Depending on where colorectal cancer starts, it can be called colon cancer or rectal cancer and are often classified together because they have many features in common.
Colon Cancer & Rectal Cancer Symptoms
- Diarrhea, constipation, or narrow stools that last for more than a few days
- A feeling that you need to have a bowel movement that doesn’t go away after doing so
- Rectal bleeding, dark stools, or blood in the stool (often, though, the stool will look normal)
- Cramping or stomach pain
- Weakness and tiredness
Colon & Rectal Cancer Risk Factors
The most common factors for an increased risk of colon cancer or rectal cancer are:
- Age: Nine out of 10 people who develop colorectal cancer are older than 50. However, it’s important to note that the rate of colorectal cancer is rising among people who are under age 50, and the reason for this is unclear.
- Medical history: Having had polyps, colon cancer or rectal cancer before, a history of bowel disease, or a family history of colon cancer or rectal cancer.
- Racial and ethnic background: African-Americans and Ashkenazi Jews (those of Eastern European descent) have a higher risk for colon and rectal cancer.
- Lifestyle: Poor diet, lack of exercise, being overweight, smoking, alcohol, and diabetes appears to increase risk of developing colon and rectal cancer.
Colon & Rectal Cancer Diagnosis & Staging
If a routine screening finds something suspicious or if you are experiencing symptoms of colorectal cancer, there are a variety of tests your physician may order to determine a diagnosis of cancer and how advanced the cancer is (known as staging). Staging your cancer will be used in determining a treatment plan.
Diagnostic Tests for Colon Cancer
Diagnostic colonoscopy: During a diagnostic colonoscopy, your physician will examine the colon and rectum with a colonoscope, a thin, flexible tube with a tiny video camera on its end. It is inserted through the anus and into the rectum and the colon. During this procedure a biopsy may also be performed or suspicious-looking areas, such as polyps, could be removed if needed.
Diagnostic Tests for Rectal Cancer
Proctoscopy: During this procedure, your physician will insert a proctoscope through the anus to examine the rectum. A proctoscope is a thin, rigid tube with a tiny video camera on its end that allows the physician to look closely at the inside lining of the rectum and determine the size and location of the tumor.
Additional Tests for Colorectal Cancer
- Biopsy: Biopsies to confirm a colorectal cancer diagnosis usually occur during a colonoscopy, during which the physician removes a small piece of tissue to examine at the lab. At times a part of the colon may need to be surgically removed to make the diagnosis. If cancer is found, other tests may also be done on the biopsy samples to better classify the cancer and be used in your treatment plan.
- Blood tests: Your physician will likely order a number of blood tests, including a complete blood count (CBC) to determine whether you have anemia and a liver enzyme test because colorectal cancer sometimes spreads to the liver. Talk to your doctor about the different types of blood tests and how they are used in determining your treatment plan.
- Imaging tests: Imaging tests use sound waves, x-rays, magnetic fields, or radioactive substances to create pictures of the inside of your body, including computed tomography (CT or CAT) scan, ultrasound, and magnetic resonance imaging (MRI) scan. Imaging tests are done for a variety of reasons, including to at suspicious areas that might be cancer or to learn how far cancer might have spread.