Colorectal cancer starts in the colon or the rectum. These cancers can also be referred to separately as colon cancer or rectal cancer, depending on where they start, though they have many aspects in common.
This type of cancer usually develops slowly over the course of a number of years, often beginning as a non-cancerous polyp on the inner lining of your colon or rectum. Polyps are usually benign, or not cancerous. If not removed, they can evolve into cancer but don’t always. It depends on the type of polyp.
- Adenomatous polyps (adenomas) are polyps that can change into cancer, and are referred to as pre-cancerous.
- Hyperplastic polyps and inflammatory polyps are usually not pre-cancerous.
Another kind of pre-cancerous condition is called dysplasia. Dysplasia is an area in the lining of the colon or rectum where the cells look abnormal (but not like true cancer cells) when viewed under a microscope. These cells can change into cancer over time. Dysplasia can also be seen in people who have had diseases such as ulcerative colitis or Crohn’s disease for many years. Both ulcerative colitis and Crohn’s disease cause chronic inflammation of the colon.
- Age: Most cases occur in people in their 60s and 70s. Cases before age 50 are relatively uncommon unless there is a family history of early colorectal cancer.
- Polyps: The presence of polyps in the colon increases risk, especially if they are large or if there are many of them.
- Personal history of colorectal cancer: If you’ve previously been diagnosed and treated for colorectal cancer you’re at higher risk for developing it again.
- Personal history of bowel disease: Inflammatory bowel diseases (including ulcerative colitis or Crohn’s colitis) increase your risk of colorectal cancer because they inflame the colon over extended periods of time.
- History of ovarian, uterine, or breast cancer: Women who have had any of these cancers are at higher risk.
- Race or ethnic background: African Americans and Jews of Eastern European descent are at higher risk
- Family history of colorectal cancer: Someone with a family history of the disease, especially in a parent or sibling before the age of 55 or multiple relatives at any age, is at a higher risk.
- Genetics: About 20 percent of colon cancer cases come because of specific genetic mutations. That’s why genetic testing is beneficial.
For patients who are concerned about inherited family syndromes that cause colon cancer, we offer advanced genetic testing to let you know your risk. Take the online assessment.
Avoid the following:
- A diet that is high in red, processed, or heavily cooked meats.
- Lack of exercise.
- Obesity, particularly having excess fat in the waist area, rather than the hips or thighs.
- Cigarette smoking: Studies indicate that smokers are 30 to 40 percent more likely than nonsmokers to die of colorectal cancer because they are more likely to develop polyps.
- Too much alcohol consumption.
Colorectal cancer prevention
There are other things you can do to help reduce your risk of developing colorectal cancers, including increasing the amount of vitamin D, calcium, magnesium and folic acid in your diet.
Aspirin and other NSAIDs
It is possible that aspirin or other non-steroidal anti-inflammatory drugs (NSAIDS) like ibuprofen, as well as some arthritis drugs, may lower the risk of colorectal cancer and polyps. Aspirin may even prevent the growth of polyps in people who were previously treated for early stages of colorectal cancer or who had previously had polyps removed from the colon. However, you should talk with us prior to beginning any NSAID remedy.
It is possible that hormone-replacement therapy (HRT) for women, which consists of estrogen and progesterone and is used after menopause, may also help reduce the risk of colorectal cancer. However, the decision to use HRT is one that should be made between you and your doctor after discussing the potential benefits and risks.
The National Cancer Institute provides current information about risks and benefits of postmenopausal hormone use on their website.
- Abnormal cells are found in the inner lining of the colon. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 also is called carcinoma in situ.
- Cancer has formed and spread into the first (submucosa) or second (muscle) layers of the rectal wall. It has not spread outside of the rectum.
- Cancer has spread outside of the rectal walls into the surrounding fat or nearby tissue. It has not gone into the lymph nodes. It is divided into stages: IIA, IIB or IIC depending on the extent of local tumor involvement.
- Cancer has spread to nearby lymph nodes. It has not spread to other parts of the body. It is divided into stages IIIA, IIIB or IIIC depending on the extent of local tumor involvement and the number of lymph nodes that contain cancer.
- Cancer has spread to other parts of the body, such as the liver, lungs or ovaries. It is divided into stages IVA, IVB and IVC depending on the number of different parts of the body to which the cancer has spread.
Treatment for colorectal cancer can vary depending on whether the tumor is located in the colon or rectum.Learn About Our Treatment Options