The second leading cause of cancer deaths in the United States is colorectal cancer. Most of these deaths are preventable through appropriate screening. Colorectal cancer lends itself to screening because it is a common and serious disease; it has readily identifiable and slow-growing precursor lesions; once developed, it advances slowly through the various stages; and recommended screening tests are available. The American College of Gastroenterology (ACG) created an expert panel to develop recommendations for colorectal cancer screening. Rex and associates published these guidelines for screening average and high-risk persons.
Persons are defined as being at average risk for colorectal cancer if they are 50 years or older and have no risk factors for colorectal cancer other than age. The Agency for Healthcare Policy and Research (AHCPR), now the Agency for Healthcare Research and Quality (AHRQ), developed options for screening average-risk patients (see Table 1). Each of the options has risks and benefits that need to be considered when recommending the appropriate screening procedure.
The preferred screening strategy, according to the ACG, is a colonoscopy every 10 years in the average-risk patient. The ACG makes this recommendation based on the fact that using colonoscopy for screening improves the detection rate of precancerous and cancerous lesions. In addition, polyps discovered during the procedure can be removed. The 10-year interval between colonoscopies provides a better opportunity for compliance. The ACG recognizes that the increased use of colonoscopy could also result in additional complications but believes this risk to be low. Current studies show that this strategy is more cost effective than our current strategies for detecting breast and cervical cancer. The ACG also recognizes that reimbursement for screening colonoscopy is generally unavailable, but anticipates that this situation will change over the next few years.
In cases where resources, expertise or reimbursement for screening colonoscopy are not available, the ACG recommends flexible sigmoidoscopy every five years plus annual fecal occult blood tests. The five-year interval for flexible sigmoidoscopy is currently under review. The ACG maintains the five-year interval recommendation but anticipates the eventual expansion of these intervals.
The ACG also made recommendations for screening patients with familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. Table 2 lists the recommendations of the ACG for screening patients with a strong family history of colon cancer. Patients with a single first-degree relative with colorectal cancer diagnosed at 60 years or older are classified as having moderately increased risk. These persons should be screened initially at age 40.