Screening and Early Diagnosis of

Colorectal Cancer

Shaimaa M.NagyFaculty of Medicine, Benha University

Incidence of CRCCRC is the 3rd most common form of cancer diagnosed

in men and women in the USCRC is the 2nd leading cause of cancer deaths in the USThe number of people dying from CRC has declined

over the past 20 years with better screening, diagnosis and treatments

ch.ch. of CRC in Egypt:

• Relative frequency 10-12%• High male predominance 3:1• More than 1/3 under age 45 (early onset)• Large tumor size 4.5 cm• rectal 51%, poor histology 58%• Associated bilharzial colitis 12%• Associated polyps 5%• Sporadic , HNPCC

Symptoms and signs A change in bowel habits: diarrhea, constipation, or a feeling that

the bowel does not empty completely

Bright red or dark blood in the stool

Stools that appear narrower or thinner than usual

Discomfort in the abdomen, including frequent gas pains, bloating, fullness, and cramps

Unexplained weight loss, constant tiredness, or unexplained anemia (iron deficiency)

Colorectal Cancer

80% present with early disease

20% present with metastatic disease.

Among patients diagnosed with early-stage disease, 40% will suffer recurrence.

Stage at Diagnosis

Localized(Stage I/II)

50%

Distant(Stage IV)

20%

Regional(Stage III)

30%

Risk Factors for CRC

• Age >50 (average risk)• Racial, ethnic factors

– African-Americans have increased risk• Dietary factors

– high animal fat, low fiber diet• Lifestyle

– Sedentary– Obesity– Smoking– Alcohol

-genetic factors-sporadic

Lifestyle Risk Factors for Colorectal Cancer

· Decrease Risk- Exercise- Folic acid- Aspirin- Calcium, vitamin D- Screening

· Increase Risk- Obesity- Red meat- Alcohol- Smoking

Colorectal Cancer (CRC)

Sporadic (average risk) (75-80%)

Familyhistory(10-15%)

Hereditary non-polyposis colorectal cancer (HNPCC)

(3-5%)Familial adenomatous polyposis (FAP) (1-2%)

Rare syndromes

(<0.1%)

Precancerous lesions:

PolypsIBD

Histological classification of polypstype single multiple

neoplastic Adnoma ( T,V,TV)adenocarcinoma

adenomatosis

hyperplastic hyperplastic Hyperplastic polyposis

hamartomatous Juvenile polypPeutz-jegher syndrom

Peutz jegher cowden

inflammatory Parasiticpsuedolymphoid

Parastic, inflammatory

Natural History

Polyp Advanced cancer

• Age 50, 25% risk of developing polyps• Age 75, 50-75% risk of developing polyps

IBD: Classification of Dysplasia

• Negative for dysplasiaNormalInactive colitisActive colitis• Indefinite for dysplasia• Positive for dysplasiaLow-grade dysplasiaHigh-grade dysplasia

Carcinoma in InflammatoryBowel Disease

• Extensive colitis 13%• < 10 years < 1%• 15 years 4.5%• 20 years 13%• 30 years 34%• Crohn’s disease 3%

Colorectal Cancer and Early DetectionColorectal cancer can be prevented through regular

screening and the removal of polyps

Early diagnosis means a better chance of successful treatment

Screening should begin at age 50 for all “average risk” individuals or sooner if you have a family history of colorectal cancer, symptoms, or a personal history of inflammatory bowel disease

Screening Methods for Colorectal Cancer History and general examination • Rectal examination

Colonoscopy (currently the best way to prevent and detect colorectal cancer)

Virtual colonography

Sigmoidoscopy

Fecal occult blood test

Double contrast barium enema

Digital rectal examination • Serum CEA, CA 19-9, CA 72.4 CBC, ESR, Ca and folic acid detection

Fecal Occult Blood Test (FOBT)Recommended to be done yearlyChecks for hidden blood in the stoolYour doctor gives you a test kit

At home, you place a small amount of your stool from 3 bowel movements on test cards.

You then return the cards to your doctor’s office or a lab where the stool samples are tested for hidden blood.

If blood is found, a colonoscopy will be needed.A disadvantage of this test

The test is often negative in people who have adenomatous polyps and colorectal cancer

Flexible Sigmoidoscopy (Flex Sig)Recommended every 5 yearsExamines the lining of rectum and lower part of colonUses a thin, flexible, lighted tube called a sigmoidoscope

It is inserted into your rectum and lower part of your colon.If polyps or lesions are found, a follow-up test is needed.

Disadvantages:Patient discomfort – but not painfulOnly looks at lower part of colon, therefore polyps in the

upper colon can go undetected.If a polyp is found, it needs to be followed by a colonoscopy to

remove the polyp

Combination FOBT and Flex SigSome experts recommend using both of these tests to

increase the chance of finding polyps and cancers. It is recommended every 5 years

ColonoscopySimilar to the Flexible Sigmoidoscopy except:

It allows the doctor to look at the lining of your rectum and entire colon.

Done as an outpatient procedureDone with “conscious sedation”

An IV line is inserted to help you remain calm and comfortable. Some patients sleep though the procedure.

Not everyone needs sedation. Uses a thin, flexible, lighted tube called a colonoscopeIt is inserted into your rectum and colon. The doctor can also find and remove polyps and some cancers

using the colonoscope. It is recommended every 10 years for:

Individuals with no family or personal history of colon cancer and no symptoms.

Colonoscopy (continued) …Procedure takes 15–30 minutes.May take longer if polyps are removed.

Called a polypectomy A wire loop is passed through the scope to cut the polyp

from the lining of the colon using an electrical current. Polyps are collected and sent to the

lab for evaluation.

Double Contrast Barium Enema (DCBE)This test allows the doctor to see an x-ray image of

the rectum and entire colon.First you are given an enema with a liquid called

barium that flows from a tube into your colon, followed by an air enema.

The barium and air create an outline around your colon, allowing the doctor to see if anything is wrong.

Recommended every 10 years. Many disadvantages:

Detects only 50 percent of adenomatous polyps greater than 1 cm in size and only 33 percent of polyps .5 cm in size

May miss up to 15 percent of colorectal cancers

Does not allow removal of polyps

Take Home Message

Screening = Prevention & Early Detection

Prevention = polyp removalDecreased Incidence

Early Detection Decreased Mortality

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