Colorectal cancer is the second-leading cancer killer in the United States—but it doesn’t have to be. Regular screening is key to detecting colorectal cancer early, when it is most treatable. Colorectal cancer can even be prevented from developing when abnormalities are detected and continue to be monitored by a doctor.
Cancer occurs when abnormal cells in your body begin multiplying too quickly, causing a lump of tissue known as a tumor.
The colon, also called the large intestine or large bowel, is a muscular tube that forms the last part of the digestive tract. It absorbs water and stores food waste. The colon is about 4-6 feet long. When cancer forms in the colon, it is called colon cancer.
The last six inches of your colon is called the rectum; cancer of the rectum is called rectal cancer. When talking about colon and rectal cancer together, it is called colorectal cancer.
How does colorectal cancer occur?
The colon and rectum have a lining composed of millions of cells. When these cells go through abnormal changes, colon polyps can develop. If left untreated, these colon polyps can turn into cancer. Removing polyps early may prevent cancer from ever forming.
Polyps are fleshy clumps of tissue that form on the lining of the colon or rectum. Small polyps are usually benign (not cancerous). However, over time, cells in a polyp can change and become cancerous. The larger a polyp grows, the more likely this is to happen. Also, certain types of polyps known as adenomatous polyps are considered premalignant. This means that they will almost always become cancerous if they’re not removed.
Colorectal cancers usually start when polyp cells begin growing abnormally. As a cancerous tumor grows, it may involve more and more of the colon or rectum. In time, cancer can also grow beyond the colon or rectum and spread to nearby organs or to glands called lymph nodes. The cells can also travel to other parts of the body. This is known as metastasis. The earlier a cancerous tumor is removed, the better chance of preventing its spread.
What are the symptoms of colorectal cancer?
Colorectal cancer can cause symptoms including:
- Rectal bleeding
- Dark-colored stools
- Blood in your stool
- Diarrhea or constipation that lasts for several days
- Narrow stools
- Abdominal cramps or pain
- Unintended weight loss
If you are having symptoms of colorectal cancer, it is important that you let your doctor know right away. Your doctor may order a colonoscopy or other tests to find the cause of your symptoms. Although colorectal cancer is usually quite serious by the time the symptoms are noticeable, these symptoms also can point to other less-serious conditions, such as hemorrhoids or anal fissures.
What are the risk factors for colorectal cancer?
Risk factors for colorectal cancer include:
- Being 45 years of age or older
- Having a family history or personal history of colorectal cancer or adenomatous polyps
- Having a personal history of colorectal polyps, Crohn’s disease, or ulcerative colitis
- Having a family history of multiple concurrent solid-tumor cancers
How is colorectal cancer treated?
Colorectal cancer is usually diagnosed during a colonoscopy, which is a test that allows your doctor to check your colon and rectum for signs of colorectal cancer or colon polyps. If your doctor finds colorectal cancer, he or she will work closely with you to develop a treatment plan that may include:
- Surgery to remove cancerous parts of the colon and rectum
- Chemotherapy, which uses medications that kill cancer cells throughout your body
- Radiation therapy, which uses targeted high-energy X-rays to kill cancer cells in a specific area of your body
How can I prevent colorectal cancer?
The best way to prevent colorectal cancer is to have a colonoscopy. If you are at high risk of developing colorectal cancer or if you are experiencing symptoms, your doctor may recommend having screenings starting at an earlier age.
If your doctor recommends that you have a colonoscopy, it’s important to schedule the exam as soon as possible. Waiting too long to have the exam could increase your risk of developing colorectal cancer or, if colon cancer is found, decrease your chances of survival.
If you are having symptoms of colorectal cancer or think you may be at high risk of developing the condition, don’t wait—contact your primary care provider to discuss what you should do.