Reviewed January 2012

This information should not be used to self-diagnose, or be used in place of a qualified physician’s care.

What causes it and who gets it?
Listed below are some of the known causes of this cancer. Not all of the risk factors below may cause this cancer, but they may be contributing factors.

• Diet may be a factor. Risk seems to increase with diets low in fibre, fruit and vegetables and high in meats and fats. Risk seems to decrease with diets high in fibre and low in fats and red meat / processed meat.
• What increases the risk of colon and rectal cancers:
• Polyps or adenomas in the colon may become malignant. Polyps should always be removed and tested to see if they contain cancer. Most polyps do not contain cancer, but if left in place may develop into cancer.
• One in a hundred patients has a family background of polyps.
• Familial polyposis (Gardner's Syndrome) is equally common in men and women. Children of an affected parent have a 50% chance of inheriting the syndrome.
• A family history of colorectal cancer increases risk. The number of relatives affected, and their age when their cancer was diagnosed are important in estimating risk. We have a Hereditary Cancer Program in B.C.
• People with inflammatory bowel disease (ulcerative colitis, Crohn’s disease) have an increased risk of developing colon cancer. This risk increases for patients who developed colitis at an early age.
• Use of alcohol, especially in men. (Two (2) or more drinks per day)
• Body fatness / abdominal fatness.
• Low physical activity levels.
• Rectal cancer can recur (come back) more often than colon cancer. Close follow-up is necessary for these patients, and improves the possibility of cure.
• Statistics
• BC
• Canada

Can I help to prevent it?

• What is known to reduce the risk of colon and rectal cancers:
• Physical activity – people with moderate to high levels of physical activity have a lower rate of colon and rectal cancers. The evidence of benefit is stronger for colon cancer than for rectal cancer.
• What might reduce the risk of colon and rectal cancers:
• Dietary fibre – eat foods high in fibre.
• Garlic – unprocessed, as food.
• Milk or calcium.
• If you choose to drink, limit intake of alcohol to less than 2 drinks per day for men, 1 drink per day for women.
• Reduce your intake of red meat and processed meat.
• Canada’s Food Guide http://www.hc-sc.gc.ca/fn-an/food-guide-aliment/index_e.html  
• Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective http://www.dietandcancerreport.org/
• People who are known to be at moderate or high risk should contact their physician to discuss a personalized screening schedule. See “Screening” below.

Screening for this cancer

• The BC Medical Association has developed provincial screening guidelines for colon cancer. The patient guideline is available, as well as the health professional guideline.
• In the general population, screening is recommended to start at age 50. All people aged 50-75 should receive both of these tests:
• annual digital rectal examination (DRE)
• fecal occult blood test (a test looking for blood hidden in the feces). Fecal occult blood tests can reduce mortality from colorectal cancer by 25% - 45%.
• The fecal occult blood test is a simple test performed by examining a stool (feces) sample for evidence of bleeding. Unfortunately it does have a high false positive rate for conditions other than cancer, such as; inflammation of the colon, peptic ulcer and hemorrhoids. Even the eating of rare meat or vigorous tooth brushing may produce a false positive result.
• If you can see blood in your stool, you do not need to do this test. This test is only to check for hidden blood. If you find blood in your stool, contact your doctor.
• Men and women at higher risk should have more frequent, more thorough examinations beginning at a younger age. The screening guidelines (above) will help you and your doctor decide on the best plan for you.

Signs and Symptoms

• A change in your bowel habits:
• bowel obstruction
• stool size change
• constipation
• diarrhea
• Blood in the stool, either apparent (visible) or occult (hidden).
• Lower abdominal pain or pelvic pain.
• If the tumour has spread, it may result in enlargement of the liver, abdominal bloating, pain in lower back or bladder symptoms such as urinary frequency or blood in the urine.
• One in twenty patients may develop sudden obstruction of the bowel or a perforation (tear).
• Anemia.
• Feeling very tired.
• Nausea or vomiting.
• Weight loss and weakness.

Diagnosis
This is a list of some or all of the tests used to diagnose this type of cancer. For more information on diagnostic tests, please see our Recommended Links, Diagnosis section.

• General physical examination, including a digital rectal examination.
• Routine lab and blood tests.
• Testing of stool sample (feces) for occult (hidden) blood. (also, see Screening above)
• Barium enema X-ray. A special liquid is inserted into the colon by enema, and then x-rays are taken.
• Sigmoidoscopy – doctors can examine the lowest 50 cm (20 inches) of the colon with a thin, lighted tube. They can also use this scope to grab tiny bits of suspicious looking tissue to put under the microscope.
• Colonoscopy - doctors can examine both the upper and lower colon with a thin, lighted tube. They can also use this scope to grab tiny bits of suspicious looking tissue to put under the microscope.
• Biopsy of colon or rectal tissue. A doctor removes a small portion of the colon or rectum to examine under a microscope. This is the most accurate test of all, but because it involves cutting the body, the other less invasive tests are usually done first.
• CT scan of abdomen and pelvis.
• Ultrasound of abdomen.

Types & Stages
Staging describes the extent of a cancer. The TNM classification system is used as the standard around the world. In general a lower number in each category means a better prognosis. The stage of the cancer is used to plan the treatment.

• T describes the site and size of the main tumour (primary);
• N describes involvement of lymph nodes;
• M relates to whether the cancer has spread (presence or absence of distant metastases).

• Most cases of bowel and rectal cancers are adenocarcinomas. Sometimes a lymphoma or melanoma, sarcoma or squamous cell carcinoma may be found.
• Cancer of the small intestine (not the colon or rectum) is different, as is anus cancer.
• Stages of Colon Cancer  

Treatment
Cancer therapies can be highly individualized – your treatment may differ from what is described below. Colon and rectal cancers are sometimes treated differently, so they are listed separately here.

Colon Cancer
Treatment options depend on where the tumour is in the colon, how big it is and if it has grown or spread outside of the original site.

Surgery

• Surgery is the best option for a cure. The main aim of surgery is to cut out the cancer with a wide border above and below the tumour, as well as the lymph nodes near to the tumour.
• If a cure is not possible, tumours should still be removed to prevent possible blockage of the bowel or bleeding.
• In most cases the bowel can be rejoined during surgery: this is called anastomosis. Anastomosis (connecting) is sometimes not possible for patients who have obstructing tumours in the left (descending) side of the colon. Instead, they receive a colostomy. A colostomy is an opening in the abdomen that allows stool to empty into a plastic pouch attached over the opening. Usually a colostomy is temporary and the bowel may be re-anastomosed at a later date.
• If the tumour comes back as a single spot of tumour found in the lung or liver, occasionally  it may be surgically removed.

Radiation

• Radiotherapy isn’t usually useful in colon cancer.
• Sometimes it is used to relieve symptoms when cure is not possible.

Chemotherapy

• Chemotherapy may be given after surgery for patients who are at higher risk of relapse (recurrence). There are various chemotherapy combinations that may be offered, depending on individual circumstances.

Rectal Cancer
Treatment options depend on where the tumour is in the rectum, how big it is and if it has grown or spread outside of the original site.

Surgery

• If the cancer is in the rectum, there are different kinds of surgery that may be performed. The type of surgery usually depends on how high up the rectum the cancer is located.
• Most rectal cancer surgeries will require creation of a temporary or permanent colostomy
• Colostomy - the surgeon may create an artificial anus on the abdominal wall by cutting the colon and bringing the ends out to the surface. A pouch is worn over the hole (a stoma) to collect the waste.
• Very low rectal tumours (near the outside of the body) may require removal of the entire rectum with a permanent colostomy.
• For operable rectal cancers, chemotherapy and radiation may assist in improving the chance for cure.
• Inoperable rectal tumours may be treated with radiation therapy or combined chemotherapy/radiation. 

Chemotherapy

• Chemotherapy is useful in rectal cancer. It may be given before or after surgery for patients who are at higher risk for recurrence.
• Chemotherapy can be given alone or combined with radiotherapy.

Radiation

• Radiation therapy may be given before or after surgery.
• Recurrent rectal cancer may be controlled with radiation and chemotherapy..

Followup after Treatment

• Guidelines for followup after treatment has ended have been developed by the BC Cancer Agency and are available on our website.
• You will be returned to the care of your family physician, and followup will happen regularly.
• Followup testing is based on your type of cancer and your individual circumstances.

Coping with Cancer

• BC Cancer Agency staff can help with quality of life issues for those living with or affected by cancer. This includes the physical, emotional, psychological and practical aspects of care. Each cancer experience is different, but in one way or another, many cancer patients share the same needs.
• The effects of cancer and its treatment can present unique challenges: from practical concerns like money and housing, to emotional concerns like anxiety and grief. If you need support with the practical and emotional impacts of cancer, or in managing symptoms and side effects you can use the information in Coping with Cancer to connect to these resources.

Search our library catalogue

• Automatically get a bibliography of books, videos and other items available through our library.

BC Cancer Agency Videos / Presentations
The BC Cancer Agency and BC Cancer Foundation host an educational forum on colorectal cancers every second year. Presentations available for viewing:

Title	Presenter	Length	Year
Colorectal Cancer 101	Dr. Howard Lim, Medical Oncologist	18:00	2011
Clinical Trials	Dr. Howard Lim, Medical Oncologist	16:44	2009
Colorectal Cancer Support Group	John Christopherson, Clinical Counsellor	16:07	2009
Diet & Colorectal Cancer	Cheri Cosby, Registered Dietician,	36:00	2011
Hereditary Colorectal Cancer	Dr. Linlea Armstrong, Clinical Geneticist	17:03	2009
Navigating the Emotional Roller-coaster After a Diagnosis of Cancer	Janie Brown, Executive Director, Callanish Society	20:00	2011
Patient Experience	Mamie Angus	22:00	2011
Screening & Surveillance	Dr. Jen Telford, Medical Director, ColonCheck Program	19:00	2011
Surgical Aspects of Colorectal Cancer	Dr. Manoj Raval, Surgeon	24:00	2011
What is Complementary Medicine (CAM)?	Dr. Lynda Balneaves, CAMEO Program	24:00	2011

Recommended Websites
The following websites have been chosen and evaluated by the BC Cancer Agency.

1.  NCI http://www.cancer.gov/ 
2.  CCS http://www.cancer.ca/ 
3.  ASCO http://www.cancer.net/Cancer/cancer.html 
4.  BC Cancer Agency Recommended Links http://www.bccancer.bc.ca/PPI/RecommendedLinks/typesofcancer/colorectal.htm

Can I help with research at BCCA?
BCCA cancer patients are very helpful when it comes to the fight against cancer. Here are a few ways that you can help.

• Clinical Trials – join our treatment-based research. Ask your oncologist if you qualify for a clinical trial.
• What are the pros and cons of joining a clinical trial?
• Tumour Tissue Bank – support our research by donating some of your cancer tissue.
• BC Cancer Foundation – support our research with a donation of money.

This information has been reviewed and approved by a member of the Gastrointestinal (GI) Tumour Group.