Knowing Cancer of Colon

Colorectal Cancer

Dato’ Dr Minder Singh

Consultant Surgeon

KEDAH MEDICAL CENTRE

Outline

• Where is the colon and what does it do?• Why is colon cancer important?

• How many cases/year?• Who gets it?• Who dies from it?

• How does colon cancer develop?• How is colon cancer treated?• Is colon cancer preventable?

What is the Function of the Colon and Rectum?

• The colon and rectum comprise the large intestine (large bowel)

• The primary function of the large bowel is to turn liquid stool into formed fecal matter

What is Colorectal Cancer?

• Third most common type of cancer and second most frequent cause of cancer-related death

• A disease in which normal cells in the lining of the colon or rectum begin to change, grow without control, and no longer die

• Usually begins as a noncancerous polyp that can, over time, become a cancerous tumor

Colon; The Cancer Its Self

• It starts with a simple cell the mutates and grows into a polyps

• If a polyp is allowed to remain in the colon it can grow into a cancerous tumor that can invade other organs.

• Colon cancer is the second leading cause of cancer deaths

How Does Colorectal Cancer Develop?

Colon Polyp

Colon Cancer

What Are the Risk FactorsWhat Are the Risk Factors for Colorectal Cancer? for Colorectal Cancer?

• Polyps (a noncancerous or precancerous Polyps (a noncancerous or precancerous growth associated with aging)growth associated with aging)

• AgeAge• Inflammatory bowel disease (IBD)Inflammatory bowel disease (IBD)• Diet high in saturated fats, such as red meatDiet high in saturated fats, such as red meat• Personal or family history of cancerPersonal or family history of cancer• ObesityObesity• SmokingSmoking• OtherOther

What Are the Symptoms ofWhat Are the Symptoms ofColorectal Cancer?Colorectal Cancer?

• A change in bowel habits: diarrhea, constipation, or a A change in bowel habits: diarrhea, constipation, or a feeling that the bowel does not empty completelyfeeling that the bowel does not empty completely

• Bright red or dark blood in the stoolBright red or dark blood in the stool

• Stools that appear narrower or thinner than usualStools that appear narrower or thinner than usual

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

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

Symptoms of Colon Cancer

• Persistent• Constipation• Diarrhea• Blood in the Stool• Unexplained Fatigue

Colorectal Cancer and Early DetectionColorectal Cancer and Early Detection

• Colorectal cancer can be prevented through Colorectal cancer can be prevented through regular screening and the removal of polyps regular screening and the removal of polyps

• Early diagnosis means a better chance of Early diagnosis means a better chance of successful treatmentsuccessful treatment

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

How is Colorectal Cancer How is Colorectal Cancer Evaluated?Evaluated?

• Diagnosis is confirmed with a biopsyDiagnosis is confirmed with a biopsy

• Stage of disease is confirmed by pathologists Stage of disease is confirmed by pathologists and imaging tests, such as computerized and imaging tests, such as computerized tomography (CT or CAT) scanstomography (CT or CAT) scans

• Endoscopic ultrasound and magnetic Endoscopic ultrasound and magnetic resonance imaging (MRI) may also be used to resonance imaging (MRI) may also be used to stage rectal cancerstage rectal cancer

Is Colorectal Cancer Preventable?

YES!

• Screening

• Chemoprevention

Colon Cancer Preventions

• Colon cancer can be prevented and cured through early detection

• Changing your eating habits( more fiber and less fats)

• Don’t smoke and drink less

Screening Techniques for Colorectal Cancer

Fecal occult blood test (FOBT) every year, or

Flexible sigmoidoscopy every 5 years,or

A fecal occult blood test every year plus flexible sigmoidoscopy every 5 years (recommended by the American Cancer Society), or

Double-contrast barium enema every 5 to 10 years, or

Colonoscopy every 10 years (recommended by the American College of Gastroenterology).

Screening For Colon Cancer SAVES LIVES!!!

MortalityTest Reduction

Fecal occult blood testing 33%

Flexible sigmoidoscopy 66%(in portion of colon examined)

FOBT + flexible sigmoidoscopy 43%(compared to sigmoidoscopy alone)

Colonoscopy ~76-90%(after initial screening and polypectomy)

Colorectal cancer screeningFirst assess RISK

AVERAGE RISK INDIVIDUAL• All patients age 50 years and older, the

asymptomatic general population

HIGH RISK• Personal history – polyp or cancer• Family history – polyp or cancer in first

degree relatives

Fecal Occult Blood Testing

• Examination of stool for occult (“hidden”) blood

• Can detect one teaspoon or less of blood in a bowel movement

• Uses chemical reaction between blood and reagent

Double-contrast Barium Enema

Double-contrast Barium Enema

• Pros• Examines entire colon• Relatively low cost

• Cons• Never studied as a screening test• Missed 50% of polyps > 1cm in one study• Detects 50-75% of cancers in those with

positive FOBT• Interval between exams unknown

Winawer et al. Gastroenterology 1997; 112:599Rex, Endoscopy 1995; 27:200Lieberman et al. N Engl J Med 2000; 343:163

Sigmoidoscopy/Colonoscopy

Site Distribution

Flexible sigmoidoscopy• Pros

• May be done in office• Inexpensive, cost-effective• Reduces deaths from rectal cancer• Easier bowel preparation, usually done without

sedation• Cons

• Detects only half of polyps• Misses 40-50% of cancers located beyond the view

of the sigmoidoscope• Often limited by discomfort, poor bowel preparation

Selby et al N Engl J Med 1992; 336:653 Stewart et al Aust NZ J Surg 1999; 69:2Newcomb et al. JNCI 1992; 84:1572 Painter et al Endoscopy 1999; 3:269Rex et al. Gastrointest Endosc 1999; 99:727

Colonoscopy

• Pros• Examines entire colon• Removal of polyps performed at time of exam• Well-tolerated with sedation• Easier bowel preparation, usually done without

sedation• Cons

• Expensive• Risk of perforation, bleeding low but not negligible• Requires high level of training to perform• Miss rate of polyps < 1 cm ~25%, > 1 cm ~5%

Rex et al. Gastroenterology 1997; 112:24-8Postic et al. Am J Gastroenterol 2002; 97:3182-5

Chemopreventive agents

Fiber Not effective

Aspirin May be effective

NSAIDs (ibuprofen, etc) Probably effective

Vitamin E, vitamin C, beta carotene

Not effective

Folate Effective if obtained in diet

Calcium Effective

Estrogen Effective, but has other problems

Future techniques for colorectal cancer screening

• Stool DNA testing

• Capsule endoscopy (Givens capsule)

• CT colography (virtual colonoscopy)

Videocapsule

CT Colography

Colon Polyp

CT Colography

Colon Polyp

CT Colography

Colon Cancer

Cancer Treatment: SurgeryCancer Treatment: Surgery

• Foundation of curative therapyFoundation of curative therapy

• The tumor, along with the adjacent healthy The tumor, along with the adjacent healthy colon or rectum and lymph nodes, is typically colon or rectum and lymph nodes, is typically removed to offer the best chance for cureremoved to offer the best chance for cure

• May require temporary or (rarely) permanent May require temporary or (rarely) permanent colostomy (surgical opening in abdomen that colostomy (surgical opening in abdomen that provides a place for waste to exit the body)provides a place for waste to exit the body)

Surgery• Surgery or "resection" of the colon

involves cutting away the portion of the colon that is diseased, and reconnecting the two healthy parts (anastomosis).

Surgery• In a small percentage of patients with

colon cancer (about 15 percent) the surgeon will be unable to reconnect the healthy parts. In such a case, a temporary or permanent colostomy is used.

• A colostomy is a surgical opening (stoma) through the wall of the abdomen into the colon, which provides a new path for waste material to leave the body.

Cancer Treatment: ChemotherapyCancer Treatment: Chemotherapy

• Drugs used to kill cancer cellsDrugs used to kill cancer cells

• Typical medications include fluorouracil (5-FU), Typical medications include fluorouracil (5-FU), oxaliplatin (Eloxatin), irinotecan (Camptosar), and oxaliplatin (Eloxatin), irinotecan (Camptosar), and capecitabine (Xeloda)capecitabine (Xeloda)

• A combination of medications is often used A combination of medications is often used

Types of Chemotherapy

• Adjuvant chemotherapy is given after surgery Adjuvant chemotherapy is given after surgery to maximize a patient’s chance for cure to maximize a patient’s chance for cure

• Neoadjuvant chemotherapy is given before Neoadjuvant chemotherapy is given before surgerysurgery

• Palliative chemotherapy is given to patients Palliative chemotherapy is given to patients whose cancer cannot be removed to delay or whose cancer cannot be removed to delay or reverse cancer-related symptoms and reverse cancer-related symptoms and substantially improve quality and length of lifesubstantially improve quality and length of life

Cancer Treatment: Radiation Cancer Treatment: Radiation TherapyTherapy

• The use of high-energy x-rays or other The use of high-energy x-rays or other particles to destroy cancer cellparticles to destroy cancer cell

• Used to treat rectal cancer, either before or Used to treat rectal cancer, either before or after surgeryafter surgery

• Different methods of deliveryDifferent methods of delivery

• External-beam: outside the bodyExternal-beam: outside the body

• Intraoperative: one dose during surgeryIntraoperative: one dose during surgery

New Therapies: Antiangiogenesis New Therapies: Antiangiogenesis TherapyTherapy

• ““Starves” the tumor by disrupting its blood Starves” the tumor by disrupting its blood supplysupply

• This therapy is given along with This therapy is given along with chemotherapychemotherapy

• Bevacizumab (Avastin) was approved by Bevacizumab (Avastin) was approved by the U.S. Food and Drug Administration the U.S. Food and Drug Administration (FDA) in 2004 for the treatment of stage IV (FDA) in 2004 for the treatment of stage IV colorectal cancercolorectal cancer

Future Research

• You may have heard that taking aspirin prevents colon cancer. This is an exciting area of research, and studies are currently underway to evaluate whether aspirin can prevent the recurrence of precancerous colon polyps.

Follow-Up CareFollow-Up Care

• Doctor’s visitsDoctor’s visits

• Serial carcinoembryonic antigen (CEA) Serial carcinoembryonic antigen (CEA) measurements are recommendedmeasurements are recommended

• Colonoscopy one year after removal of Colonoscopy one year after removal of colorectal cancercolorectal cancer

• Surveillance colonoscopy every three to five Surveillance colonoscopy every three to five years to identify new polyps and/or cancersyears to identify new polyps and/or cancers