Colorectal Cancer Flashcards
what is the screening test for colon cancer
qFIT
how does the qFIT test work
it detects hidden/occult blood in stool by using antibodies that test specifically for haemoglobin
a positive qFIT triggers a
urgent colonoscopy
describe the appearance of a polyp
on a stalk
projects into lumen
smooth surface
well defined
no obvious ulceration or haemorrhage
why might colon abnormality be recognised by someone started on aspirin
the aspiring thins their blood
more likely to bleed
so might bleed from colon when wouldn’t have otherwise
what are the cytological features of malignancy
high nucleus:cytoplasm ratio
hyperchromasia - darker nuclei in histology
pleomorphism
feature of an adenocarcinoma that makes it different to adenoma
it has invaded the base of the polyp and has less defined borders
common sites of metastasis in colon cancer
liver and lungs
what should be done after an adenocarcinoma is found on biopsy
CT scan or MRI to stage it
MDT meeting to determine next steps
consider surgery
what type of polyp has the most potential to progress to an adenocarcinoma
adenoma
what type of polyps don’t have malignant potential
hyperplastic
(except serrated polyp)
what type of polyp is very flat
serrated polyp
how are oncogenes expressed in tumour cells
either mutated to escape surveillance of body
or at high levels
is p53 a tumour suppressor gene or oncogene
tumour suppressor gene
what is the APC gene and what is it’s role in cancer
it encodes for the APC protein which is a tumour suppressor
APC protein regulates other things which are involved in cell adhesion
deletion of the APC gene predisposes to cancer
how long does it take to progress from a late adenoma to cancer
2-10 years
red flags for colon cancer
rectal bleeding
frequent nocturnal symptoms
weight loss
persistent diarrhoea
anaemia
thrombocytosis
new onset over 50
family history
PMHx IBD
is weight loss an early or late stage symptom
late stage
differential diagnosis for colon cancer
IBD
colon polyps
haemorrhoids
what group are more likely to have IBD than colon cancer
younger people
what is cancer grade
indication of invasiveness
based on how the patterns of cancer cells look under the microscope
degree of abnormality
what is cancer staging
describes how far the cancer has spread
what does TNM stand for
tumour - how far the primary tumour has grown into the wall of the organ and nearby organs
nodes - how many nearby lymph nodes the cancer has spread to
metastasis
alternative staging process to TNM
Duke’s
risk factors for colon cancer
high red meat and processed intake
cooking meats at very high temperatures (frying, grilling)
low fibre diet
age
male
smoking
alcohol excess
obesity
physical inactivity
history of IBD
family history of colorectal polyps or cancer
most common sites of colorectal cancer
sigmoid colon and rectum - 50%
caecum and ascending colon - 20-30%
who is screened for colon cancer
over 50s
is removal of adenomas curative
yes
