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Cancer Care > Colorectal > Flashcards

Colorectal Flashcards

1
Q

How do most colorectal cancers arise and what is the most common type?

A

From polyps to form adenocarcinomas

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2
Q

What are the layers of the bowel wall, from lumen outwards?

A

Mucosa - contains connective tissue lamina propria and muscularis mucosa.

Submucosa - connective tissue, glands, vessels, lymph nodes, nerves

Muscularis propria
Subserosa
Serosa

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3
Q

What are risk factors for colorectal cancer?

A 
Family history
Hereditary syndromes
Inflammatory bowel disease
Ethnicity
Radiotherapy
Obesity
Diabetes mellitus
Smoking
Western diet - low fibre, high fat, red/processed meat

Increased exercise is protective

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4
Q

What hereditary syndromes increase the risk of CRC?

A

Hereditary nonpolyposis colorectal cancer/Lynch syndrome - autosomal dominant mutation

FAP - familial adenomatous polyposis - autosomal dominant mutation of APC (tumour suppressor gene)
Development of polyps that could undergo malignant change

Require annual colonoscopy

MYH associated polyposis
Serrated polyposis
Juvenile polyposis
Peutz-Jeghers syndrome

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5
Q

What is the adenoma-carcinoma sequence?

A

Mutations accumulate
Normal epithelium develops adenomas which become progressively more dysplastic = carcinoma

APC mutation leads to hyper proliferative epithelium, then KRAS mutation of proto-oncogene - oncogene.
The mutation of p53 and SMAD4 leads to development of carcinoma

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6
Q

Where does CRC most commonly occur?

A

Rectum and sigmoid colon

Most commonly affect the left side of the colon

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7
Q

Where do CRCs commonly spread?

A

Liver most commonly

Rectal cancers commonly associated with lung mets due to haematogenous spread via inferior rectal vein and IVC

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8
Q

What are the clinical features of CRC?

A 
Change in bowel habit
Weight loss, malaise
Tenesmus, PR bleeding
Abdominal pain
Pallor
Abnormal PR exam, mass
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9
Q

How does the presentation of right sided to left sided colon cancer differ?

A

RS: weight loss, weakness, rarely obstruction, iron deficiency anaemia, late

LS: constipation, abdo pain, alternating bowels, rectal bleeding, bright red PR bleeding, large bowel obstruction

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10
Q

How does a rectal cancer present?

A

Obstruction, tenesmus, bleeding
Bright red PR bleeding
Palpable mass on DRE

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11
Q

How can mets present with liver involvement?

A

Hepatomegaly
Jaundice
Abdo pain
Lymphadenopathy

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12
Q

What appearance can left sided lesions present as?

A

Have a tendency to grow circumferentially, creating an apple core appearance
So leads to narrowing of the lumen - obstruction

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13
Q

What screening is available?

A

FIT test - Faecal Immunochemical test for presence of blood in the stool
56-74 home test kit every 2 years

Those with abnormal results will be invited for colonoscopy

One-off flexible sigmoidoscopy paused since COVID19 - aged 55

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14
Q

Who should be referred for two week wait?

A

Most can be sent straight to test for colonoscopy unless contraindication/complication

Aged 40 + with unexplained weight loss and abdo pain
Aged 50 + and unexplained rectal bleeding
Aged 60 + with iron deficiency anaemia, change in bowel habits
Test shows occult blood
Consider patients with rectal or abdominal mass

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15
Q

What are the investigations for suspected CRC?

A

Colonoscopy is the gold standard investigation

CT pneumocolon - but cannot take biopsy or remove polyps

CT abdomen pelvis with or without contrast

Bloods - FBC, iron, transferrin, TIBC, renal function, LFT, clotting

Tumour markers - CEA

MRI liver, rectum
Endoanal USS
PET/CT for staging

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16
Q

When should neoadjuvant therapy be offered?

A

Rectal cancer T1-T2, N1-N2, M0

Colonic cancer with cT4 consider use of chemo

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17
Q

What are some examples of adjuvant therapy?

A

FOLFOX - Folinic acid, Fluorouracil, Oxaliplatin

CAPOX - Capecitabine and Oxaliplatin

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18
Q

What is the Duke staging?

A

A - tumour confined to mucosa
B - growth into muscularis propria +- serosa
C - spread to lymph nodes
D - distant mets; liver, lung, bones

19
Q

What signs would suggest advanced colorectal cancer?

A

Hepatomegaly

Jaundice

20
Q

When is a right hemicolectomy performed? What is done during the procedure?

A

Any ascending colon tumours

Part or all of ascending colon and cecum removed. Colon anastomosed to small intestine (ileo-colic)

21
Q

When is a left hemicolectomy performed? What is done during the procedure?

A

Any descending colon tumours

Part or all of descending colon removed. Transverse colon anastomosed to rectum (colo-colic)

22
Q

When is a sigmoid colectomy performed? What is done during the procedure?

A

Tumours affecting the sigmoid colon

Part/all of sigmoid colon removed. Descending colon connected to rectum (colo-rectal)

23
Q

When is an anterior resection performed? What is done during the procedure?

A

High anterior resection: sigmoid tumours
Anterior resection: rectal tumours

sigmoid colon and portion of rectum removed. Colorectal anastomosis formed
+TME (removal of mesorectal fat and lymph)

24
Q

When is an abdo-perineal resection performed? What is done during the procedure?

A

Lower rectal tumours and any tumour involving the sphincter

removes the anus, rectum, and sigmoid colon. No anastomosis

25
Q

Where does a HNPCC colon cancer normally affect?

What other cancers is HNPCC associated with?

A

Proximal colon

Endometrial

26
Q

What are some complications of colorectal cancer surgical management?

A

Anastomotic leak, adhesions, hernia

Stoma complications:
- parastomal hernia, ischaemia/necrosis, obstruction, skin irritation, prolapse, retraction leading to a poor bag seal

27
Q

What is Hartmanns’ procedure?

A

Resection of sigmoid colon, closure of the anorectal stump and formation of end colostomy

28
Q

What are the advantages and disadvantages of parenteral nutrition?

A

little patient effort

sepsis
catheter obstruction
thrombosis
refeeding syndrome

29
Q

What are the advantages and disadvantages of enteral nutrition?

A

low cost
maintains gut
few infection risks

aspiration risk
tube displacement
gastric distention
risk of malnutrition

30
Q

What are the most common tumours that cause bony mets?

A

Prostate, breast, lung

31
Q

Where are the most common sites for bony mets?

A

Spine, pelvis, ribs, skull, long bones

32
Q

What are hamartomas?

A

Hamartomatous polyps
Non cancerous tumours made of overgrowth of normal cells
Usually asymptomatic
Not associated with malignant transformation or increased risk of colorectal cancer

33
Q

What are some of the side effects of bowel resection?

A 
Pain, bleeding
Thrombosis
Paralytic ileus
Abdominal adhesions
Anastomotic leak
Infection
Sexual problems - erectile dysfunction, retrograde ejaculation, dry orgasm
Bladder problems - urinary incontinence, urgency, frequency
34
Q

What are some of the side effects of chemo?

A 
Bone marrow suppression
Diarrhoea
Skin changes - rash, photosensitivity
Hair loss
Sore mouth and throat - stomatitis, oral mucositis
Nausea and vomiting
Loss of appetite
Pain at the injection site
Peripheral neuropathy
Liver damage
Allergic reactions
35
Q

What are some agents that can be used in targeted therapy?

A

Cetuximab
Panitumumab
Bevacizumab

36
Q

What are treatment options to those with early rectal cancer?

A

Transanal excisions
Endoscopic submucosal dissection
Total mesorectal excision

Total mesorectal excision with anterior or AP resection in more advanced rectal cancers

37
Q

What should be performed in a follow up?

A

Physical examination
Attention to Virchow’s node left supraclavicular node
CEA for elevation
Colonoscopy within 12 months of completing primary treatment, then every 3 years, then every 5 years
Those with rectal cancer undergo flexible sigmoidoscopy
CT chest and abdomen, CXR rectal cancers check for mets

38
Q

What are some specific side effects in chemotherapy?

A

5FU/capcitebine - hand and foot skin breakdown
Oxaliplatin - peripheral neuropathy
HTN and GI bleeds - Bevacizumab
Skin rashes - cetuximab

39
Q

What are the main signs and symptoms of large bowel obstruction?

A 
Absolute constipation
Vomiting (late stage)
Abdominal distention
Loud normal bowel sounds
Non tender abdomen
Empty rectum
40
Q

How is large bowel obstruction managed?

A

Conservatively - drip and suck

fluid resuscitation and intestinal decompression or stenting endoscopy

41
Q

How would a competent ileo-caecal valve affect large bowel obstruction?

A

Fluids and materials can pass in but not out meaning the large bowel distends rapidly and the caecum will rupture causing peritonitis

If incompetent, small bowel will also distend so perforation isnt as big a risk

42
Q

How does small bowel obstruction present?

A 
Colicky umbilical pain
Vomiting - pain relief
Abdominal distention
Tinkling bowel sounds
Palpable loops of bowel
43
Q

How is small bowel obstruction managed?

A

Drip and suck - fluid resus and tube for decompression

Watch and wait as may need laparotomy

44
Q

What is a complication of small bowel obstruction?

A

Strangulated obstruction when blood supply become impaired –> ischaemia and gangrene within 6hrs of onset

Cancer Care (15 decks)

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