Chapter 22. Colorectal Cancer Screening

Screening for colorectal cancer (CRC) can reduce disease-related morbidity and mortality. The existing evidence has led to the recommendation of CRC screening as a standard component of preventive health care.

General Considerations

CRC is the second leading cause of cancer death in the United States and Western Europe. The lifetime risk of CRC in the United States is approximately 6%. In 2010, it was estimated that 72,090 men and 70,480 women would be diagnosed and 51,370 individuals would die of CRC. However, overall disease survival has improved from 51.4% in the 1970s to 64.9% in early 2000. Increased knowledge about the pathogenesis, advances in medical and surgical care, and the increasing emphasis on CRC screening programs have contributed to these substantial gains.

CRC can be prevented through readily available screening. Prevention efforts rely on the long time interval required for a benign adenomatous polyp to progress into an invasive cancer. It is estimated that the adenoma to carcinoma sequence unfolds over a 7- to 10-year period. In addition, CRC-related deaths are preventable if the disease is detected early. When diagnosed early, the 5-year survival rate for CRC that is still confined to the primary site (localized stage) is approximately 90%. Conversely, the corresponding 5-year survival for patients with known distant metastases is only 10%. Unfortunately, only 39% of cancers are diagnosed at an early stage and up to 19% of patients have distant metastases.

Nevertheless, CRC screening is presently underutilized in the United States. Approximately half of the population is currently compliant with standard screening recommendations, despite the array of available choices. CRC screening lags far behind screening for other common malignancies, such as breast, cervical, and prostate cancer. According to recent results by the National Center for Health Statistics, only 54% of Americans aged 50 years or older had undergone any type of CRC screening and only 42% had undergone screening within the recommended time interval. At present, issues of sensitivity, specificity, and patient acceptance limit existing CRC screening methods. Several factors contribute to the lack of compliance with CRC screening, including inappropriate perception of risk (particularly if patients are asymptomatic and without a family history of CRC), dietary restrictions or burdensome cathartic preparations, the invasiveness of procedures, and perceived discomfort, pain, and embarrassment related to certain screening techniques.