Colon Cancer Screening with Colonoscopy

See Also

Efficacy

Identifies up 94-98% of Colon Cancer
1. Bressler (2007) Gastroenterology 132(1): 96-102 [PubMed]
Identifies up to 98% of adenomatous polyps >1 cm (but only 74% <6mm)
1. van Rijn (2006) Am J Gastroenterol 101(2): 343-50 [PubMed]
Efficacious and reduces mortality
Preferred over other Colon Cancer screening modalities
Reference
1. Mandel (1993) N Engl J Med 328:1365-9 [PubMed]
2. Lieberman (2000) N Engl J Med 343:207-8 [PubMed]

Interpretation
Criteria for a high quality Colonoscopy

Minimal fecal residue following colon preparation
Colonoscopy reaches the cecum
Withdrawal time from cecum to Rectum is 6 minutes or more
Complete removal of identified polyps (not piecemeal excision)
Rex (2002) Am J Gastroenterol 97:1296-1308 [PubMed]

Adverse Effects

Minor common adverse effects
1. Adverse effects of preparation medications
2. Adverse effects of sedation
Serious common adverse effects
1. Perforations: 1 in 500-3000
  1. Rectosigmoid: 66%
  2. Cecal: 13%
  3. Ascending Colon: 7%
  4. Transverse Colon: 7%
  5. Descending Colon: 7%
2. Major Bleeding: 1-2 in 1000 (0.1 to 0.6%)
  1. Most common with biopsy or lesion excision
  2. May occur up to 2 weeks after Colonoscopy
3. Post-polypectomy Syndrome
  1. Abdominal Pain, Leukocytosis, peritoneal inflammation without perforation
  2. Onset within 2 weeks of polypectomy
Uncommon
1. Splenic Trauma
2. Vasovagal reaction
3. Endocarditis
Rare
1. Sepsis

Findings
Polyps

See Colonic Polyps

Protocol
Home Medications Before Colonoscopy

See Bowel Preparation
No Antibiotic prophylaxis is needed in most cases
1. Not indicated despite cardiac conditions, prosthetic joints, or vascular grafts
Anticoagulants
1. Low dose Aspirin and NSAIDS
  1. Typically may be continued for all endoscopic procedures
  2. However, local protocols vary, and some may require Aspirin and NSAIDs be stopped first
  3. However, stable patients on Dual Antiplatelet Therapy will typically have Aspirin continued, and other agent held
2. Antiplatelet Agents (Clopidogrel, Prasugrel, Ticagrelor)
  1. Low risk of bleeding (e.g. routine Colonoscopy)
    1. These agents are stopped in most cases, but may be continued if higher thrombosis risk
    2. Dual Antiplatelet Therapy patients who are stable
      1. Constinue low dose Aspirin and hold the other antiplatelet agent as below
  2. High risk of bleeding
    1. Low risk of thrombosis
      1. Stop Clopidogrel or Prasugrel for 5-7 days
      2. Stop Ticagrelor for 3-5 days
    2. High risk of thrombosis (e.g. drug eluting stent placed in the last year)
      1. Delay procedure
  3. Restarting after procedure
    1. No polyps removed: May restart immediately
    2. Polyps removed: Restart 24 hours after procedure
3. Warfarin
  1. Low risk of bleeding (e.g. routine Colonoscopy): May continue Warfarin
  2. High risk of bleeding
    1. Low risk of thrombosis: Stop Warfarin for 5 days before procedure
    2. High risk of thrombosis (e.g. Mechanical Heart Valve, VTE within 3 months)
      1. Delay procedure OR
      2. Warfarin bridging with Heparin stopped 4-6 hours before procedure
  3. Restarting after procedure
    1. No polyps removed: May restart immediately
    2. Polyps removed: Restart 12 hours after procedure
4. Direct Oral Anticoagulants (DOACs, Apixaban, Rivaroxaban)
  1. Hold 1-2 before procedure (if normal Renal Function)
  2. Restarting after procedure
    1. No polyps removed: May restart immediately
    2. Polyps removed: Restart 48-72 hours after procedure
Diabetes Medications
1. Day prior to Colonoscopy
  1. Hold Sulfonylureas (e.g. Glipizide), Non-Sulfonylurea Insulin Secretagogues (e.g. Nateglinide)
  2. Consider decreasing evening premixed Insulin (e.g. 70/30) or Basal insulin by 50%
  3. Decrease Bolus Insulin by 50% (may use full Bolus Insulin dose if Carbohydrate Counting)
  4. May continue all other diabetes medications on day prior
2. Day of Colonoscopy
  1. Consider giving partial Basal insulin dose on morning of procedure (esp. in Type I Diabetes Mellitus)
  2. Hold all other diabetes medications on the morning of procedure
Other Medications
1. Most other medications may be taken with a sip of water up to 3 hours before Colonoscopy

Management
Suspected colonoscopic perforation

Indications for immediate laparotomy
1. Peritoneal signs
2. Unreliable patient or comorbid conditions
3. Large defect
4. Poor Bowel Preparation
Evaluation of stable, reliable patient
1. Step 1: Obtain upright abdominal XRay
  1. Laparotomy for Free air
2. Step 2: Obtain CT Abdomen
  1. Laparotomy for large perforation
3. Step 3: Observe
  1. Indications
    1. Negative upright Abdomen
    2. Negative CT or contained perforation on CT
  2. Conservative protocol
    1. Patient kept NPO on Intravenous Fluids
    2. Prophylactic Antibiotics
    3. Serial exams, XRays, and White Blood Cell Count
  3. Laparotomy Indications
    1. Clinical deterioration
    2. Increased White Blood Cell Count

References

(2022) Presc Lett 29(5): 27
Kavic (2001) Am J Surg 181:319-32 [PubMed]
Wilkins (2018) Am Fam Physician 97(10): 658-65 [PubMed]