The Case Of The Man Who Wanted To Know The Future Flashcards
cancer staging
a classification system that describes how far a cancer has spread
colorectal cancer stage 1
confined to mucosa
colorectal cancer stage 2
penetrates muscularis of colon wall
colorectal cancer stage 3
tumour penetrates serosa
colorectal cancer stage 4
tumour invades other structures, distant metastasis
TNM
T = size of T umor N = N ode involvement M = M etastases
how do you look for distant metastasis?
CT, occasionally PET
what imaging modalities can assist biopsy?
ultrasound or CT
types of new tumour therapies in interventional radiology
trans-arterial chemoembolisation
selective internal radiotherapy
particle embolisation
tumour ablation
radiofrequency ablation
An interventional radiologic technique in which tumors are removed from tissues by heating
limitation of RFA currently
only good for tumours about 2-3cm big, heating zone not wide
cryoablation
destroying tumours with liquid nitrogen
what cancer is US ablation promising for?
breast cancer
4 subdivisions of colorectal cancer
colon cancer
rectal cancer
oligo-metastatic
widespread metastatic
symptoms of colorectal cancer (4)
anaemia
rectal bleeding
change in bowel habit
tenesmus
tenesmus
The feeling that you need to pass stools, even though your bowels are already empty. It may involve straining, pain, and cramping.
Hallmarks of Cancer
Sustaining proliferative signaling Evading growth suppressors Activating invasion and metastasis Enabling replicative immortality Inducing angiogenesis Resisting cell death
cancer enabling characteristics
tumour promoting inflammation
genome instability
key 1st gene affected in colorectal cancer
APC gene - a tumour suppressor
how do polyps progress to cancer?
APC loss causes initial polyp
KRAS mutation causes bigger polyp
more mutations in p53 and Chr 18 then get cancer
KRAS
Oncogene associated with colorectal cancer
how does mismatch repair lead to cancer?
epigenetic loss of one of the mismatch repair genes, get multiple point mutations by accident, eventually switch off a tumour suppressor
how much colorectal cancer is hereditary?
how much colorectal cancer is hereditary?
3-5%
Familial Adenomatous Polyposis (FAP)
Autosomal dominant disorder characterized by 100s to 1000s of adenomatous colonic polyps, get inevitable subsequent mutations leading to colorectal cancer
Hereditary Nonpolyposis Colon Cancer/Lynch Syndrome
An autosomal dominant disorder associated with faulty mismatch repair gene so get multiple point mutations
which cancers are you at increased risk of if you have Lynch syndrome?
colorectal
endometrial
pancreatic
small bowel
treating FAP
prophylactic pan-colectomy by aged 40
treating HNPCC
regular screening colonoscopy and preventative aspirin 600mg
screening for bowel cancer
faecal immunochemical test offered to over 60s, if positive go for a colonoscopy
adjuvant chemotherapy
the use of chemotherapy after or in combination with another form of cancer treatment such as administering chemotherapy after surgery or with radiation therapy
How does colorectal cancer spread?
direct extension
via portal circulation to liver
via venous circulation to lung
common mutations in colorectal cancer
RAS
RAF
MEK
ERK
which is the key mutation in CRC which renders EGFR inhibitors useless?
RAS mutation
Sotorasib
a potential upcoming cancer drug for CRC with KRAS mutations
prevalence of KRAS mutation in CRC
about 40%
Cetuximab
EGFR inhibitor used in colorectal cancer
how can you discover patients at risk of metastatic disease?
do blood tests and PCR for circulating tumour cells or DNA, these people can then have adjuvant chemo as well as surgical resection
Immune checkpoint inhibitors
Take the “brakes” off the immune system, which helps it recognize and attack cancer cells, potential use in CRC that are mismatch repair gene deficient
Immune checkpoint inhibitors
lots of mutations makes cells more ‘foreign’ so more easily targeted by native immune system
