The digestive system, also known as our gastrointestinal system, is the series of organs our bodies use to break down food, absorb nutrients, and excrete waste. Food proceeds from our mouth, down our esophagus, through the stomach, and from the small intestine to large intestine before excretion. The word “colorectal” refers to two parts of the large intestine: the colon and the rectum. This means “colorectal cancer” includes both cancer of the colon as well as that of the rectum.

The wall of the large intestine is made up of several layers of tissue. Colorectal cancer typically starts when cells of the innermost layer multiply uncontrollably and grow outward through the other layers. These other layers contain blood and lymphatic vessels. When cancer grows into these vessels, cancer may spread to other parts of the body.

Colorectal cancer develops as a result of changes to the genetic material within colorectal cells. These changes result in the pattern of cell growth and division characteristic of colorectal cancer. Although the increased likelihood of developing colorectal cancer is associated with the following factors, according to the American Cancer Society, in most cases, physicians and scientists are still trying to determine what causes colorectal cancer to develop:

• Aging
• Personal history of colorectal polyps
• Personal history of previous colorectal cancer
• Personal history of inflammatory bowel disease
• Family history of colorectal cancer
• Family history of adenomatous (glandular) polyps
• Certain genetic mutations
• Obesity
• Lack of physical activity
• Smoking
• Abuse and/or overconsumption of alcohol
• A diet rich in processed and/or red meats
• A diet rich in meat cooked at high temperatures

Detecting colorectal cancer begins with regular screening. “Screening” involves looking for cancer as well as any precancerous growths, such as polyps, in people who may seem healthy. A colorectal polyp is an abnormal growth of tissue on the inside lining of either the colon or rectum. Regular screening is important because it allows for the following:

Detection of colorectal cancer early, which enables more effective treatment and better patient outcomes
Prevention of colorectal cancer because doctors may find and remove any growths suspicious for precancerous activity
Increased likelihood of developing colorectal cancer is associated with increasing age. The American Cancer Society recommends men and women use at least one of the tests below, each followed by their recommended frequency of testing, to screen for cancer and/or polyps which could be precancerous:

Colonoscopy - every 10 years
CT colonography - every 5 years*
Flexible sigmoidoscopy - every 5 years*
Double-contrast barium enema - every 5 years*
Fecal immunochemical test (FIT) - every year*,**
Guaiac-based fecal occult blood test (gFOBT) - every year*,**
Stool DNA test - every 3 years*
*Colonoscopy recommended if these tests come back positive.
**High-sensitivity versions of these tests recommended for use at home using multiple samples.
People with a greater risk of colorectal cancer should decide with their doctor on a screening plan that is most appropriate for them.

The following may be indicative of colorectal cancer but may also be indicative of other illnesses:

• Blood in the stool, which may either appear bright red or darken the stool

• Abnormal weight loss

• Abdominal pain and/or discomfort

• Change in the frequency of bowel movements

• Constipation

• Cramping

• Diarrhea

• Fatigue

• Frequent bloating and/or gas pains

• Nausea and vomiting

• Rectal bleeding

• Sensation to have a bowel movement that persists even after having one

• Weakness

It is important you tell your doctor if you have any of these signs and symptoms, so he or she may determine their cause and plan treatment, if necessary.

“Staging” occurs when a physician uses to test and scan results to determine which parts of the body are involved by cancer, in this case, colorectal cancer. Staging is important because different stages of colorectal cancer are better addressed with treatments that may differ in amount, combination, or type. According to the American Joint Committee on Cancer (AJCC), the stages for colorectal cancer are as follows:

Stage 0

This stage is the earliest stage of colorectal cancer development; cancer has not grown beyond the innermost lining of either the colon or rectum.

Stage I

This stage describes colorectal cancer that has grown through the innermost lining of the colon or rectum but has not spread to nearby lymph nodes or more distant parts of the body.

Stages II & III

Cancer has spread and may involve more of the surrounding tissue, may involve nearby lymph nodes, or may have spread to both surrounding lymph nodes and other nearby parts of the body.

Stage IV

In this stage, cancer has spread to parts of the body distant from where it began, such as different organ systems. These systems might include the bones, distant lymph nodes, liver, or lungs.

Treatment of colorectal cancer, depending on the stage and type, may include chemotherapy, radiation therapy, and/or surgery. These treatments may be used individually or in combination based on your doctor’s recommendations. It’s important to discuss all of your treatment options with your doctor to help make the decision that best fits your needs. Some important factors to consider when deciding on a colorectal cancer treatment plan include

• Your age, health, and lifestyle.
• The stage of your cancer.
• Any other serious health conditions you have.
• Your feelings about the need to treat the cancer right away.
• Your doctor’s opinion about if you need to treat the cancer right away.
• The likelihood that treatment will help fight or cure your cancer.
• Possible side effects from each treatment method.

You may feel the need to make a quick decision, but it is very important to ask questions if there is anything about which you’re not entirely sure. It is very important for you and your doctor to communicate and work together to weigh the benefits of each treatment option against the possible adverse effects in order to ultimately determine which treatment option is best for you.