Colorectal Cancer: Screening and Surveillance Recommendations

CRC screening can reduce mortality through the detection of early-stage disease and the detection and removal of ademomatous polyps [11]. Increasing access to and utilization of CRC screening tests is likely to lead to improvements in mortality reduction, as only about half of people aged 50 or older report having received CRC testing consistent with current guidelines [1].

Case Study

Initial Presentation

A 55-year-old white male presents for a routine visit and asks about colon cancer screening. His father was diagnosed with colon cancer at the age of 78. Overall, he feels well and does not have any particular complaints. His bowel habits are normal and he denies melena and hematochezia. His past medical history is significant for diabetes, hypertension, and obesity. He was a previous smoker and has a few alcoholic drinks on the weekends. His physical exam is unremarkable. Results of recent blood work are normal and there is no evidence of anemia.

• What are this patient’s risk factors for developing colon cancer?

Risk Factors for CRC

There are numerous factors that are thought to influence risk for CRC. Nonmodifiable risk factors include a personal or family history of CRC or adenomatous polyps, and a personal history of chronic inflammatory bowel disease. Modifiable risk factors that have been associated with an increased risk of CRC in epidemiologic studies include physical inactivity, obesity, high consumption of red or processed meats, smoking, and moderate-to-heavy alcohol consumption. In fact, a prospective study showed that up to 23% of colorectal cancers were considered to be potentially avoidable by adhering to multiple healthy lifestyle recommendations including maintaining a healthy weight, being physically active at least 30 minutes per day, eating a healthy diet, and avoiding smoking and drinking excessive amounts of alcohol [12].

People with a first-degree relative (parent, sibling, or offspring) who has had CRC have 2 to 3 times the risk of developing the disease compared with individuals with no family history; if the relative was diagnosed at a young age or if there is more than 1 affected relative, risk increases to 3 to 6 times that of the general population [13,14]. About 5% of patients with CRC have a well-defined genetic syndrome that causes the disease [15]. The most common of these is Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer or HNPCC), which accounts for 2% to 4% of all CRC cases [16]. Although individuals with Lynch syndrome are predisposed to numerous types of cancer, risk of CRC is highest. A recent study of CRC in 147 Lynch syndrome families in the United States found lifetime risk of CRC to be 66% in men and 43% in women, with a median age at diagnosis of 42 years and 47 years, respectively [17]. Familial adenomatous polyposis (FAP) is the second most common predisposing genetic syndrome; for these individuals, the lifetime risk of CRC approaches 100% without intervention (eg, colectomy) [16].

People who have inflammatory bowel disease of the colon (both ulcerative colitis and Crohn’s disease) have an increased risk of developing CRC that correlates with the extent and the duration of the inflammation [18]. It is estimated that 18% of patients with a 30-year history of ulcerative colitis will develop CRC [19]. In addition, several studies have found an association between diabetes and increased risk of CRC [20,21]. Though adult-onset type 2 diabetes (the most common type) and CRC share similar risk factors, including physical inactivity and obesity, a positive association between diabetes and CRC has been found even after accounting for physical activity, body mass index, and waist circumference [22].