THINGS TO KNOW ABOUT COLORECTAL CANCER AND ASSOCIATED SCREENINGS:

Most colorectal cancers grow slowly and do not produce symptoms right away, so screening is important to find these tumors early, when removal and treatments are more likely to work.

If you develop colon cancer, several treatments are available, including surgery, radiation therapy and drug treatments, such as chemotherapy, targeted therapy and immunotherapy.

Who should get screened for colorectal cancer?

■ Screenings are recommended for anyone at average risk starting at age 45. Those at high risk or with a family history of these cancers may be asked to begin younger. The Colorectal Cancer Alliance suggests getting screened for the first time at age 40 or 10 years before the age of the youngest case in your immediate family.

What type of tests are available?

■ A colonoscopy is an in-office procedure in which a flexible fiber-optic instrument is inserted through the anus in order to examine the interior of the colon. Though the procedure can be done under anesthesia, it requires a one- or two-day preparation involving a limited diet and plenty of fluids.

■ A fecal occult blood test is a lab test used to check stool samples for hidden (occult) blood. There are several types of these tests, which require a sample of a bowel movement that is tested for blood or DNA markers. These tests can give false negative and false positive results and may result in the need for further testing. Occult blood in the stool may indicate colon cancer or polyps in the colon or rectum — though not all cancers or polyps bleed.

What are the symptoms of colorectal cancer?

■ Most colorectal cancers start as precancerous polyps, or abnormal growths in the colon or rectum, which may not cause symptoms. Not all polyps turn into cancer. Symptoms that may develop include:

■ A persistent change in your bowel habits, including diarrhea or constipation or a change in the consistency of your stool

■ Rectal bleeding or blood in your stool

■ Persistent abdominal discomfort, such as cramps, gas or pain

■ Unexplained weight loss