What is colon cancer?
Colon cancer is cancer of the large intestine (colon), the lower part of your digestive system. Rectal cancer is cancer of the last several inches of the colon. Together, they’re often referred to as colorectal cancers.
Most cases of colon cancer begin as small, noncancerous (benign) clumps of cells called adenomatous polyps. Over time some of these polyps become colon cancers.
How common is colon cancer?
Please discuss with your doctor for further information.
What are the symptoms of colon cancer?
The common symptoms of colon cancer are:
- A change in your bowel habits, including diarrhea or constipation or a change in the consistency of your stool, that lasts longer than four weeks
- Rectal bleeding or blood in your stool
- Persistent abdominal discomfort, such as cramps, gas or pain
- A feeling that your bowel doesn’t empty completely
- Weakness or fatigue
- Unexplained weight loss
Many people with colon cancer experience no symptoms in the early stages of the disease. When symptoms appear, they’ll likely vary, depending on the cancer’s size and location in your large intestine.
There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.
When should I see my doctor?
If you have any signs or symptoms listed above or have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.
What causes colon cancer?
In most cases, it’s not clear what causes colon cancer. Doctors know that colon cancer occurs when healthy cells in the colon develop errors in their DNA.
Healthy cells grow and divide in an orderly way to keep your body functioning normally. But when a cell’s DNA is damaged and becomes cancerous, cells continue to divide — even when new cells aren’t needed. As the cells accumulate, they form a tumor.
With time, the cancer cells can grow to invade and destroy normal tissue nearby. And cancerous cells can travel to other parts of the body.
Inherited gene mutations that increase the risk of colon cancer
Inherited gene mutations that increase the risk of colon cancer can be passed through families, but these inherited genes are linked to only a small percentage of colon cancers. Inherited gene mutations don’t make cancer inevitable, but they can increase an individual’s risk of cancer significantly.
The most common forms of inherited colon cancer syndromes are:
- Hereditary nonpolyposis colorectal cancer (HNPCC). HNPCC, also called Lynch syndrome, increases the risk of colon cancer and other cancers. People with HNPCC tend to develop colon cancer before age 50.
- Familial adenomatous polyposis (FAP). FAP is a rare disorder that causes you to develop thousands of polyps in the lining of your colon and rectum. People with untreated FAP have a greatly increased risk of developing colon cancer before age 40.
FAP, HNPCC and other, rarer inherited colon cancer syndromes can be detected through genetic testing. If you’re concerned about your family’s history of colon cancer, talk to your doctor about whether your family history suggests you have a risk of these conditions.
Association between diet and increased colon cancer risk
Studies of large groups of people have shown an association between a typical Western diet and an increased risk of colon cancer. A typical Western diet is high in fat and low in fiber.
When people move from areas where the typical diet is low in fat and high in fiber to areas where the typical Western diet is most common, the risk of colon cancer in these people increases significantly. It’s not clear why this occurs, but researchers are studying whether a high-fat, low-fiber diet affects the microbes that live in the colon or causes underlying inflammation that may contribute to cancer risk. This is an area of active investigation and research is ongoing.
What increases my risk for colon cancer?
There are many risk factors for colon cancer, such as:
- Older age. The great majority of people diagnosed with colon cancer are older than 50. Colon cancer can occur in younger people, but it occurs much less frequently.
- African-American race. African-Americans have a greater risk of colon cancer than do people of other races.
- A personal history of colorectal cancer or polyps. If you’ve already had colon cancer or adenomatous polyps, you have a greater risk of colon cancer in the future.
- Inflammatory intestinal conditions. Chronic inflammatory diseases of the colon, such as ulcerative colitis and Crohn’s disease, can increase your risk of colon cancer.
- Inherited syndromes that increase colon cancer risk. Genetic syndromes passed through generations of your family can increase your risk of colon cancer. These syndromes include familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, which is also known as Lynch syndrome.
- Family history of colon cancer. You’re more likely to develop colon cancer if you have a parent, sibling or child with the disease. If more than one family member has colon cancer or rectal cancer, your risk is even greater.
- Low-fiber, high-fat diet. Colon cancer and rectal cancer may be associated with a diet low in fiber and high in fat and calories. Research in this area has had mixed results. Some studies have found an increased risk of colon cancer in people who eat diets high in red meat and processed meat.
- A sedentary lifestyle. If you’re inactive, you’re more likely to develop colon cancer. Getting regular physical activity may reduce your risk of colon cancer.
- People with diabetes and insulin resistance may have an increased risk of colon cancer.
- People who are obese have an increased risk of colon cancer and an increased risk of dying of colon cancer when compared with people considered normal weight.
- People who smoke may have an increased risk of colon cancer.
- Heavy use of alcohol may increase your risk of colon cancer.
- Radiation therapy for cancer. Radiation therapy directed at the abdomen to treat previous cancers may increase the risk of colon cancer.
Diagnosis & treatment
The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.
How is colon cancer diagnosed?
In order to diagnose colon cancer, physicians will request a complete physical exam as well as personal and family medical histories. Diagnoses are usually made after the physician conducts a colonoscopy or a barium enema x-ray.
A colonoscopy is a procedure where a long, flexible tube with a camera on one end is inserted into the rectum to inspect the inside of the colon. If polyps are found in the colon, they are removed and sent to a pathologist for biopsy – an examination under a microscope that is used to detect cancerous or precancerous cells.
A barium enema begins with the patient not eating or drinking several hours before the procedure. A liquid solution containing the element barium is then injected into the colon through the rectum. After the barium lines the large intestine, an X-ray of the colon and rectum is taken. The barium will appear white on the X-ray and tumors and polyps will appear as dark outlines.
If a colon cancer diagnosis is made after a biopsy, doctors will often order chest x-rays, ultrasounds, or CT scans of the lungs, liver, and abdomen to see how far the cancer has spread. It is also not uncommon for a doctor to test blood for CEA (carcinoembryonic antigen) – a substance produced by some cancer cells.
How is colon cancer treated?
Cancer treatment depends on the type of cancer, the stage of the cancer (how much it has spread), age, health status, and additional personal characteristics. There is no single treatment for cancer, but the most common options for colon cancer are surgery, chemotherapy, and radiation therapy.
Treatments seek to remove the cancer and/or relieve painful symptoms that the cancer is causing.
Surgery to remove part of or the entire colon is called colectomy. During colectomy, a surgeon will remove the part of the colon containing the cancer as well as the marginal area close to the cancer.
Also, nearby lymph nodes are also usually removed. Depending on the extent of the colectomy, the healthy portion of the colon will either be reattached to the rectum or attached to an opening in the wall of the abdomen called a stoma. This latter option is called a colostomy, and waste will exit the body through the stoma into a colostomy bag, instead of exiting through the rectum.
In addition to invasive surgeries like colectomy, doctors can remove some small, localized cancers using endoscopy.
Laparoscopic surgery (using several small incisions in the abdomen) may also be an option to remove larger polyps.
Palliative surgery might also be employed to relieve symptoms for cancers that are advanced or untreatable. This type of surgery will try to relieve blockage of the colon or to inhibit other conditions to relieve pain, bleeding, and other symptoms.
Chemotherapy utilizes chemicals that interfere with the cell division process – damaging proteins or DNA – so that cancer cells will become damaged and die. These treatments target any rapidly dividing cells (not necessarily just cancer cells), but normal cells can usually recover from any chemical-induced damage, while cancer cells cannot.
Chemotherapy is generally used to treat cancer that has spread or metastasized because the medicines travel throughout the entire body. Treatment occurs in cycles so the body has time to heal between doses. However, there are still common side effects such as hair loss, nausea, fatigue, and vomiting. Combination therapies often include multiple types of chemotherapy or chemotherapy combined with other treatment options.
One large-scale study has shown that daily low-dose aspirin improves the survival of patients with certain gastrointestinal cancers, such as colon cancer. While the mechanism is not well understood and aspirin’s role in prevention has not been well studied, this information provides another possible adjunctive treatment option.
Radiation treatment, also known as radiotherapy, destroys cancer by focusing high-energy rays on the cancer cells. This causes damage to the molecules that make up the cancer cells and leads them to die.
Radiotherapy uses high-energy gamma-rays that are emitted from metals such as radium or high-energy x-rays. Radiotherapy can be used as a standalone treatment to shrink a tumor or destroy cancer cells; it is also used in combination with other cancer treatments.
Radiation treatments are not often used for early stage colon cancers, but may be employed if early stage rectal cancer has penetrated the wall of the rectum or traveled to nearby lymph nodes.
Side effects of radiation therapy may include mild skin changes resembling sunburn or suntan, nausea, vomiting, diarrhea, and fatigue. Patients also tend to lose their appetites and have trouble maintaining weight, but most side effects subside a few weeks after completing treatment.
Lifestyle changes & home remedies
What are some lifestyle changes or home remedies that can help me manage colon cancer?
The following lifestyles and home remedies might help you cope with colon cancer:
- Know what to expect. Learn enough about your cancer to feel comfortable making treatment decisions.
- Ask your doctor to tell you the type and stage of your cancer, as well as your treatment options and their side effects. The more you know, the more confident you’ll be when it comes to making decisions about your own care. Look for information in your local library and on reliable websites.
- Keep friends and family close. Keeping your close relationships strong will help you deal with your cancer. Friends and family can provide the practical support you’ll need, such as helping take care of your house if you’re in the hospital. And they can serve as emotional support when you feel overwhelmed by cancer.
- Find someone to talk with. Find a good listener who is willing to listen to you talk about your hopes and fears. This may be a friend or family member. The concern and understanding of a counselor, medical social worker, clergy member or cancer support group also may be helpful.
- Ask your doctor about support groups in your area. Or check your phone book, library or a cancer organization, such as the National Cancer Institute or the American Cancer Society.
If you have any questions, please consult with your doctor to better understand the best solution for you.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: July 13, 2017 | Last Modified: July 13, 2017
Colon cancer. http://www.mayoclinic.org/diseases-conditions/colon-cancer/manage/ptc-20188388. Accessed July 13, 2017.
Colon Cancer: Causes, Symptoms, and Treatments. http://www.medicalnewstoday.com/articles/150496.php. Accessed July 13, 2017.