Lower Gastrointestinal Conditions: Colorectal Cancer Screening and Prevention.

Colorectal cancer (CRC) is the third most commonly diagnosed malignancy and the second most common cause of cancer mortality worldwide. It was estimated that approximately 50,630 mortalities due to CRC would occur in the United States in 2018. Seventy percent of CRC originates from adenomatous polyps that become dysplastic over time. Risk factors for CRC include genetic syndromes, such as familial polyposis syndromes and Lynch syndrome; inflammatory bowel disease; dietary and lifestyle factors; and family history of advanced adenomas. The U.S. Preventive Services Task Force and the U.S. Multi-Society Task Force on CRC recommend screening beginning at age 50 years for patients at average risk. Multiple screening tools may be offered based on availability and patient comorbid conditions, personal preferences, and risk factors. In the United States, colonoscopy continues to be the screening modality of choice but is not without risks and adverse effects. Currently, genetic testing has no role in the screening of patients at average risk. Research into CRC prevention is ongoing but there currently are no recommended strategies other than adequate screening.