Clinical Geriatrics

Introduction
Colorectal cancer (CRC) is the third most common type of cancer and second leading cause of cancer death in the United States.¹ It primarily affects patients over 50 years of age. While the much publicized death of news anchor Katie Couric’s 42-year-old husband Jay Monahan spawned national interest in CRC screening,² screening rates in this country remain at only approximately 50%.

Colorectal cancer almost always develops from precursor polyps. Further, colonoscopy with polypectomy can reduce the incidence of this largely preventable cancer by approximately 66%.^3,4 In addition to background information about CRC, this article will provide an update on approaches to screening older adults, including:

• Identifying your patients at increased risk for CRC

• New insights on the utility of screening tests

• When to consider to stop screening for CRC

• Surveillance of patients at increased risk

• Virtual colonoscopy, fecal DNA, and the future direction of screening for CRC

Epidemiology of Colorectal Cancer
Colorectal cancer affects women and men equally, with a lifetime risk estimated to be approximately 5-6%. Most cases of incident cancer will arise from adenomatous polyps in a process involving polyp growth and a series of genetic mutations.⁵ Screening for CRC can be successful in part due to the estimated 5-10 years it usually requires for malignant transformation.⁶ Providers for older adults can confidently tell patients that choosing to be screened reduces the number of new cases detected and deaths from CRC. This benefit stems from the early detection and removal of polyps, as well as the detection of asymptomatic, early-stage cancer.^7-9

New cases of CRC begin to rise steadily after age 50, which is the basis for several major association recommendations to begin screening older adults at this point in time^10-12 (Figure).¹³, the importance of awareness of screening options will continue to increase for providers to older adults. Geriatricians will also increasingly see patients with a history of polyps and will need to carefully review polyp surveillance recommendations for those patients.

Who Is at Risk and Who Should Be Screened?
Specific patients at increased risk should be targeted for screening. Those patients at risk for CRC earlier in life include those with such familial syndromes as familial adenomatous polyposis and hereditary nonpolyposis colon cancer (not discussed in this article). Patients with symptoms or signs of CRC (ie, anemia, iron deficiency, blood in stool, change in bowel habits, unexplained abdominal pain, or weight loss) should be referred for diagnostic colonoscopy and fall outside the realm of screening.

Given the relatively high baseline frequency of disease and that CRC is a leading cause of cancer death in the United States, all patients over age 50 years should be considered to be at risk and considered for screening. Providers should give options to patients for CRC screening and acknowledge advantages and disadvantages to the various approaches. With the variable sensitivity of available tests, low frequency of screening overall, access and patient compliance issues, any screening is better than no screening at all.

Screening should begin for men and women around age 50 years for those at average risk.