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Cancer Care > Colorectal > Flashcards

Colorectal Flashcards

1
Q

how common is colorectal cancer?

A

4th most common cancer in UK - 40,000 new cases a year
2nd highest mortality of any cancer

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2
Q

where does colorectal cancer originate from and what is the most common type?

A

epithelial cells lining the colon or rectum and is most commonly an adenocarcinoma

(rare lymphoma, carcinoid and sarcoma)

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3
Q

how do most colorectal cancers develop?

A

progression of normal mucosa to colonic adenoma to invasive adenocarcinoma

adenomas can be present for 10 years before they become malignant

progression to adenocarcinoma occurs in 10% of adenomas

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4
Q

what are the genetic mutations associated with predisposing individuals to colorectal cancer?

A
  • Familial adenomatous polyposis - malfunctioning Adenomatous polyposis coli (APC)
  • Hereditary nonpolyposis colorectal cancer (HNPCC)
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5
Q

what is Familial adenomatous polyposis?

A

autosomal dominant condition involving malfunctioning tumour suppressor genes called Adenomatous polyposis coli (APC)

results in polyps (adenomas) developing in the large intestine - polyps have potential to become cancerous

pt have their entire large intestine removed prophylactically to prevent development of bowel cancer - panproctocolectomy

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6
Q

what is HNPCC?

A

autosomal dominant

results from mutations in DNA mismatch repair genes

patients are at higher risk of number of cancers - esp colorectal

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7
Q

risk factors of colorectal cancer

A
  • 75% are sporadic
  • increasing age
  • family history
  • inflammatory bowel disease
  • low fibre diet
  • high processed meat intake
  • smoking
  • high alcohol intake
  • obesity and sedentary lifestyle
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8
Q

clinical features of colorectal cancer

A
  • Change in bowel habit
  • Rectal bleeding
  • Weight loss (associated with metastatic disease)
  • Abdominal pain
  • Iron-deficient anaemia
  • Abdominal or rectal mass on examination
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9
Q

features of right-sided colon cancer

A

abdominal pain
occult bleeding/anaemia
mass in RIF
often presents late

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10
Q

features of left-sided colon cancer

A

rectal bleeding
change in bowel habit
tenesmus
mass in LIF or on PR exam

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11
Q

what is the NICE guidance on referring ? bowel cancer?

A
  1. ≥40yrs with unexplained weight loss and abdominal pain
  2. ≥50yrs with unexplained rectal bleeding
  3. ≥60yrs with iron‑deficiency anaemia or change in bowel habit
  4. Positive occult blood screening test
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12
Q

how may someone with bowel cancer present acutely?

A

obstruction if the tumour blocks the passage through the bowel

surgical emergency - vomiting, abdo pain, absolute constipation

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13
Q

what are some differentials for colon cancer?

A

inflammatory bowel disease - average age of onset 20-40 yrs, typically presents with bloody, mucusy diarrhoea
haemorrhoids - bright red rectal bleeding on surface of stool but rarely presents with pain, altered bowel habits or weight loss

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14
Q

when is screening for bowel cancer offered in the uk?

A

every 2 years to men and women aged 60-74

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15
Q

what test is used in bowel cancer screening?

A

faecal immunochemistry test (FIT)
(supersedes faecal occult test)
uses antibodies against human haemoglobin to detect blood in faces

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16
Q

what is FIT and how does it work?

A

uses antibodies against human haemoglobin to detect blood in faces

can be used in GP to assess for bowel cancer in pt who do not meet criteria for 2ww

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17
Q

what happens if a patients FIT sample is positive?

A

offered an appointment with a specialist nurse to further investigate via colonoscopy

18
Q

The NHS Bowel Cancer Screening Programme has increased detection of colorectal cancer in people aged 60-69 by what %?

A

11%

19
Q

what laboratory tests are required?

A

routine bloods - FBC + may show microcytic (iron-deficiency) anaemia, LFTS & clotting
tumour markers NOT USED

20
Q

why is the tumour marker Carcinoembryonic Antigen (CEA) not used as a test?

A

poor sensitivity and specificity

21
Q

what is Carcinoembryonic Antigen (CEA) used for?

A

monitoring disease progression - conducted pre and post treatment

may be used for predicting relapse in patients previously treated for bowel cancer

22
Q

what is the gold standard for diagnosis of colorectal cancer?

A

colonoscopy with biopsy

involves endoscopy to visualise the entire large bowel

biopsy suspicious lesion or tattoo in preparation for surgery

23
Q

why might colonoscopy not be suitable for a patient?

A

frailty
co-morbidities
intolerance

24
Q

what is used in patients who cannot tolerate colonoscopy?

A

flexible sigmoidoscopy - rectum and sigmoid colon only - may be used when there is only rectal bleeding - risk of missing cancers in other parts of the colon

CT colonography - ct scan with bowel prep and contrast to visualise the colon in more detail - less detail and does not allow for biopsy

25
Q

what investigations are required for staging once the diagnosis has been made?

A
  • *CT scan** - chest abdo pelvis to look for distant metastases and local invasion full colonoscopy or CT colonogram is required to check for a 2nd (synchronous) tumour if not used initially)
  • *MRI rectum** (rectal cancers only)- depth and invasion and potential need for pre-op chemotherapy
  • *endo-anal USS** (T1 or T2 rectal caner) - asses suitability for trans-anal resection
26
Q

what staging is used for colorectal cancer?

A 
TNM system (like most cancers) 
T = depth the tumour invades the bowel wall 
N = extent of spread to local lymph nodes 
M = metastasis or not 
Dukes staging used in some places
27
Q

what are the Dukes’ stages and their associated survival %

A

been replaced by TNM

A = Confined beneath the muscularis propria = 90% 5 year survival 
B = Extension through the muscularis propria = 65% 5 year survival 
C = Involvement of regional lymph nodes = 30% 5 year survival 
D = distant metastasis = \<10% 5 year survival
28
Q

describe the TNM staging

A

T for Tumour:

  • TX – unable to assess size
  • T1 – submucosa involvement
  • T2 – involvement of muscularis propria (muscle layer)
  • T3 – involvement of the subserosa and serosa (outer layer), but not through the serosa
  • T4 – spread through the serosa (4a) reaching other tissues or organs (4b)

N for Nodes:

  • NX – unable to assess nodes
  • N0 – no nodal spread
  • N1 – spread to 1-3 nodes
  • N2 – spread to more than 3 nodes

M for Metastasis:

  • M0 – no metastasis
  • M1 – metastasis
29
Q

what is the curative management of colon cancer?

A

surgery - suitable regional colectomy to ensure removal of the primary tumour with adequate margins and lymphatic drainage followed by primary anastomosis or formation of a stoma

30
Q

what is a right hemicolectomy or extended right hemicolectomy and when is it used?

A
  • caecal tumours or ascending colon tumours
  • removal of caecum, ascending and (proximal) transverses colon
  • extended option performed for any transverse colon tumours.
  • During procedure the ileocolic, right colic, and right branch of the middle colic vessels (branches of the SMA) are divided and removed with their mesenteries.
31
Q

what is a left hemicolectomy and when is it used?

A
  • descending colon tumours
  • removal of distal transverse and descending colon
  • Similar to the right hemicolectomy, the left branch of the middle colic vessels (branch of SMA/SMV), the inferior mesenteric vein, and the left colic vessels (branches of the IMA/IMV) are divided and removed with their mesenteries.
32
Q

what is a sigmoidcolectomy - aka high anterior resection

A
  • sigmoid colon tumours.
  • remove sigmoid colon
  • In this instance, the IMA is fully dissected out with the tumour in order to ensure adequate margins are obtained
33
Q

what is a low anterior resection?

A

removal of sigmoid colon and upper rectum but sparing lower rectum and anus

34
Q

what is an abdominoperineal resection (AP) and when is it used?

A

low rectal tumours, typically <5cm from the anus.

This technique involves excision of the distal colon, rectum and anal sphincters, resulting in a permanent colostomy

35
Q

What is Hartmann’s Procedure and when is it used?

A

emergency bowel surgery - in bowel obstruction or perforation

complete resection of the recto-sigmoid colon with the formation of an end colostomy and the closure of the rectal stump

colostomy can be permanent or reversed at a later date

36
Q

what are some complications associated with bowel cancer surgery?

A
  • Bleeding, infection and pain
  • Damage to nerves, bladder, ureter or bowel
  • Post-operative ileus
  • Anaesthetic risks
  • Laparoscopic surgery converted during the operation to open surgery (laparotomy)
  • Leakage or failure of the anastomosis
  • Requirement for a stoma
  • Failure to remove the tumour
  • Change in bowel habit
  • Venous thromboembolism (DVT and PE)
  • Incisional hernias
  • Intra-abdominal adhesions
37
Q

what is low anterior resection syndrome?

A

may occur after resection of portion of bowel from the rectum, with anastomosis between colon and rectum

can result in a number of symptoms:

  • urgency and frequency of bowel movements
  • feacal incontinence
  • difficulty controlling flatulence
38
Q

when is chemotherapy indicated?

A

patients with advanced disease

39
Q

what is an example of a chemotherapy regime for patients with metastatic colorectal cancer?

A

FOLFOX
Folinic acid
Fluorouracil
Oxaliplatin
demonstrated to significantly improve 3 year disease free survival for patients with advanced colon cancer

40
Q

why is radiotherapy rarely used in colon cancer and when is it used?

A
  • risk of damage to the small bowel
  • used as neo-adjuvant treatment
  • used for patients with rectal cancers which look on MRI to have threatened circumferential resection. undergo pre op long course chemo-radiation to shrink tumour - increases chance of complete resection and cure
41
Q

what is the focus of palliative care in colon cancer?

A

reducing cancer growth and ensuring adequate symptom control

can have surgery to reduce symptoms and reduce size of tumour

42
Q

what are the palliative care options for patients with colon cancer?

A

endoluminal stenting - relieve acute bowel obstruction in patients with left-sided tumours
stoma formation - acute obstruction relief
resection of secondaries - can be done with adjuvant chemotherapy for any liver mets

Cancer Care (11 decks)

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