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Year 3 TCDs > Bowel Cancer > Flashcards

Bowel Cancer Flashcards

1
Q

List some of the common causes for fresh blood in stools

A
  1. Hemorrhoids
  2. Acute anal fissure (following trauma or severe constipation)
  3. Colo-rectal neoplasms
  4. Acute proctitis
  5. Inflammatory bowel disease
  6. Gastroenteritis
  7. Malabsorption (pancreatic insufficiency, celiac disease)
  8. STIs
  9. Other masses (I.e. bladder ,uterus, ovary)
  10. Anal cancer
  11. Other causes of mass in rectum (cervix/prostate)

Fresh bleeding usually suggests the rectum or the anal canal as a source of bleeding. Bleeding from further up the GI tract (colon, small intestine or stomach) usually is mixed with stools + presents as malena unless it’s profuse

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2
Q

What is acute anal fissure?

A

Acute anal fissure refers to a condition where there is a break or tear in the skin of the anal canal. It is associated with severe pain- usually when passing hard faeces sometimes with bright red anal bleeding observed on the toilet paper or in the toilet. Chronic fissures may become less painful over time. Fissures extend from the anal opening and are usually directed posteriorly in the midline, probably because the anal wall is poorly supported posteriorly. Rarely fissures may extend down to the underlying sphincter muscles.

Anal fissures are a common cause for painful rectal bleeding in constipated subjects. Bleeding is rarely severe enough to cause anaemia. If such patients are found to be anaemic, it is important to consider other underlying causes.

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3
Q

When should a patient be referred using a suspected cancer pathway (appointment within 2 weeks) for colorectal cancer?

A

If:
1. Over 40 with unexplained weight loss + abdo pain

  1. Over 50 with unexplained rectal bleeding
  2. Over 60 with iron-deficiency anemia or changes in their bowel habits
  3. Tests show occult blood in feces

Consider referral in patients with rectal/abdo mass.

Consider referral in patients under 50 with rectal bleeding and any of the following:

  • Abdo pain
  • Change in bowel habit
  • Weight loss
  • Iron-deficiency anemia
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4
Q

How big a problem is colon cancer in the UK? Or what is the disease burden?

A

Colorectal cancer is a common form of malignancy in developed countries but occurs much less frequently in the developing world.

It is the third most common cancer after breast and lung.

Around two-thirds of malignancies occur in the colon and one-third in the rectum. Within the colon itself, more tumours are diagnosed in the left half of the colon than in the right side with the recto-sigmoid colon being the most frequent site (caecum is the second).

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5
Q

What should be considered in any elderly subject presenting with unexplained microcytic anemia?

A

Occult bleeding from a colonic malignancy

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6
Q

How is bowel cancer staged?

A

Dukes’ system

A = cancer is only in the innermost lining of the colon/rectum or slightly growing into the muscle layer

B = cancer has grown thru the muscle layer of the colon/rectum

C = cancer has spread to at least 1 lymph node in the area

D = cancer has spread somewhere else in the body, such as liver or lung. Aka stage 4/advanced bowel cancer.

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7
Q

Outside of Dukes’ system, what other systems may be used to stage bowel cancers?

A

TNM

Tumour
T1 = no further growth than the inner layer of the bowel

T2 = grown into the muscle layer of the bowel wall

T3 = grown into the outer lining of the bowel wall or into organs/body structures next to the bowel

T4 = grown into other parts other bowel/other organs/body structures near bowel

Lymph Nodes
N0 = no lymph node involvement

N1 = 1-3 lymph nodes close to the bowel contain cancer cells

N2 = 4+ lymph nodes contain cancer cells further than 3cm away from main tumour/connected to main blood vessels around the bowel

Metastases
M0 = no spread to other organs
M1 = cancer has spread to other parts of the body

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8
Q

What is a hemicolectomy?

A

A procedure in which the surgeon removes a part of the colon.

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9
Q

What is an ileostomy?

A

A stoma constructed by bringing the end or loop of small intestine out onto the surface of the skin. Intestinal waste passes out of the ileostomy and is collected in an artificial external pouching system.

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10
Q

What is a colostomy?

A

An opening in the large intestine/surgical procedure that draws the healthy colon into the anterior abdo wall and is stuck in place. It provides an alternative channel for feces to leave the body (I.e. artificial anus)

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11
Q

What is an anterior resection?

A

Surgery for rectal cancer removing the anterior part of the rectum and colon (upper 2/3 of rectum while leaving the rectal sphincter intact)

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12
Q

What is an abdominoperineal resection?

A

Surgery for rectal or anal cancer affecting the distal 1/3 of the rectum.

Involves the removal of the anus, the rectum and part of the sigmoid colon along with associated regional lymph nodes.

The end of the sigmoid colon is brought out permanently as an opening (colostomy) on the surface of the abdomen.

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13
Q

What is the 5y survival rate of colon cancer?

A

93% in Dukes’ stage A

< 7% of patients with advanced disease (Dukes D)

In patients with good physiological reserves, a combo of radical surgery + chemotherapy is also a viable option even with liver mets.

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14
Q

Which investigations are used to diagnose a colon cancer?

A
  • Barium enema
  • Flexible sigmoidoscopy (to visualise L colon)
  • Colonoscopy (expensive, risk of perforation/bleeding)
  • CT VC (virtual colonoscopy)
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15
Q

What is apc and FAP?

A

FAP = inherited mutation in 1 apc allele

  • Chromosome 5q
  • Affects 1 in 7000
  • Autosomal dominant (95% penetrance) cancer risk gene

Apc mutation in 80% sporadic adenomas/CRCs

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16
Q

Name 2 other genetic mutations that cause bowel cancer

A
  1. K ras
    - ONCA gene
  2. P53
    - tumour suppressor gene
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17
Q

What is HNPCC?

A

Hereditary Non Polyposis Colorectal cancer

  • Inherited mutation in mismatch repair genes
  • Genome is replication error prone (microsatellite instability)
  • Early bowel cancer (circa 30-50y)
  • Often affects proximal colon
  • Rapid adenoma-carcinoma progression
  • 70-80% penetrance
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18
Q

What is the criteria used to determine the chances of harbouring the HNPCC gene?

A

Amsterdam criteria

Uses family history

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19
Q

What area of the colon is most affected in colon cancer?

A
  1. Sigmoid colon
  2. Cecum
  3. Rectum
  4. Ascending colon
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20
Q

How is staging for colon cancer determined?

A
  • CT scan
  • MRI if thinking mets
  • PET scan if thinking mets
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21
Q

After a diagnosis of colon cancer how soon after is the cancer operated on?

A

2 months after diagnosis

- Segmental resection

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22
Q

What arteries supply the ascending colon and sigmoid colon?

A

Ileocolic artery + superior mesenteric vein

Sigmoidal artery + inferior mesenteric vein

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23
Q

What is the difference between ileostomy and colostomy?

A

Ileostomy:

  • Spouted
  • Often RIF
  • Continuous effluent
  • Liquid coming out into bag

Colostomy:

  • Not spouted
  • Often LIF
  • Periodic function
  • Solid coming out into bag
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24
Q

What additional therapy is proven to work in patients with Dukes C colon cancer after surgery?

A

6mo chemotherapy with 5FU

  • No role for radiotherapy
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25
Q

How is rectal cancer staged?

A

Local

  • Ultrasound
  • MRI

Systemic
- CT scan

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26
Q

When can a tumour be removed locally from rectum in a T1 lesion?

A

If < 3cm in size

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27
Q

What surgical procedure is most commonly used for rectal cancer?

A

Anterior resection

- Total mesorectal excision and anastomoses

28
Q

What adjuvant therapy would you use in T3 and T4 rectal cancer before surgery?

A

Radiotherapy for T3

Radiotherapy/chemotherapy for T4

29
Q

What are the different appearances of colonic malignancies?

A
  1. Ulcer
  2. Polyp
  3. Circumferential lesion
30
Q

What are diverticuli?

A

Outpourings of the colonic mucosa and submucosa through inherent weaknesses in the outer muscle layers.

The commonest site is the sigmoid colon possibly due to pressure effects associated with chronic constipation and/or accumulation of fecal matter

Note: Diverticular disease is asymptomatic in many patients and is often an incidental finding on other investigations.

31
Q

What are risk factors for diverticular disease of the colon?

A
  1. Hereditary factors
  2. Chronic constipation
  3. Increasing age
  4. High intake of meat and red meat
  5. Low fibre diet
32
Q

What are some frequent complications of colonic diverticuli?

A
  1. Infection -> diverticulitis
    - Similar to acute appendicitis with pain frequently located in LLQ/hypogastrium
  2. Bleeding (occult/overt)
  3. Perforation (very serious - possible leakage of feces giving rise to fecal peritonitis)
  4. Abscess formation (diverticular abscess similar to appendicular abscess)
33
Q

What are differentials for generalised abdominal pain?

A
  1. Perforated viscous
  2. Acute pancreatitis
  3. Medical causes (I.e. DKA)
34
Q

What are differentials for localised abdo pain to the RUQ?

A
  1. Gallbladder disease (cholecystitis, cholangitis, biliary colic)
  2. Duodenal ulcer
  3. Acute pancreatitis
  4. Medical disorders (pneumonia - referred pain)
35
Q

What are the differentials for LUQ pain?

A
  1. Acute pancreatitis
  2. Spontaneous splenic rupture
  3. Medical disorders (pneumonia)
36
Q

What are the differentials for RIF pain?

A
  1. Acute appendicitis
  2. Perforated duodenal ulcer
  3. Crohn’s Disease
  4. Diverticulitis
  5. Constipation
  6. Renal colic
  7. Obs & Gyn (ectopic pregnancy, ruptured ovarian cyst, salpingitis)
37
Q

What are the differentials for LIF pain?

A
  1. Diverticulitis
  2. Constipation
  3. Obs/Gyn (ectopic pregnancy, ruptured ovarian cyst, salpingitis)
38
Q

What are the differentials for epigastric pain?

A
  1. Peptic/duodenal ulcer

2. Acute pancreatitis

39
Q

What are the differentials for central abdominal pain?

A
  1. Early appendicitis
  2. Small bowel obstruction
  3. Acute pancreatitis
  4. Mesenteric thrombosis
40
Q

What are the differentials for suprapubic pain?

A
  1. Acute urinary retention
  2. UTI
  3. Ectopic pregnancy
41
Q

In what 3 conditions do you have colicky pain?

A
  1. Bowel obstruction
  2. Biliary colic
  3. Renal colic
42
Q

What are the 6 classic signs of acute abdomen?

A
  1. Fever (low grade)
  2. Tenderness
  3. Rigidity/guarding
  4. Rebound tenderness
  5. Bowel sounds - absent in peritonitis, increased in small bowel obstruction
  6. Abdominal distension: Fat, fluid, foetus, feces, flatus, fucking huge mass
43
Q

What are the investigations ordered for an acute abdomen?

A
  1. FBC
  2. U&E, LFTs
  3. CRP
  4. Serum amylase
  5. Serum glucose
  6. Blood gas + lactate
  7. Pregnancy test in women (always!)
  8. Urine dipstick (hematuria in UTI)
  9. Erect chest x-ray
  10. Supine abdominal film (CT abdo)
44
Q

On chest X-ray if you see free gas under the diaphragm on the R what does this indicate?

A

Perforation of a viscus

45
Q

What is the routine for AXR?

A
  1. Rectum
  2. Bowel
  3. Kidneys, ureters, and bladder (KUB)
  4. Upper GI organs
  5. Bones
46
Q

What is the normal gas pattern on AXR?

A

Stomach -> always gas present

Small bowel -> 2/3 loops of bowel

Sigmoid/rectum -> almost always

47
Q

What does the large bowel appear like? Small bowel?

A

Large bowel:

  • Sits peripherally
  • Haustral markings do not extend wall to wall

Small bowel:

  • Central
  • Valvulae extend across the lumen
48
Q

What is seen in colitis on AXR?

A
  • Thickening of colon

- Oedema in colonic wall (thick white line)

49
Q

What does toxic megacolon look like on AXR?

A
  • Whole sigmoid colon is distended over a diameter of 6cm (U-shaped sigmoid colon)
  • Require a total colectomy
50
Q

What does proximal constipation look like on AXR?

A

Pixelated appearance of colon

Needs laxative therapy

51
Q

What does SI obstruction look like on AXR?

A

Valvulae extend across the diameter of SI

No large bowel present

Small bowel dilatation

52
Q

What does sigmoid volvulus look like on AXR?

A

Coffee-bean sign

  • Abdomen massively distended
  • Twisted sigmoid colon
53
Q

What does cecal volvulus look like on AXR?

A

Twist in ascending colon leading to massively distended cecum

urgent surgical decompression to avoid perforation

54
Q

What is a hernia?

A

Occurs when an internal part of the body pushes through a weakness in the muscle or surrounding tissue wall.

55
Q

What is the most common form of hernia?

A

Inguinal hernia

  • Mostly affects men
  • Increase with age
  • Part of bowel pushes thru inguinal canal (passage from abdomen to scrotum)
56
Q

How are hernias treated?

A

Surgical operation:

  1. Open surgery
    - Cut in groin + pushed back thru weakspot
    - Mesh patch to reinforce the muscle
  2. Key whole surgery
    - Muscular weakness is repaired by putting mesh thru the abdominal wall
    - Repairs muscular weakness without going thru lining
57
Q

What should be considered if an elderly patient with AF is found with a profound metabolic acidosis and an acute abdomen?

A

Sign of bowel infarction caused by an embolism in the mesenteric artery.

Infarcts bowel presents with signs of obstruction + emergency surgery is needed.

58
Q

What are the 3 main symptoms of bowel cancer?

A
  1. Persistent blood in poo
  2. Persistent change in bowel habit (increased frequency + runny)
  3. Persistent lower abdo pain, bloating, or discomfort (caused by eating, loss of appetite, significant unintentional weight loss)
59
Q

What is the bowel cancer screening program in the UK?

A
  1. All men/women aged 60-74 are invited to carry out a FIT/FOB test.
    - Every 2y they’re sent a home test kit to collect a poo sample.
  2. Additional one-off test called bowel scope screening
    - Men/women at age 55y
60
Q

What are the 4 commonest differentials for acute abdomen pain?

A
  1. Adhesions
  2. Strangulated hernia
  3. Cholecystitis
  4. Gastric ulcer
61
Q

How can someone reduce their risk of bowel cancer?

A
  1. Participate in bowel screening when offered
  2. Maintain healthy weight
  3. Eat a diet high in non-starchy veggies, fruit, pulses, and whole grains, keeping red meat consumption to a minimum + avoiding processed meat
  4. Avoid alcohol
  5. Avoid smoking
  6. Regular physical activity (moderate intensity for a min of 30min 5d/week)
62
Q

Which symptoms are typical of acute appendicitis?

A
  1. Dull pain near the navel or upper/lower abdomen that becomes sharp as it moves to the RLQ
    - in 50% of cases
  2. Loss of appetite + N/V soon after pain begins
63
Q

What are the 6 red flags for colonic cancer?

A
  1. Change in bowel habit in person over 60y
  2. Unexplained weight loss
  3. Rectal bleeding
  4. Rectal/abdominal mass
  5. Anemia
  6. Family history of bowel cancer
64
Q

What 4 things are true about acute abdominal pain in the elderly?

A
  1. Tend to show less specific symptoms + signs
  2. Serious pathology more likely
  3. Morbidity + mortality are high
  4. AAA + bowel ischemia are more prevalent in the elderly
65
Q

What result is seen in bowel ischemia on a blood gas (ABG)?

A

Profound metabolic acidosis

Year 3 TCDs (24 decks)

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