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Year 3 Surgery > 6 - Lower GI Malignancy > Flashcards

6 - Lower GI Malignancy Flashcards

1
Q

What are the RF for colorectal cancer?

A
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2
Q

What are the histological subtypes of polyps?

A

Adenomatous polymps (adenomas)
Hyperplastic polyps
Sessile serrated polyps
Non-neoplastic polyps (inflammatory)

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3
Q

What is the stepwise progression from normal bowel mucosa to bowel cancer known as?

A

Adenoma-carcinoma sequence

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4
Q

What is the peak incidence age for polyps and for BC?

A

Polyps = 60
BC = 71

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5
Q

How can polyps be managed?

A

They can be endoscopically removed during a colonoscopy or they can be surgically resected if too large.

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6
Q

Once a polyp has been removed - what determines whether further treatment is needed?

A

Depth of invasion

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7
Q

Which two scales predict lymphatic involvement for polyps?

A

Haggitt level (pedunculate)
Kikuchi level (sessile)

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8
Q

What age does screening for CRC take place? What is the process of screening?

A

From age 60-74 - although currently transitioning to 50.

Screening process = qFIT

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9
Q

How to most cases of CRC present?

A

1/3 from screening
Some incidental on screening for polyps
Most are from symptomatic Ps
25% are as an emergency presentation - e.g. BO

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10
Q

What symptoms could be suggestive of CRC?

A

A combination of sx are more likely to be indicative of CRC
- e.g. IDA and CIBH - 10% PPV

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11
Q

Which is the strongest single predictor of underlying bowel cancer?

A

Iron deficiency anaemia - has a PPV of 5%

Significant anaemia is more concerning - Hb<90 has a 10-15% PPV for CRC

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12
Q

What is the commonest cause of iron deficiency anaemia?

A

Coeliac disease

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13
Q

What is the diagnostic criteria for iron deficiency anaemia?

A

Hb <130/L M and <120/L F
Hypochromic / microcytic anaemia (low MCH / MCV)
Low ferritin levels
Transferrin sat low

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14
Q

When should you be more concerned about a CIBH?

A

When there are nocturnal Sx as these are not present usually in IBS. IBS usually biggest cause of CIBH.

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15
Q

How can CRC present as an emergency?

A

Acute PR bleeding
Bowel obstruction
Bowel perforation
Fistula formation
Infection/abscess

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16
Q

What does qFIT detect?

A

Presence of human globin in stool

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17
Q

What diagnostic imaging can be uses for CRC?

A

Colonoscopy - gold standard
Flexible sigmoidoscopy
Virtual colonoscopy (can’t see small <6mm polyps)

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18
Q

Which tumour marker is linked to CRC?

A

CEA

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19
Q

How is CRC staged?

A

Colonoscopy = biopsy - can then identify tumour immunohistochemically

CT Abdo, Chest & Pelvis

MRI - used for rectal cancer as colon to mobile for MRI (therefore CT needed)

PET - more often used for other types of cancer

Tumor marker - CEA

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20
Q

What Tx is available for CRC?

A

Radiotherapy (rectum only - again colon too mobile)
Surgery
Chemo
Immunotherapy

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21
Q

What temporary procedure can be used in emergency presentation as a bridge to surgery in CRC?

A

Insertion of a stent into the colon - can also be used as a palliative measure.

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22
Q

What are predictors of poor outcomes in CRC?

A
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23
Q

What does Lynch syndrome cause?

A

Genetic abnormalities to the mismatch repair genes - means that mutations in oncogenes or tumour suppressor genes are easier to acquire.

Different abnormalities to different mismatch repair genes give you different risk of different cancers - MLH1 and MSH2 are the biggest risks for endometrial and CRC.

Also inc risk of endometrial, renal cell, breast, upper GI and prostate cancers depending on phenotype.

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24
Q

Which criteria is used to identify families at risk of Lynch?

A

The Amsterdam criteria

25
Q

How is Lynch syndrome managed?

A

Surveillance of colon every 2 years from 25 or 35 years depending on type of MMR gene affected.

Fs - should have hysterectomy and bilateral salpingo-oopherectomy from age 40.

Aspirin daily reduces risk of CRC by 50%.

Counselling

26
Q

What is the commonest type of CRC?

A

Adenocarcinoma

27
Q

What type of cancer involves the anus?

A

Anal squamous epithelial cancer

28
Q

Why are rates of anal cancer expected to fall in the future?

A

Anal cancer is almost 100% caused by HPV 16 & 18 - is hoped that the HPV vaccination will almost remove the chances of getting anal cancer.

29
Q

How do patients with anal cancer present?

A

PR bleeding
Anal mass
Anal pain

30
Q

What is the pre-malignant phase of anal cancer known as?

A

Anal intra-epithelial neoplasia (AIN)

31
Q

How is AIN graded? What percentage of these will progress to anal cancer?

A

AIN headed I to III

9-13% of Grade III will progress to anal cancer if untreated

20% of AIN III will regress to AIN I

32
Q

How is AIN managed?

A

Confirm diagnosis = biopsy

Tx - can remove new anal / perianal lesions with surgery / laser / topical.

SCC is radiosensitive but relatively chemo resistant - primary treatment is radiotherapy.

Persistent or recurrent disease is treated with radical salvage surgery = extra-levator abdominoperineal excision (ELAPE)

33
Q

What is the prognosis of anal cancer?

A

80% 5 year survival for non-metastatic disease

34
Q

How common is CRC in the UK?

A

3rd most common cancer for M and F

35
Q

Why is CRC more common in the West?

A

To do with dietary habits

36
Q

What does survival depend upon for CRC?

A

Stage at presentation

37
Q

What are the RF for bowel cancer?

A
38
Q

What are the RF for squamous cell carcinoma of the anus or rectum?

A

Anal sex
Multiple sex partners
HPV
Immunosuppression - HIV / LT immunosuppressive drugs

39
Q

What are the histological classifications of bowel cancer?

A

Adenocarcinoma - 90%
Squamous cell
Adenosquamous type
Neuroendocrine
Spindle cell

40
Q

Where does adenocarcinoma arise from?

A

Glandular tissue

41
Q

What is adenosquamous carcinoma?

A

Uncommon malignant neoplasm of the skin characterized by mixed squamous and glandular differentiation and aggressive clinical behavior, such as extensive local invasion, recurrence, and rare metastasis.

42
Q

What is spindle cell sarcoma?

A

A rare malignant (cancerous) tumour which can develop in the bone or soft tissue. It can arise in any part of the body but is most common in the limbs (arms and legs).

43
Q

In which part of the bowel is squamous cell carcinoma most commonly found?

A

Anus, Rectum and rectosigmoid junction

44
Q

In which part of the bowel is adenocarcinoma most commonly found?

A

Can be found anywhere but large majority are found in the sigmoid colon and the caecum

45
Q

Mutations of which tumour suppressor genes can lead to evasion of growth suppression of cells?

A

TP53
RB

46
Q

Which type of pathways are responsible for proliferative signalling in cells?

How do cancer cells alter these?

A

Tyrosine kinase pathways
Cancer cells deregulate these pathways - allowing them to sustain proliferation without regulation.

47
Q

Which cell adhesion molecule is down regulated by cancer cells to allow cells to invade and metastasise?

A

E-Cadherin

48
Q

Which growth factor is linked to induction of angiogenesis by cancer cells?

A

VEGF

49
Q

Down regulation of what in cells enables cancer cells to resist death?

A

Loss of P53 and dowregulation of BCI2 and RIP kinases

50
Q

How can cancer cells avoid immune destruction?

A

They can lower their MHC1 expression to avoid detection

They cal also destroy apoptotic signalling pathway molecules - such as Cascade 8, VCL2 and IAP.

51
Q

Which is the most common hereditary bowel cancer?
What risk of colon cancer does this give a patient?
What is the mean age of diagnosis?

A

HNPCC - Lynch Syndrome - is AD
80% lifetime risk of colon cancer
Mean age of diagnosis = 44-61 years

52
Q

What type of cells are seen in cancer caused by Lynch Syndrome?

A

Mucinous adenocarcinomas - poorly differentiated

53
Q

How does Lynch syndrome cause colon cancer?

A

It causes a germline mutation in one of the mismatch repair genes (MLH1, MSH2, MSH6, PMS2). This increases the risk of cancer as nucleotide base mistakes are not corrected during DNA replication.

54
Q

How does Familial Adenomatosis Polyposis cause colon cancer?

A

Is an AD condition

It causes a loss or mutation of the APC gene at Chr 5. When this suffers an inevitable second hit => multiple polyps (hundreds) = inevitable progression to cancer.

55
Q

What is the prognosis for Ps with FAP?

A

Not great - if untreated majority will die in their 4th decade

56
Q

What is the treatment for FAP?

A

Total or partial colectomy +/- proctecomy (removal of rectum)

Prophylactic NSAID use

57
Q

Why can colon cancers metastasise to the liver?

A

Due to the portal circulation - blood from the gut is drained directly to the liver. Just because you have liver mets doesn’t mean you will have mets elsewhere.

58
Q
A

Year 3 Surgery (15 decks)

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