What is colorectal cancer?
Colorectal cancer occurs when cells in the body's colon or rectum grow abnormally. The colon and rectum are parts of the body's digestive system, which turns food into energy and gets rid of solid waste.
Colon cancer is another term used for cancer that starts in the colon, and rectal or rectum cancer are other names for cancer that starts in the rectum.
Cancer that starts in the colon or rectum and then travels into the liver or elsewhere in the body is said to have metastasized. But it's still called colorectal cancer because it started in the colon or rectum.
Colon cancers usually grow slowly and take many years to develop from small growths (polyps) inside the colon.
Causes of colorectal cancer
Like other cancers, colorectal cancer start with healthy cells that mutate and divide too often, forming into a lump or mass called a tumor. Over time, these cells can spread to other parts of the body as well.
Risk factors for colorectal cancer
Risk factors for colon or rectal cancer can include:
- Smoking
- Being obese
- Not exercising enough
- Eating a lot of red meat
- Being African American
- Being 50 years old or older
- Having a personal or family history of polyps
- Having Type 2 diabetes that's not well-controlled
- Having a disease that involves swelling of the colon or rectum
- Drinking three or more alcoholic beverages per week on a regular basis
Symptoms of colorectal cancer
Signs of this cancer can include:
- Bleeding or pain when you push out stool
- Dark or red blood or mucus in your stool
- Stomach-area cramps, pain or gas that doesn't go away
- Diarrhea or constipation that lasts four weeks or longer
- Changes in your bowel movements, such as narrow stools
- Fatigue, weakness or weight loss that's not due to other reasons
Diagnosis of colorectal cancer
To discover this type of cancer, your doctor will ask you about your health and habits, do a physical exam and perform tests.
These tests might include:
- Hemoccult test — an at-home test kit used to detect blood in your stool that may not be visible to the naked eye
- Colonoscopy — an endoscopic exam, during which a long, flexible tube is inserted into the rectum to allows your doctor to view the inside of the colon, and if needed, remove polyps or abnormal tissue.
- CT scan — this test combines multiple x-ray pictures to create a 3-D image that shows more than a single x-ray does.
- Ultrasound — this test involves pressing a small wand against the body that uses sound waves to create pictures of the body's insides.
- MRI — this test uses magnetic fields to create pictures of the inside of the body.
- Biopsy — for this test, the doctor collects a small sample of tissue from the colon or rectum, typically during a colonoscopy, that is examined in a lab.
Treatments for colorectal cancer
The main treatment options include surgery, radiation, chemotherapy and targeted therapy. All of these treatments involve side effects that you should discuss with your doctor.
Surgery
Surgery is a common treatment for colon cancer. It involves removing the cancerous part of the colon, plus small nearby areas of healthy tissue and sometimes the lymph nodes in the area as well. If the cancer is small and close to the anus, surgeons can sometimes remove it through the anus.
For some colon cancers, the doctor creates an opening on the patient’s side to allow for solid waste to leave the body. This opening is called a colostomy. A colostomy may be temporary or permanent.
Radiation
This treatment uses rays to destroy cancer cells. It also may provide symptom relief.
Chemotherapy
Chemotherapy is given on a schedule with multiple doses and often involves two or more types of drugs.
Treatments can be used individually or combined prior to surgery or after, depending on the stage and size.
Targeted drugs
Targeted drugs are meant to attack specific cells and spare healthy cells. Often side effects from these drugs are less severe than traditional chemotherapy.
Recovery from colorectal cancer
After you complete your treatment, you should continue to visit your doctor for follow-up exams, blood tests and possibly other tests as well. These visits should occur every few months at first and then could become less frequent, such as once a year.