What is Colon Cancer?
Colon cancer starts in the colon. Most colon cancers develop slowly over many years. A large number of colon cancer cases begin as a polyp—a growth of tissue that starts in the lining and grows into the center of the colon. This tissue may or may not be colon cancer. A polyp known as adenoma can become colon cancer. Removing a polyp early may keep it from becoming colon cancer.
What is Rectal Cancer?
Rectal cancer is cancer that starts in the tissues of the rectum.
Risk Assessment & Symptoms for Colon Cancer and Rectal Cancer
Increased risk for colon cancer and rectal cancer has been linked to:
Age—Nine out of 10 people with colorectal cancer are older than 50.
History—Having had polyps, colon cancer or rectal cancer before, a history of bowel disease, or a family history of colon cancer or rectal cancer.
Race—African Americans and Jews of Eastern European descent have a higher risk for colon and rectal cancer.
Lifestyle—Poor diet, lack of exercise, being overweight, smoking, alcohol, and diabetes appears to increase risk of developing colon and rectal cancer.
Although colon and rectal cancer, also referred to as colorectal cancer, often display no symptoms (which is why early screening is so important), in later stages people may experience:
- Diarrhea, constipation, or narrow stools that last for more than a few days.
- A feeling that you need to have a bowel movement that doesn’t go away after doing so.
- Rectal bleeding, dark stools, or blood in the stool (often, though, the stool will look normal).
- Cramping or stomach pain.
- Weakness and tiredness.
Colon Cancer and Rectal Cancer Screenings
Colon and rectal cancer remain a leading cause of cancer-related mortality in the United States—causing nearly 50,000 deaths a year. This is most likely due to the fact that 40 percent of those who should get screened for colon cancer and rectal cancer don’t—usually due to fear or embarrassment.
The American Cancer Society, American College of Radiology, and U.S. Multi-Society Task Force on Colorectal Cancer recommend regular screenings beginning at age 50 for people at average risk for colon cancer or rectal cancer. Several screening options exist. Your family doctor can help determine what colon cancer or rectal screening cancer program is right for you.
Fecal occult blood tests typically are performed at home and returned to a laboratory for analysis. If blood (occult) is detected in the stool samples, further testing will be required.
Colonoscopy examines the rectum and entire 6-foot length of the colon (large intestine). Patients prepare by eating a restricted diet and drinking a laxative preparation to ensure the colon is free of feces. Patients are sedated for the procedure, during which the doctor threads a thin, flexible endoscope with a miniature camera on the leading end through the rectum and into the colon. Images from inside the colon are viewed on a display monitor. It takes about 30 minutes. If precancerous polyps or other abnormal tissue are found, they can be removed during the exam.
Sigmoidoscopy examines only the rectum and lower two feet of the colon. It takes about 10-20 minutes. Sedation is optional. Preparation for the test is easier than for a colonoscopy. However, 50 percent of polyps and cancers are found in the upper colon, which is beyond the reach of most sigmoidoscopes.
Double-contrast barium enemas evaluate the colon using X-ray and barium contrast dye to view a clear silhouette of the rectum, colon, and sometimes, a small portion of the small intestine. If polyps are detected, a colonoscopy will probably be recommended.
The best time to be screened for colon or rectal cancer is when you’re feeling well and not having symptoms. Because when detected early, colon and rectal cancer are not only treatable, but also preventable.
Source for portions of this information: National Cancer Institute