Colorectal Cancer

Question 1

Colorectal Cancer Definition

Answer 1

• Cancer that begins in the colon or rectum
• Results from pathologic changes that transform normal cells into invasive carcinoma
• Genetic and environmental influences

Question 2

Colorectal Cancer Epidemiology

Answer 2

• 3rd most common cancer among men and women
• 3rd leading cause of cancer death among men and women
• Lifetime risk: 1 in 19

Question 3

Colorectal Anatomy

Answer 3

• Colon has four sections: ascending colon (+cecum), transverse colon, descending colon, and sigmoid colon
  
  • Proximal colon (“right” sided) = ascending and transverse colon
  • Distal colon (“left” sided) = descending and sigmoid colon

Question 4

Colorectal Cancer Clinical Presentation

Answer 4

1. Asymptomatic
   
   • Majority of early cancers
   • Screening is key in early detection
2. Suspicious symptoms and/or signs
   
   • Majority of CRC diagnosed after symptom onset
   • Usually indicates more advanced CRC
   • Symptoms/signs from local tumor and/or metastasis
3. Emergent admission
   
   • Intestinal obstruction, peritonitis, acute GI bleed
   • Advanced disease

Question 5

Symptoms/signs from local tumor vs metastisis

Answer 5

• Localized
  
  • Left sided (early stage tumors):
    
    • Tend to have more symptoms
    • Smaller lumen, solid stool
    • Obstructive symptoms
    • Change in bowel
    • Hematochezia
  • Right sided (later stage tumors)
    
    • Larger lumen, liquid stool
    • Iron deficiency anemia (occult)
• Metastasis
  
  • Mets to liver, lungs brain, lymph nodes
    
    • Abdominal distension
    • RUQ pain
    • Early satiety
    • Supraclavicular adenopathy

Question 6

Colorectal Risk Factors

Answer 6

1. Age
2. Race/ethnicity
3. Gender
4. Lifestyle and dietary factors
5. Family or personal history of CRC
6. Colorectal polyps
7. Polyposis syndromes
8. Hereditary non polyposis colorectal cancer (HNPCC)
   
   • Lynch Syndrome
9. Inflammatory bowel disease

Question 7

Colorectal Cancer by Risk Type

Answer 7

1. Sporadic (75%)
   
   • No identifiable risk factors in individuals over age 50
2. Familial cases (15%)
   
   • A family history of CRC but no identified gene
3. Hereditary CRC
4. IBD

Question 8

Risk Factors: Age, Gender, Race

Answer 8

• Age
  
  • Incidence and death rates for CRC increase with age
  • 90% of new cases and 93% of deaths occur in people 50+, average age of diagnosis is 60
• Gender
  
  • Incidence and mortality rates are 30-40% higher in men than women
• Race/Ethnicity
  
  • CRC rates are highest in African Americans and Jews of Eastern European descent (Ashkenazi Jews)
  • Start screening at age 45

Question 9

CRC Modifiable Risk Factors

Answer 9

• Physical activity
• Obesity/overweight
• Red meat consumption
• Alcohol consumption
• Calcium/dairy product intake
• Vitamin D serum levels
• Dietary fiber and whole grains
• Daily fruit/vegetable intake
• Smoking
• Medications: NSAIDS, ASA, hormone replacement

Question 10

CRC Risk Factors: Family History

Answer 10

• Assess for familial CRC - no gene identified
  
  • CRC or advanced adenoma (>1cm) in any first-degree relative before age 60, or in 2 or more first-degree relatives at any age
  • Start screening at age 40, or 10 years before the youngest case in the immediate family
  • Screen every 5 years with colonoscopies
• Assess for hereditary CRC
  
  • Autosomal dominant conditions
    
    • Familial adenomatous polyposis and Lynch Syndrome
    • Very high risk for CRC!

Question 11

Hereditary Colon Cancer

Answer 11

• Polyposis syndromes
  
  • Familial adenomatous polyposis (FAP)
    
    • 100% risk of CRC, dx before age 50
    • >100 adenomatous polyps
    • Begin screening at age 12
    • Colectomy recommended if gene +
• Hereditary non polyposis colorectal cancer (HNPCC)
  
  • Lynch Syndrome
    
    • 52-69% risk of CRC, dx age 30-40s
    • Begin screening at age 20-25 yrs, or 10 years before the youngest case in the immediate family
    • Colonoscopy ever 1-2 years
    • Ovarian, endometrial, pancreatic, bile duct cancers are also linked to Lynch Syndrome

Question 12

CRC Risk Factors: Colorectal Polyps

Answer 12

• Polyp: any protrusion from an epithelial surface
  
  • Most CRCs begin as polyps
  • The most common kind of polyp = adenomatous polyp or adenoma
  • Adenomas arise from glandular cells (mucosal lining)
  • Fewer than 10% are estimated to progress to cancer
  • Most colorectal cancers are adenocarcinomas
• Polyp size, microscopic appearance, and number matter!
  
  • >1cm and villous component increases cancer risk
  • different follow-up is required

Question 13

CRC Risk Factors: IBD

Answer 13

• Ulcerative colitis and Crohn’s
• Cancer risk increases after 8 years with pan-colitis, or 12-15 years with left-sided colitis
• Screen every year with multiple biopsies
• Extent of disease, inflammation, and duration influence risk of CRC
• Colectomy for high-grade dysplasia recommended

Question 14

Colorectal Cancer Screening: average risk patients

Answer 14

• Begin screening at age 50
• The best test is the one that the patient will do
  
  • Colonoscopy = preferred
  • Sigmoidoscopy
  • Barium enema with air contrast
  • Virtual colonoscopy
  • FOBT
  • Stool DNA
• Follow-up colonoscopy is required if any abnormalities are shown with other tests

Question 15

Colorectal Cancer Screening: increased risk patients

Answer 15

• Earlier screening with best available test
• Colonoscopy is the recommended test

Question 16

CRC Complications

Answer 16

• Cancer-related: metastasis, perforation, peritonitis, obstruction
• Treatment-related:
  
  • Chemotherapy: nausea/vomiting, hair loss, neuropathy, low cell counts, cardiotoxicity, nephrotoxicity, mouth sores, fatigue, secondary cancers
  • Radiation (pelvic): nausea, diarrhea, rectal and bladder irritation, secondary cancers, decreased bone density, fractures
  • Surgery: colostomy, diarrhea or constipation