Colon 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. Colon cancer is the third most common cancer diagnosed in the United States. Most colon cancers (about 70%) are found in the first six feet of the large intestine. The other 30% occur in the last 10 inches of the large intestine (rectum). Collectively they are referred to as colorectal cancers.
One in 19 Americans will be diagnosed with colon cancer in their lifetime, for an overall risk of 5.4%. Although colon cancer affects men and women equally, rectal cancer is more common in men. When colon and rectal cancers are found early, there is nearly a 90% chance for cure.
About 80% of colon cancer cases are sporadic, meaning that cause is nonspecific or undetermined. The other 20% of colon cancers are hereditary. People who have a first-degree family member with colon cancer are more likely to be affected themselves. About 5% of this group has a predisposition to hereditary non-polyposis colorectal cancer (Lynch syndrome), a rare disease that generally strikes people aged 30 to 50.
There often are no symptoms of colon cancer in its early stages. Most colon cancers begin as a polyp, a small non-cancerous growth on the colon wall that can grow larger and become cancerous. As polyps grow, they can bleed or obstruct the intestine.
Many colon symptoms are not cancer, but if you notice one or more of these symptoms for more than two weeks, see your doctor.
Many factors may influence the development of colon cancer, including:
Age: Colon cancer is most common in people over 50.
Family history: Your risk is higher with a family history (especially parent, sibling) of colon cancer or adenomatous polyps.
Personal history: Your risk is higher with a personal history of inflammatory bowel disease (Crohn’s disease or colitis), colon cancer or adenomatous polyps.
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.
Reducing Your Risk
You can take action to reduce your risk of developing colon cancer by:
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.
People at moderate or high risk for colon 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 colon cancer or polyps or a personal history of inflammatory bowel disease, screening may need to begin earlier.
There are many methods for diagnosing colon cancer. Some of these procedures are also used as screening devices to detect colon cancers in the early stages, when treatment is more successful.
Fecal Occult Blood Test (FOBT): A stool sample is examined for traces of blood not visible to the naked eye. If you do see blood in your stool, contact your doctor immediately.
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.
Sigmoidoscopy: A tiny camera with flexible plastic tubing is inserted into the rectum, providing a view of the rectum and lower colon. This procedure can also be used to remove suspicious tissue for examination.
Colonoscopy: A colonoscope is a longer version of a sigmoidoscope, and can examine the entire colon. Patients must be sedated for a colonoscopy.
Virtual colonoscopy: Instead of a scope, physicians use imaging technology to view the colon. Air is pumped into the colon to expand it for better imaging. Virtual colonoscopy can be performed with computed tomography (CT) or magnetic resonance imaging (MRI).
Double Contrast Barium Enema (DCBE): Barium is a chemical that allows the bowel lining to show up on X-ray. A barium solution is administered by enema; then the patient undergoes a series of X-rays.
Digital Rectal Exam: The doctor inserts a gloved finger into the rectum to feel for polyps or other irregularities.
Carcinoembryonic 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.
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 wall to the middle layers. Stage I colon cancer is sometimes called Dukes A colon cancer.
Stage II: Colon cancer is divided into stage IIA and stage IIB. Stage II colon cancer is sometimes called Dukes B colon cancer.
Stage IIA: Cancer has spread beyond the middle tissue layers of the colon or rectum 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 the peritoneum
Stage III: Colon cancer is divided into stage IIIA, stage IIIB and stage IIIC. Stage III colon cancer is sometimes called Dukes C colon 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:
Stage IIIC: Cancer has spread to four or more nearby lymph nodes and has spread:
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 colon cancer is sometimes called Dukes D colon cancer.
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 tumors are small enough, they may be removed with minimally invasive surgery. Tiny incisions are made in the abdomen. 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 in the end. The colonoscope is inserted in the rectum and 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 & colostomy: If the colon cannot be rejoined 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 waste goes 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 may be used to destroy any colon or rectal cancer cells that remain after surgery. Radiation is used most often on rectal cancers, or those that cannot be treated with surgery. It can also be used to relieve cancer symptoms.
Chemotherapy can be used to shrink rectal tumors before surgery, or to lengthen survival time after surgery. Chemotherapy is generally not effective for advanced or recurring colon cancers.
Researchers are developing new drugs that are designed to seek out and destroy specific types of cancer cells without affecting healthy cells. Drugs such as Avastin, Erbitux and Vectibix are showing promise in treating colon cancer.
Cancer is a journey that no one needs to take alone. There are many forms of support to help you through every stage: diagnosis, treatment and survivorship. Whether you meet with other cancer survivors like yourself, use complementary therapies or individual coping mechanisms, support is available. Listed below are just some of the ways to find help and hope.
Getting together with other cancer patients in a support group is a valuable coping tool. Support groups are usually focused on a single disease or topic, such as breast cancer survivors or people coping with life-changing side effects from their cancer or cancer therapy. These groups allow participants to meet others like themselves and seek strength from each other. Most major cities and cancer hospitals offer support groups that meet weekly or monthly. There are also dozens of online support Web sites or message boards for those who may not have access to a traditional meeting.
Complementary therapies are used in conjunction with cancer treatment, in an effort to reduce treatment side effects, ease depression and anxiety and help cancer patients take their mind off the negative aspects of their situation. Complementary therapies may include mind-body exercises like yoga, Tai Chi and Qi gong; visualization or guided imagery; using art or music as therapy and self-expression and traditional Eastern medicine such as acupuncture.
Staying physically active as much as possible during cancer treatment has many positive benefits. Physical activity stimulates the release of endorphins, a hormone that helps elevate mood, as well as decreasing feelings of fatigue.
Exercises for cancer patients can range from simple stretches done in the bed or chair, to more active pursuits such as walking or light gardening work. However, it’s important not to push yourself too hard. Check with your doctor before attempting any physical activity to make sure you are up to it.
Many people find it helpful to keep a journal of their cancer treatment experience. It may be as simple as recording symptoms and side effects into a notebook, or may include personal emotions and opinions about what they may be going through. Journals can be private, like a diary, or shared with loved ones and even strangers.
Increasingly, people are turning to the Internet to share their cancer journey with the world at large and to seek out others with similar experiences. Many cancer patients have begun their own Web log, or “blog” to publicize their battle with cancer. Twitter, a mini-blogging technology that limits posts to 140 characters, has also proven to be a helpful tool for cancer patients to keep friends updated and reach out to others.