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Gastro + Gen Surg > Colorectal Cancer > Flashcards

Colorectal Cancer Flashcards

1
Q

What are the risk factors for colorectal cancer?

A 
FH
Familial adenomatous polyposis (FAP) 
Hereditary nonpolyposis colorectal cancer (HNPCC)/Lynch syndrome 
IDB
Age 
Diet high in red and processed meat 
Obesity 
Sedentary lifestyle 
Smoking
Alcohol
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2
Q

What is the underlying pathological of FAP? What would you expect to see on colonoscopy? How can you confirm FAP and what are the consequent interventions?

A

AD condition involving mutation in APC (adenomatous polyposis coli) TSG. APC normally controls the tumour potential of endothelium cells by regulation cell division and tissue interaction. Mutation leads to overgrowth of endothelial lining= produces polyps

FAP= >100 polyps

Genetic test + detailed family history

Prophylactic panproctolectomy

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3
Q

What is the pathophysiology of HNPCC/Lynch syndrome? Which part of the colon is preferentially affected?

A

AD condition where there is mutation in MMR genes. Unable to repair DNA and cellular damage due to MMR normally coordinating/producing proteins involved in repair. Leads to persistence of cancer associated mutations
Polyps (adenomas) don’t form in associate with HNPCC

Right colon

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4
Q

What other cancers is someone with HNPCC at an increased risk of?

A 
Endometrial 
Ovarian 
Renal 
Ureter
Small bowel 
Stomach 
Pancreas
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5
Q

How might someone with colorectal cancer present?

A

Change in bowel habits to more loose and frequent stools

Unexplained weight loss 
Rectal bleeding 
Unexplained abdo pain 
IDA= microcytic and low ferritin 
Abdo or rectal mass 
Obstructive symptoms if cancer large enough to block passage 
-vomiting 
-abdo pain 
-absolute constipation
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6
Q

If someone presents with IDA w/o any other explanation for the IDA, what is the recommendation?

A

2 week wait referral for GI malignancy and refer for colonoscopy and gastroscopy because microscopic bleeds associate with GI malignancy can lead to IDA w/o it being visible in stool samples

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7
Q

What is the faecal immunochemical test (FIT) and when is it used?

A

Looks for human Hb in stool (NOT blood)

Used in GP to assess for bowel cancer in patients who don’t meet 2 week wait criteria
Used as part of bowel cancer screening program (60-74)

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8
Q

What investigations are done in patient presenting with S+S of colorectal cancer?

A

FBC= check for anaemia

LFT= look for signs of liver mets

U+E= large tumour may be obstructing the ureters and causing a post-renal AKI

CEA tumour markers-> used to predict relapse

AXR= bowel obstruction

CXR= look for lung mets

USS= look for liver mets

Colonoscopy= visualisation of lesions and can taker biopsy

Sigmoidoscopy= rectum and sigmoid only i.e. when only sign is rectal bleeding (can miss cancer at other points in the colon)

CT colonography= when patients not fit for colonoscopy

Staging CT scan= CT TAP i.e. looking for metastasis

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9
Q

What is the criteria for the different TNM classifications?

A 
TX= unable to assess size 
T1= submucosa involvement 
T2= muscularis propria 
T3= suberosa + outer later of serosa 
T4= A= spread through serosa B= reaching other tissues and organs 
NX= unable to assess nodes 
N1= no nodal spread 
N2= spread to 1-3 nodes 
N3= spread to more than 3 nodes 
M0= no metastasis
M1= metastasis
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10
Q

What type of cancer is CRC most commonly?

A

Adenocarcinoma

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11
Q

What are colonic adenomas?

What are the 3 classifications?

A

Benign precusors to colorectal cancer characterised by dysplastic epithelium

Tubular
Villous
Tubovillous

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12
Q

How might someone with colonic adenomas present?

A

Normally asymptomatic

May notice blood in stool= due to larger polyps bleeding -> can present with anaemia

Hypokalaemia due to villous adenomas causing depleting syndrome

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13
Q

What are the stages of the adenoma-carcinoma sequence?

A

Normal colon cells transformed into adenomatous polyp due to genetic endogenous factors

Adenomatous polyp transformed to displastic polyp due to combination of endogenous and exogenous factors i.e. inflammation/oxidative stress/physical inactivity/smoking/drugs/alcohol/diet/obesity

Displastic polyp transforms to colon cancer due to increased oxidative stress and chronic inflammation leading to promotion of oncogenic phenotype

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14
Q

What are the most common sites for CRC?

A

Rectum = 35%

Sigmoid = 25%

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15
Q

What are the clinical features of right sided colon cancer?

Why is bowel obstruction less common on the R?

A

RIF mass

Alternating bowel habits

Peristant anaemia-> IDA due to bleeding from mucosa

Blood mixed in stool or not noticed

Signs of bowel obstruction
-less common due to right side having a wider lumen

Acute appendicitis
-due to R-sided tumour invading into appendix

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16
Q

What are the clinical features of left sided CRC?

A

PR bleeding

Alternating bowel habits

LIF mass

Bowel obstruction

17
Q

What are the clinical features of rectal cancer?

A

PR bleeding

Tenesmus
-due to rectum being sensitive to stretch and a growing tumour causing the rectum to stretch

Morning diarrhoea
-due to tumour producing mucus and this combining with morning mucus to give appearance of diarrhoea

Perforation

Haemorrhage

Fistula

18
Q

What is the macroscopic appearance of CRC on colonoscopy?

A

Exophytic cauliflower growth

Ulcerating lesion penetrating through bowel wall

Annular constricting growth

Tubualar

19
Q

How would you differentiate histologically between adenocarcinoma and polyps?

A

Adenocarcinoma:

  • disordered gland architecture
  • irregular branching shape

Polyps (dysplastic epithelium)

  • pseudostratified
  • hyperchromatic cells
  • elongated nuclei
20
Q

How is CRC graded?
What does this indicate about the tumour?
What does it mean if a tumour is “high grade” and “loe grade”?

A

Graded based on the differentiation of the cells

Indicates how aggressive the tumour is

High grade= cells do not resemble the normal cells
Low grade= cells look similar to normal cells

21
Q

What staging system is specific to CRC?

What do the stages mean?

A

Dukes (stages A-D)

A= Limited to mucosa

B1= extending into muscularis propria but not penetrating through it

B2= penetrating through muscularis propria, nodes not involved

C1= extending into muscularis propria but not penetrating through it

C2= penetrating through muscularis propria. Nodes involved

D= Distant metastatic spread

22
Q

What are the local sites of CRC spread?

A

Ovaries
Uterus
Bladder

23
Q

What are the most common sites for metastasis for CRC?

What signs/symptoms might someone present with that suggests their CRC might have metastasised?

A

Liver

Lung

Peritoneum

Jaundice
Deranged LFT
Ascites
Shortness of breath

24
Q

What pathological features affect prognosis?

A 
Tumour size
Number of tumours
Extent of necrosis
Grade of tumour 
Involvement of resected margins

Gastro + Gen Surg (45 decks)

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