Colorectal cancer occurs when the cells in the colon or rectum grow and multiply uncontrollably, damaging surrounding tissue and interfering with the normal function of the colon or rectum. Colorectal cancer is the third most common cancer diagnosed in the United States. When colon and rectal cancers are found early, there is nearly a 90% chance for cure!
In most cases, colorectal cancers develop slowly over many years. Most cancers start as a polyp—a growth of tissue that starts in the lining and grows into the center of the colon or rectum. This tissue may or may not be a cancer. An adenoma is a type of polyp that can become a cancer. Removing a polyp early may keep it from becoming a cancer.
The colon and rectum are parts of the body’s digestive system, which removes nutrients from food and stores waste until it passes out of the body. Together, the colon and rectum form a long, muscular tube called the large intestine. The colon is the first six feet of the large intestine and the rectum is the last 8-10 inches. Cancer that begins in the colon is called colon cancer and cancer that begins in the rectum is called rectal cancer. Cancers affecting either of these organs also is called colorectal cancer.
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Many factors may influence the development of colorectal cancer, including:
- Age: Colorectal cancer is most common in people over the age of 50.
- Family History: Your risk is higher with a family history (especially parent and/or sibling) of colorectal cancer or adenomatous polyps.
- Personal History: Your risk is higher with a personal history of inflammatory bowel disease such as Crohn’s disease or ulcerative colitis, colorectal cancer or adenomatous polyps.
- Race or Ethnic Background: Some racial and ethnic groups such as African American or people of Eastern European Jewish descent (Ashkenazi Jews) have a higher colorectal cancer risk.
- Weight: Lack of physical activity and obesity are risk factors.
- Diet: A high-fat diet, particularly animal fats, may increase your risk. Diets high in fruits and vegetables are thought to decrease your risk.
- Cigarette Smoking and Alcohol: Your risk may be higher if you smoke or drink alcohol.
You can take action to reduce your risk of developing Colorectal Cancer by:
- Eating at least five servings of fruits and vegetables per day
- Limiting your fat intake to no more than 30% of your total daily calories
- Exercising regularly
- Maintaining your ideal weight
- Quitting smoking
- Limiting alcohol consumption
Cancer screenings are medical tests that are performed when a person has no symptoms. Starting at age 50, men and women should follow one of the five examination schedules below. All positive tests (FOBT, FIT, flexible sigmoidoscopy, barium enema) should be followed up with a colonoscopy.
- Colonoscopy: Recommended every 10 years. A colonoscopy is a longer version of sigmoidoscopy and examines the entire colon
- Fecal Occult Blood Test (FOBT): Recommended every year. This test is available in take-home versions. FOBT is a stool sample which is examined for traces of blood not visible to the naked eye.
- Fecal Immunochemical Test (FIT): FIT is a take-home test that detects blood proteins in stool. A small, long handled brush is used to collect a stool sample, which is placed on a test card and sent to a lab for examination.
- Flexible Sigmoidoscopy: Recommended every five years. A tiny camera with flexible tubing is inserted into the rectum, providing a view of the rectum and the lower colon. This procedure can be used to remove suspicious tissue for examination.
- Double-Contrast Barium enema: Recommended every five years. Barium is a chemical that allows the bowel lining to be visualized on an x-ray. A barium solution is administered by enema then a series of x-rays are taken.
People at moderate or high risk for colorectal cancer (e.g., strong family history) should talk with their doctor about the need for a different testing schedule.
These screening guidelines are provided as a guide. If results of these exams suggest cancer, more extensive diagnostic tests of the colon or rectum should be conducted. More frequent exams are needed if polyps (precancerous lesions) are found. In individuals at increased risk with a family history of colorectal cancer or polyps or a personal history of inflammatory bowel disease, screening may need to begin earlier.
Early stage colorectal cancer may have no symptoms. As stated previously, most colorectal cancers begin as a polyp, a non-cancerous growth on the colon wall that can grow larger and become cancerous. As a polyp grows, they can bleed or obstruct the intestine. Symptoms of colorectal cancer are:
- Rectal bleeding
- Blood in the stool or after a bowel movement
- Prolonged diarrhea
- A change in size or shape of stool
- Abdominal pain or a cramping pain in your lower stomach
- A feeling of discomfort or urge to have a bowel movement
If you are having any of these symptoms, please contact your health care provider.
There are many methods of diagnosing colorectal cancer. Some of the procedures are the same as covered under the screening guidelines. Below are some additional tools used.
- Digital Rectal Examination (DRE): The doctor inserts a gloved finger into the rectum to feel for polyps or other irregularities.
- Carinoembryonic Antigen (CEA): A blood test that determines the presence of CEA, a substance or tumor marker produced by some cancerous tumors. This test can also be used to measure tumor growth or assess if cancer has recurred after treatment.
- Endorectal Ultrasound: An ultrasound probe is inserted into the rectum. The probe sends sound waves that people cannot hear. The waves bounce off the rectum and nearby tissue and a computer uses echoes to create a picture. The picture can show how deep a rectal tumor has grown or whether the cancer has spread to lymph nodes or nearby tissue.
- Chest X-Ray: X-rays of your chest may show whether cancer has spread to the lungs.
- CT Scans: An x-ray machine linked to a computer that takes a series of detailed pictures of areas inside your body. An injection of a dye may be required for some scans. A CT scan may show whether cancer has spread to the liver, lungs or other organs.
Staging determines the extent of the cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.
- Stage 0: Abnormal cells are found in the innermost lining of the colon or rectum. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in-situ.
- Stage I: Cancer has formed and spread beyond the innermost tissue layer of the colon or rectum to the middle layers. Stage I colorectal cancer is sometimes called Dukes A colorectal cancer.
- Stage II: Colorectal cancer is divided into Stage IIA and IIB. Stage II is sometimes called Dukes B colorectal cancer.
- Stage IIA: Cancer has spread beyond the middle tissue layers of the colon or rectal wall or has spread to nearby tissues around the colon or rectum.
- Stage IIB: Cancer has spread beyond the colon or rectum wall into nearby organs and/or through abdominal cavity.
- Stage III: Colorectal cancer is divided into stage IIIA, stage IIIB and stage IIIC. Stage III is sometimes called Dukes C colorectal cancer.
- Stage IIIA: Cancer has spread from the innermost tissue layer of the colon or rectum wall to the middle layers and has spread to as many as three lymph nodes
- Stage IIIB: Cancer has spread to as many as three nearby lymph nodes and has spread:
- beyond the middle tissue layers of the colon or rectum wall
- to nearby tissues around the colon or rectum wall
- beyond the colon or rectum wall into nearby organs and/or through the abdominal cavity
- Stage IIIC: Cancer has spread to four or more nearby lymph nodes and has spread:
- to or beyond the middle tissue layers of the colon or rectum wall
- to nearby tissue around the colon or rectum
- to nearby organs and/or through abdominal cavity
- Stage IV: Cancer may have spread to nearby lymph nodes and has spread to other parts of the body, such as the liver or lungs. Stage IV colorectal cancer is sometimes called Dukes D colorectal cancer.
There are four main types of treatment for colorectal cancers. Depending on the stage of the cancer, two or more types of treatment maybe used at the same time or used one after the other.
Side Effects of Treatment
- Surgery: Surgery is the most common treatment for colon and rectal cancers. Depending on the stage and location of the tumor, different surgical methods are used.
- Local Excision: If the tumors are small enough, they may be removable through minimally invasive surgery. Tiny excisions are made in the abdomen and a miniature camera and surgical instruments are inserted. The surgeon uses computer imaging to locate and remove the tumor.
- Polypectomy: Suspicious or cancerous polyps on the colon wall can easily be removed. A colonoscope is a long tube with a camera on the end. The colonscope is inserted into the rectum then guided to the area requiring treatment and a tiny scissor-like instrument removes the polyp.
- Colectomy: Surgeons remove the cancerous portion of the colon, along with a margin of healthy tissue on either side, and then join the colon back together. This procedure is also called a hemicolectomy or segmental resection.
- Resection and Colostomy: If the colon cannot be joined after removing the cancer, surgeons will perform a colostomy. A stoma (hole) is cut in the abdominal wall and attached to a segment of colon. Bodily wastes go through the stoma into a plastic bag outside the body. Colostomies may be temporary, allowing the bowel to heal before resection. However, about 15% of colostomies are permanent.
- Radiation Therapy: Radiation therapy maybe used to destroy any colon or rectal cancer cells that remain after surgery. Radiation is used most often in rectal cancers, or those that cannot be treated with surgery. It can also be used to relieve cancer symptoms.
- Chemotherapy: Chemotherapy can be used to shrink tumors before surgery or to lengthen the survivor time after surgery.
- Targeted Therapy: Researchers are developing new drugs that are designed to seek out and destroy specific types of cancer cells without affecting healthy cells. Man-made proteins called monoclonal antibodies have been approved for use, along with chemotherapy, to treat colorectal cancer.
- Clinical Trials: These research studies help evaluate new ways to treat cancer. In some studies, patients may receive a new treatment or compare promising new treatment vs. standard therapy.
The side effects of cancer treatment depend on the type of treatment and may differ for each person. Most often the side effects are temporary. Patients should report any side effects to their doctors. Doctors and nurses can suggest ways to help relieve symptoms.
After Treatment is Completed
- Surgery: Causes short term pain and tenderness in the area of the operation. Surgery for colorectal cancer may also cause temporary constipation or diarrhea. Patient who have a colostomy may have irritation of the skin around the stoma. The doctor, nurse, or enterstomal therapist can teach the patient how to clean the area and prevent irritation and infection.
- Chemotherapy: Affects normal as well as cancer cells. Side effects depend largely on the specific drugs and dose (amount of drug given). Common side effects of chemotherapy include nausea, vomiting, hair loss, mouth sores, diarrhea and fatigue.
- Radiation Therapy: Like chemotherapy, radiation therapy affects normal as well as cancer cells. Side effects of radiation therapy depend mainly on the treatment dose and part of the body being treated. Common side effects of radiation therapy are fatigue, skin changes at the site where the treatment is given, loss of appetite, nausea, and diarrhea. Sometimes radiation therapy can cause bleeding through the rectum (bloody stools).
- Biological Therapy: The side effects may vary depending on the specific type of treatment that is received. Often, treatments cause flu-like symptoms, such as chills, fever, weakness and nausea.
Finishing treatment can be exciting, but it can also be stressful because you may be worried that the cancer could come back (this is called recurrence). These are very common concerns among many that have had a cancer diagnosis.
- Follow-up Care: It is very important to keep all follow-up appointments during treatment and after treatment is completed. The doctor may ask about symptoms, perform a physical exam and may order blood work or imaging test. Follow-up care is needed to check for cancer recurrence or spread, as well as evaluate side effects from the treatment. This is a good time to ask questions or discuss any concerns you may have with your health care team. Some side effects may last a few weeks to several months, but there are others that can be permanent. Discuss this with your doctor.
- Physical Examinations: The doctor will recommend the frequency of getting a physical examination usually every 3-6 months for the first two years after treatment, then every six months or so for the next few years.
- Colonscopy: In most cases, your doctor will recommend a colonscopy within a year after surgery.
- Imaging Studies: The doctor may or may not recommend image studies, depending on the stage of the cancer and other factors.
- Tumor Markers (Blood Test): Carcinoembryonic antigen (CEA) and CA 19-9 are substances found in the blood of some people with colorectal cancer. Tests for one or both of these substances are sometimes useful if you have symptoms that suggest that the cancer may have come back. Many doctors order these tests every 3 to 6 months to detect a recurrence before you have symptoms. If tumor marker levels start to rise, colonoscopy or imaging tests may be done to try to locate a recurrence.
- For Patients with a Colostomy: If you have a colostomy, you may feel worried or isolated from normal activities. Whether your colostomy is temporary or permanent, an enterostomal therapist can teach you about the care of your colostomy.