Colon CancerEpidemiology, screening, prevention, and treatment options

Fadi Annaba, MD

www.SpringfieldClinic.com/DoctorIsIn

Colon Cancer• A common and lethal cancer. 3rd. Most common in males,

2nd in females.• The 2nd leading cause of cancer death in the US.• 1:20 life time chance of CRC in an average risk individual• Most cases (90%) happen after age 50.• About 50,000 patient die annually of CRC. 9% of all

cancer deaths combined.• Influenced by both genetics and environmental factors

• Incidence decreased 2-3% per year over the past 15+ years in the US, and death rates have been progressively decreasing since the mid-1980s, largely due to screening and removal of polyps.

• 25% higher in males than females, and 20% higher in African-Americans than whites.

• A gradual shift has been noted toward more right colon, especially cecal lesions.

http://www.cancerresearchuk.org/cancer-info/cancerstats/types/bowel/survival/bowel-cancer-

survival-statistics

Risk factors• Environmental (modifiable), and genetic.• It is important to understand that the majority of cases

are sporadic and not inherited.• Obesity• Smoking• Physical inactivity• Diet• Age• Family history of colon cancer.

Risk Factors• FAP (Familial Adenomatous Polyposis): Less than 1%.• HNPCC (Hereditary Non-Polyposis Colorecal Cancer),

also called Lynch Syndrome: ~ 4%.• Personal history of prior CRC.• Family history of colon cancer: 1st degree relative

affected increase patient risk by about two folds. Risk increases further if more than one 1st degree affected or if affected family member younger than age 60.

Risk Factors

• Personal history of previous adenomatous polyps.• Family history of advanced polyps (> 1cm, villous

component), multiple adenomas, or early onset of adenomas.

• Personal history of Ulcerative or Crohn’s colitis.• Childhood history of abdominal radiation.• Acromegaly.

Effect of age on CRC incidence

Prevention• Physical activity.• Better diet (high fiber, vegetable and fruits, low in

red meat, low saturated and animal fat, high in fish oils, enough calcium and Vit D)

• Smoking cessation.• Healthy body weight (BMI 18-25)• ASA and NSAIDS• Screening at recommended intervals.

When to start screening

• Age 50 in average risk individuals.• Age 45 in African Americans.• Age 40 if family history of advanced adenomatous

polyps prior to age 60• Age 40 -or 10 years younger than affected family

member age- whichever is earlier, if history of colon cancer in 1st degree relative.

How frequently to screen• Every 10 years in average risk patients who have

no adenomas on a quality exam.• Every 5 years in patients with family history of

colon Cancer• Every 5 years in patients with adenomatous polyps• In 3 years after resection of an advanced adenoma,

or multiple small adenomas.• Every 3-4 years in acromegaly patients.• Every 2 years in colitis patients.

Screening modalities

• Stool occult blood• Double contrast Barium enema (DCBE)• CT-colography (CTC)• Sigmoidoscopy• Colonoscopy

Stool occult blood

• Help detects early cancers and possibly advanced adenomas.

• High false- negative for polyps, and false-positive (bleeding from a non-cancerous lesion)

Double Contrast Barium Enema (DCBE)

• Detects 39% of all polyps, and only about half of advanced polyps (high rate of false neg)

• Misses about 20% of CRC cases.• Some discomfort (no sedation)• Lesions found still need to be inspected and

removed if confirmed.

CT-Colography (CTC) A.K.A Virtual Colonoscopy

• Better detection rate than DCBE • No sedation• Needs bowel prep• Helps screening right colon when incomplete

colonoscopy (1-2%)• Small lesions especially flat are more difficult to detect.• False positive have to be confirmed with colonoscopy.• Extra-colonic findings.

Sigmoidoscopy

• Screens mainly left colon to splenic flexure. i.e. can’t screen right colon.

• Direct visualization of colonic mucosa with ability to perform biopsies, polypectomy, and EMR.

• Can be carried out without sedation in some patients.

• Needs bowel prep.

Colonoscopy• Screens the entire colon in almost all cases.• Direct visualization of colonic mucosa with ability

to perform biopsies, polypectomy, and EMR.• Is considered the preferred test.• Requires sedation in most cases.• Needs bowel prep.• Takes about 30-45 minutes to finish on average.

• http://www.hcplive.com/articles/Study-Recommends-Standardization-of-Colonoscopy-Training

Wikimedia

Complications of Colonoscopy

• Sedation-related.• Perforation• Bleeding• Occur in about 1 in 1000 cases. Most are minor and

transient, but some require further interventions.

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