More than 95 percent of colorectal cancers are adenocarcinomas, cancers that start in cells forming the mucus-making glands that lubricate the colon and rectum. While we usually don’t know what causes colorectal cancer, there are several risk factors that increase your chance of getting the disease:
- Age—Most colorectal cancers are found in people over 50.
- Race or background—People who are either African American or Jewish with an Eastern European background are at a higher risk.
- Medical history—People with ulcerative colitis, Crohn’s disease, Type 2 diabetes, or previous cancers have higher risk of developing colorectal cancer.
- Family medical history—Close family members with colorectal cancer, as well as some conditions passed down through families, raise the risk.
- Lifestyle—The links between diet, weight and exercise and colorectal cancer risk are some of the strongest for any type of cancer. Some evidence suggests that colorectal cancer may be associated with a diet that is high in fat and calories and low in foods with fiber, such as whole grains, fruits, and vegetables.
If you do have any of these risk factors, talk to your doctor. Your doctor may be able to suggest ways to reduce your risk, especially lifestyle factors that you can change.
Following screening guidelines is important, because polyps and colorectal cancers might not cause any symptoms, especially in the beginning. But you should also watch out for possible warning signs:
- Change in bowel habits
- Unexplained diarrhea or constipation
- Unusually narrow stools
- Bloody stool or rectal bleeding
- Stomach issues: bloating, cramping, unusual fullness and/or frequent gas pain
- Unexplained weight loss or gain
Other conditions can cause these symptoms, too, so it’s important to see a doctor—particularly if the problems persist for more than two weeks. Colorectal cancers are much easier to treat if caught early.
Not all polyps can change into cancer. But screening can catch pre-cancerous polyps and colorectal cancers before they cause symptoms—an important tool for identifying problems early on, when your chance for successful treatment is much higher. The U.S. Preventive Services Task Force (USPSTF) recommends that you:
- Start screening once you turn 50 and continue to age 75 (people at higher risk may need to start sooner and get tested more frequently—talk to your doctor)
- Pick a schedule and one of the three screening methods:
- Yearly: High-Sensitivity fecal occult blood test (FOBT) to look for blood in your stool
- Every 5 Years: Flexible sigmoidoscopy to look inside your rectum and part of your colon (still need to do FOBT every 3 years)
- Or Every 10 Years: Colonoscopy to look inside your rectum and your entire colon, with biopsy and polyp removal possible
Your doctor may recommend follow-up tests for any abnormal results. Talk to your doctor about screening after age 75. We also offer help for those who can’t afford screening.
We understand that waiting for test results is difficult—we use the latest tools to get you a prompt and accurate diagnosis, so that we can create your individualized treatment plan as soon as possible.
Our doctors start by taking a complete medical history (including any symptoms) and conducting a thorough physical examination.
Other diagnostic tools include:
- Digital Rectal Exam (DRE): a lubricated, gloved finger is inserted into the rectum to feel for lumps or anything else unusual
- Biopsy: cells or tissue are removed and examined with a microscope
- Colonoscopy: a thin tube with a light and camera is inserted into the rectum, to look at the rectum and entire colon and possibly remove polyps or a biopsy sample
- Sigmoidoscopy: similar to a colonoscopy, but only looks at the rectum and the lower part of the colon
- Virtual Colonoscopy: uses CT (CAT) scans to create a digital map of the colon (also called colonography or CT colonography)
- Fecal Occult Blood Test: looks for microscopic amounts of blood in the stool
- Carcinoembryonic Antigen (CEA) Assay: looks for elevated amounts of a substance called CEA in the blood, a possible sign of cancer
- Barium Enema: a special liquid is swallowed before X-rays are taken (also called lower GI series)
If cancer is diagnosed, certain imaging tests can determine how far the cancer has advanced:
- CT (CAT) Scan
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For more information or to schedule an appointment with a GI cancer specialist, call our scheduling line:
Awards & Recognitions
The MedStar Georgetown University Hospital Lombardi Comprehensive Cancer Center is the only National Cancer Institute (NCI)-designated comprehensive cancer center in the Washington, D.C. region.