What is colorectal cancer?
Colorectal cancer starts in the colon or the rectum (the largest part of the intestine located near the anus). Because they share common features, these two cancers are often referred to as colorectal cancer. Cancers start when cells in your body grow quickly in an abnormal way.
When colorectal cancer is discovered early, it’s usually treatable and not life threatening. However, it can lead to death if found too late to be treated.
Symptoms of colorectal cancer
The primary symptom of colorectal cancer is a polyp (growth) in the lining of your colon or rectum. If you have one, you may not even know. Polyps can only be seen with a special camera during a colonoscopy. Some polyps aren’t harmful, but some can become cancerous.
Once a polyp develops, it may lead to the following symptoms:
- Bleeding from your rectum.
- Blood in your stool or in the toilet after you have a bowel movement.
- Changes in the shape or consistency of your stool (diarrhea or constipation lasting several weeks).
- Stomach cramps.
- Stomach discomfort, such has the urge to have a bowel movement when you don’t really need to have one.
- Weakness or fatigue.
- Unplanned weight loss.
Other medical conditions can cause these same symptoms. See your doctor right away to find what’s causing your symptoms.
What causes colorectal cancer?
There are several things that can increase your risk for colorectal cancer. These include:
- Age (especially over 50).
- Ethnicity, especially African Americans and Jews of Eastern European.
- Prior history of polyps.
- Family history of colorectal cancer.
- Inflammatory Bowel Disease (IBD), including ulcerative colitis and Crohn’s disease.
- Inherited genetic syndromes (Lynch syndrome, Peutz-Jeghers syndrome).
- Poor diet, specifically a low-fiber, high-fat diet.
- Lack of exercise.
- Type 2 diabetes.
- Excessive alcohol.
- Previous radiation treatment for cancer.
After age 50, doctors recommend you undergo screening every five to 10 years. If you fall into one of the groups above, you may need to be tested more often.
How is colorectal cancer diagnosed?
Colorectal cancer is diagnosed through several methods.
Routine screening tests can find polyps or cancers before they’re large enough to cause symptoms. This is when the cancer can be more effectively treated.
If you have symptoms, your doctor will perform a digital rectal exam. In this exam, your doctor will put his or her gloved finger into your rectum to feel for growths. It’s not painful. However, it can be uncomfortable. Additional tests might include:
- Barium enema. For this test, you are given an enema (fluid injected into the rectum). The liquid contains a dye that makes your colon show up on an X-ray. Your doctor looks at the X-ray to find abnormal spots in your entire colon. If he or she finds one or detects polyps, your doctor will probably order a colonoscopy.
- Fecal occult blood test. This test checks your stool for blood that you can’t see. Your doctor gives you a test kit and instructions to use it at home. Then, you return a stool sample to your doctor for testing. If the lab finds blood, another test is done to look for a polyp, cancer, or another cause of bleeding.
- Stool DNA test. This test checks your stool for cells that are shed by colon cancers or precancerous polyps. If your test is positive, your doctor will probably want you to have a colonoscopy.
- Colonoscopy. This test involves inserting a thin, flexible tube into your rectum. The tube is connected to a small video camera that can see your entire colon. The tube also can be used to remove polyps and cancers during the exam. Before you have this test, you are given a medicine to make you sleepy. A colonoscopy may be uncomfortable. It’s usually not painful.
- Virtual colonoscopy. This new test uses a computerized tomography (CT) machine to take pictures of your colon. Your doctor can then see all of the images combined in a computer to check for polyps or cancer. If your doctor finds polyps or other abnormalities, you will need to have a traditional colonoscopy for further testing or to remove them.
- Flexible sigmoidoscopy. In this test, your doctor puts a thin, flexible tube with a light on the end into your rectum. The tube is connected to a tiny video camera so the doctor can look at the rectum and the lower part of your colon. This test can be done in your doctor’s office. It lets your doctor see polyps when they are very small (before they can be found with a fecal occult blood test). Flexible sigmoidoscopy may miss cancerous polyps that are in the upper part of the colon. Therefore, some doctors prefer a colonoscopy. Your doctor will discuss options with you.
If you’ve been diagnosed with colorectal cancer, your cancer will be given a stage. Cancer stages include stage I, stage II, stage III, and stage IV. Stage IV is considered advanced cancer. Stage I cancers offer more hope in a successful outcome after treatment.
The American Academy of Family Physicians (AAFP) recommends screening for colorectal cancer with fecal tests, flexible sigmoidoscopy, or colonoscopy (tests used to diagnose colorectal cancer) starting at age 50 and continuing until age 75 years.
For adults between the ages of 76 and 85, the AAFP recommends that the decision to screen for colorectal cancer be an individual one. Your doctor will offer advice based on your overall health and prior screening history. The AAFP recommends against screening for colorectal cancer in adults older than 85 years.
Can colorectal cancer be prevented or avoided?
Colorectal cancer can’t be prevented or avoided. However, you can reduce your risk by choosing a healthy diet and exercising. Also, lose weight, quit smoking, and reduce the amount of alcohol you drink. Genetics tests can tell you if you carry an inherited gene that increases your risk of colorectal cancer. Discuss this option with your doctor, including the costs.
Colorectal cancer treatment
If you have colorectal cancer, your doctor will talk to you about treatment options. These include:
- Surgery. This is usually the main treatment for colon and rectal cancer. It removes the tumor.
- Chemotherapy. This is treatment with drugs that kill cancer cells that may have been left behind after a tumor is removed by surgery. It’s often used when there is a risk the colon or rectal cancer will come back. Chemotherapy is usually combined with another treatment called immunotherapy. During immunotherapy, a person takes drugs that help the immune system fight cancer. Research has shown the combination of chemotherapy and immunotherapy is better than chemotherapy alone. Sometimes chemotherapy can be used before surgery to shrink the size of a tumor.
- Radiotherapy. Also known as radiation, this treatment uses high-power X-rays to kill cancer cells. Radiation therapy can be used in many ways. Radiation may be used either before or after surgery for rectal cancer. It can also be combined with chemotherapy after surgery. A combination of chemotherapy and radiation have been shown to improve the outcome in rectal cancer treatment. Sometimes, radiation is given before surgery for rectal cancer to shrink the tumor and prevent return of the cancer in that area. If you have stage II or III colorectal cancer, the risk of cancer coming back is significant. There’s a risk the cancer may come back in your pelvic area. Your doctor will likely recommend radiation and surgery since radiation reduces this risk.
- Targeted therapy. These are drugs that attack the type of cancer cells you have. This treatment is used for advanced colon cancer.
Cancer treatment affects people differently. Some people have few or no side effects. However, many people feel very sick.
Talk to your doctor about clinical trials available to people with colorectal cancer. Clinical trials offer new research-based treatments that may or may not be effective. People enrolled in clinical trials must qualify for the trial.
Living with colorectal cancer
Living with colorectal cancer can cause fear and discomfort, depending on the stage of your cancer. If you were treated successfully and are cancer free, you’ll be required to have regular screenings the rest of your life.
Questions to ask your doctor
- Is it too late to successfully beat colorectal cancer if I see blood in my stool?
- If I have surgery to remove all or part of my colon, will I have to have a colostomy bag?
- What is the recurrence rate for colorectal cancer caught and treated early?
- What are other reasons for blood in my stool?
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.