spread quicker
how does a poly progress to cancer?
normal epithelium > hyperproliferation of epithelium > small adenoma > large adenoma > colon carcinoma
next steps after bowel cancer is diagnosed?
histopathology confirmation
cancer staging (CT chest/abdo/pelvis, MRI for rectal cancers)
surgery or palliative treatment
follow up
how can cancer be seen on CT?
irregularly narrowed lumen with a sharp demercation between normal and abnormal bowel (not always visible as bowel might be contracted in peristalsis or spasm)
why is MRI used in rectal cancer?
shows all the lymph nodes in the mesorectal fascia (fatty tissue surrounding the rectum) so shows spread of rectal cancer
(lots of lymph nodes in mesorectal fascia so need to remove it all)
blood supply to the colon?
superior mesenteric supplies ascending and transverse colon via ileal artery, ileocolic artery, right colic artery (only present in 20% of people) and middle colic artery
inferior mesenteric supplies descending colon, sigmoid colon and rectum via left colic artery, marginal artery, sigmoid artery and haemorrhoidal artery
what is the marginal artery of drummond?
continuous artery along the inner surface of the colon formed of the terminal branches of superior and inferior mesenteric
describe right hemicolectomy?
ascending colon removed and ileum joined to transverse colon forming an ileocolic anastomosis
describe an extended right hemicolectomy?
ascending and part of transverse colon removed
ileocolic anastomosis formed again
describe a transverse colectomy?
only transverse colon removed so hepatic and splenic flexures joined together
done in elderly patients with shorter life expectancy as higher complication/recurrence rate??
describe a sigmoid colectomy?
sigmoid colon removed and descending colon attached to rectum
hartmanns procedure is actually just a signoid colectomy but with a stoma rather than an anastamosis
what is an anterior resection?
part of rectum with cancer removed and sigmoid colon reattached to lower part of rectum
what is an APR (abdominoperineal resection)?
removal of whole rectum and anus etc
entire back passage is cored out and external opening is sewed up so theres no anal opening
if a patient has a colostomy, what procedure have they had?
either a hartmanns or APR
differentiate by asking if they still have a bum hole
how is colorectal cancer staged?
TNM
still see dukes sometimes but basically not used anymore
what is done after operation?
chemotherapy/radiotherapy depending on staging
5 year? follow up with CT, CEA, colonoscopy
types of advanced colorectal cancer management?
cancer resection + chemo
cancer + liver + lung resection
HIPEC (hyperemic intraperitoneal chemotherapy) for mesothelioma, pseudomyxoma peritonei and peritoneal metastasis
palliative treatment for colorectal cancer?
stenting
radio/chemotherapy
defuncitoning (creation of a stoma before cancer to allow patient to eat and drink without obstruction)
bypass
