LGI Flashcards
A tumour is CK20 positive- this suggests which primary?
Adenocarcinoma of large bowel origin
How do you treat early and late onset irinotecan diarrhoea?
Early (24 hrs) high dose loperamide
Taking which drugs reduces risk of rectal cancer?
NSAIDs
What is the most common molecular abnormality in rectal cancer?
Chromosomal instability
MSI is rare
What is the frequency of BRAF mutations like in rectal cancer?
Low- unlike colon cancer
Indications post op DXT in a pt who has upfront surgery for rectal cancer?
Involved CRM
Indications post op chemo in a pt who has upfront surgery for rectal cancer?
Positive nodes
Tumour perforation
How long should oxali be given over to prevent pharyngolaryngeal dysethesia from recurring?
6 hours
The highest lymph node in the chain closest to the surgical tie is involved. What is it called and what Duke’s stage does it make it?
The high tie node
DUKE’s C2
Most common gene mutation in Lynch syndrome?
MSH2
Others MLH1 and MSH6
In what percent of anal SCC is HPV16 and 18 found?
90%
Is there screening for anal cancer in the UK?
Not currently
What is Gardasil?
Quatravalent vaccine against HPV 6, 11, 16 and 18
Protects against genital warts and cancer of the anus vagina and vulva
Boys not currently vaccinated
What percent of AIN 3 will progress to invasive anal cancer?
5%
What is the dentate line?
Line where below it the epithelium is squamous (it’s near the internal anal sphincter)
What percent of palpable inguinal nodes in anal cancer work up turn out to be malignant?
Only 50%- need FNA to confirm
Is PET useful for anal cancer staging?
Yes to pick up distant mets and is high sensitivity for nodes
How is the T stage in anal cancer worked out?
Size related T1 up to 2cm T2 up to 5cm T3 more than 5cm T4 any size invading adjacent organ (subcut tissue or sphincter doesn't count)
What percent of anal cancer is node positive at presentation? What does this mean for survival?
40% node positive
5 year survival 45%
Tell me about nodal staging anal cancer?
It's based on LOCATION of nodes N0 none N1 peri rectal N2 unilateral internal iliac or inguinal N3 bilat inguinal
What is the management of anal cancer?
Majority of patients definitive chemoradiotherapy
Only a v few T1 are suitable for excision biopsy (IE less than 2cm) - if leaves residual disease then give them chemoRT
What is the regimen of chemo RT for anal SCC?
DXT 50.4 Gy in 28# to primary and nodes
Chemo 5FU pumps (or cap) in two four day blocks
Mitomycin C bolus day 1 only
What is the complete response rate for definitive CRT for anal SCC?
80% (impressive!)
How long does it take for a tumour to regress completely after CRT for anal SCC?
6 months- don’t over biopsy
If patient fails then for salvage surgery- AP resection with stoma
What are the side effects of Mitomycin C?
Myelosupression- check weekly FBC
Dermatitis
Pulmonary fibrosis
Haemolytic uraemic syndrome
What changes have to be made if a patient with HIV has treatment for anal SCC with chemo RT?
None if CD4>400
If CD4
What is first line chemo for metastatic anal cancer?
Cis 5FU
Should you resect oligo met anal SCC?
No evidence for it but there are some case reports of successful liver met resections
Are polyps a big deal?
Well ALL colorectal cancer originally arises within precursor polyps so you could say so
What kind of polyp is the most risky in terms of CRC?
Pedunculated
What is the 10 year risk of a > 1cm polyp progressing to cancer?
15%
Name the three main molecular patterns of CRC?
(1) Chromosome unstable (80%) lots of chromosomal stuff
(2) DNA mismatch repair (15%) 1000’s of point mutations, small del, ins
(3) “serrated” CpG island hypermethylation. BRAF Mutant. RIGHT Sided.
RR of CRC if longstanding UC?
X10
% CRC familial
5%
Two main types familial CRC
FAP (APC gene)
HNPCC (Lynch syndrome) DNA mismatch repair (MSH2 most common)
Which familial CRC syndrome get tumours youngest?
FAP - have to start annual colonoscopy age 10!
In HNPCC start colonoscopy age 30
Management of risk in APC?
100% risk of CRC by age 40 so it’s intensive
Annual colonoscopy from age 10
OGD age 25
NSAIDS
Prophylactic colectomy and monitor rectal stump
What kind of gene is APC?
Gatekeeper TSG- controls wnt signalling pathway
Common mutations in CRC (4)
APC
KRAS
P53
PIK3CA
Two prognostic molecular biology factors in CRC:
Poorer prognosis 18q alleli can loss
MSI/MMR may identify patients at lower risk of recurrence
Describe the UK bowel screening program
Part 1 Age 60-74 faecal occult blood every 2 years reduces CRC mortality by 15%
In in 10 of those with positive FOBT will turn out to have cancer
Part 2 one off flexi sig age 55 NNTS 300 to pick up one CRC (ESMO don’t recommend a one off sigi)
Adverse signs in a colorectal polyp - unfavourable histology meaning operative resection needed
Invasion into stalk Grade 3 LVI Involved margin Invades sub mucosa
What structure do malignant cells have to cross in the bowel wall for them no longer to be in situ but become invasive?
Lamina propria
What is the significance of an elevated pre op CEA?
CEA>5 worse prognosis
Should normalise by 1 month post operative
How many nodes should be examined in CRC surgery?
At least 12
What is Dukes C1 disease in CRC?
Node positive but the highest node IE nearest surgical tie is negative
Who gets adjuvant treatment in CRC?
YES Node positive (stage 3 or dukes C) PLUS High risk Dukes B (t3 or t4) plus high risk features like Less than 12 LN sampled Poorly diff LVI Perf/obstr
What is the evidence for not giving oxaliplatin to patients over age 70?
MOSAIC trial sub analysis >70 did not benefit from adding oxaliplatin
What proximal and distal margins are needed with surgery for CRC?
5cm
Where is the cut off between rectal cancer and colon cancer?
15 cm from the anal margin
What is T2 and T3 rectal cancer?
T2 is in the muscularis propria
T3 is in the subserosal/ perirectal tissue
If rectal cancer has reached the serosal surface what stage is that?
T4a invasion of the visceral peritoneum
What is the impact on prognosis in CRC if a patient has BRAF mutation?
Adverse prognostic indicator
No consistent data on impact of EGFR treatment
Describe TNM anal scc
T1 up to 2cm
T2 up to 5cm
T3 more than 5cm
T4 any size invades adj organ
N1 perirectal
N2 unilat int iliac or unilat inguinal
N3 bilat inguinal
Indications for post Op RT in rectal cancer
And indications for post op chemo
Involved CRM
Tumour perf
Chemo:
Positive nodes
Tumour perforation
A rectal tumour extends 1mm from rectal wall what T stage is that?
T3a
Age a first degree relative has to be diagnosed with bowel cancer to make you at increased risk?
Below age 50
