Cancer imaging and staging

Question 1

STAGING OF TUMOURS

i) give three reasons for staging a tumour
ii) what is local staging? what is stage I and what is stage IV?
iii) which criteria is used for local staging of bowel cancer? what does a stage III bowel cancer mean?
iv) which imaging modality is best for staging pelvic cancers
v) name two structures a rectal cancer may invade if it is stage IV

Answer 1

i) to determine treatment options (surgery, chemo, RT)
- to predict prognosis
- enable patient discussions

ii) process of determining the extent at which a cancer has developed by spreading
- stage I = isolated cancer
- stage IV = cancer that has spread to the limit of what the assesment measures

iii) Dukes criteria
- stage III = any tumour stage with nodal mets but no distant mets > invades the serosa

iv) MRI
v) peritoneum and adjacent organs

Question 2

TNM CLASSIFICATION

i) which type of tumours does this not apply to?
ii) explain T1-4 for colorectal cancer
iii) which type of tumours can be have their nodes further subclassified into N1 and N2?

Answer 2

i) lymphoma and haematological cancer

ii) T0 - no evidence of primary
Tis - carcinoma in situ
T1 - tumour invades submucosa
T2 - tumour invades muscularis propria
T3 - tumour invades through muscularis into the subserosa or into non peritoneal perirectal tissue without reaching mesorectal fascia or adj organs
T4 - tumour invades other organs or perforates visceral peritoneum

iii) rectal tumours

Question 3

PET/CT

i) which scan is the standard to establish whether there are distant mets? which is more specialist?
ii) give two situations when a PET might be used
iii) how does FDG imaging work? why do tumours show up?

Answer 3

i) CT is routine and PET is more specialised
ii) if there is borderline LN involvement, if there are lung nodules
iii) cancer cells are highly metabolically active therefore take up glucose > inject FDG its taken up by tumour cells > decay can be detected as it emits a positron

Question 4

TUMOUR BIOPSY

i) name three reasons to biopsy tumours
ii) name three important things to check before a patient has an IR guided biopsy?
iii) what are ideal INR and plat values to proceed?
iv) what anaesthesia will most people have?
v) how long will a patient likely be kept in after an US guided biopsy? what type of anaes is used?

Answer 4

i) determine the primary, determine histology and IHC, assess most appropriate treatment
ii) consent, are they NBM, abx prophylaxis, coagulopathy
iii) INR <1.5 and plats >50-80,000
iv) general

v) admit patient for 4hrs after
- use local anaes

Question 5

NEW TUMOUR THERAPIES

i) how does tumour embolisation work?
ii) what is TACE? give two cancers it may be used in? what does it consist of?
iii) what is SIRT?
iv) what is particle embolisation? is it inferior to TACE?

Answer 5

i) blocks artery that feeds the tumour > cell death

ii) TACE = trans arterial chemoembolisation
- put a catheter into the tumour and feed chemo through it
- used in primary hepatocellular carcinoma and isolated colorectal cancer
- use DOX linked to lipiodol (poppy seed extract taken up by liver tumours)

iii) SIRT = selective internal radiotherapy
- feed radioactive beads through a catheter > tumour for local RT effects

iv) particle embolisation > make the tumour ischaemic - not that much difference between that and targeted chemo