CE/CME

Colorectal Cancer Screening: What’s Accurate and Cost-Effective?

Clinician Reviews. 2013 November;23(11):38-44

References

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Because colorectal cancer is often asymptomatic, routine screening is essential to detect lesions at an early stage. The evolution of health care has brought new and improved screening methods for colorectal cancer, including CT colonography. This article weighs the pros and cons of the available screening methods used to detect colorectal cancer in the general population today.

Colorectal cancer (CRC) is the second-leading cause of death from cancer in Europe and the United States and the third most commonly diagnosed cancer in both men and women in the US.^1-5 According to the American Cancer Society, 102,480 new cases of colon cancer and 40,340 new cases of rectal cancer will be diagnosed in 2013.⁵ Although screening rates remain low and the incidence of new CRC diagnoses rises annually, mortality rates are decreasing, most likely due to screening and improved treatment.⁵

CLINICAL PRESENTATION OF COLORECTAL CANCER
CRC is often asymptomatic until it reaches an advanced stage. At this point, symptoms include weight loss, night sweats, fever, loss of appetite, blood in the stool, pencil-shaped stools, diarrhea, constipation, anemia, and/or dizzy spells.^6,7 On abdominal exam, a clinician may note dullness to percussion over the right or left lower quadrant, palpate a mass in the right or left lower quadrant, and/or elicit tenderness or guarding upon deep palpation. The clinician may be inclined to do a fecal occult blood test (FOBT) to confirm active GI bleeding.^1,3

CURRENT SCREENING RECOMMENDATIONS
The US Preventive Services Task Force (USPSTF) currently recommends that screening for CRC—with FOBT, sigmoidoscopy, or colonoscopy—start at age 50 and continue through age 75.⁸ For patients whose first-degree relative has a history of CRC, initial screening should start at age 40.

It is recommended that people ages 76 to 85 make personalized, informed screening decisions in conjunction with their medical provider. Patients ages 85 or older should not be screened for CRC because of the estimated five-year time frame between the detection of cancer and the onset of symptoms or death. In the unlikely circumstance that the patient is screened and a lesion is found, the patient would not benefit but most likely experience harm from treatment efforts; however, this should be decided on a case-by-case basis.⁸

CONSIDERATIONS IN SCREENING THE ELDERLY
Much of the data on older populations are outdated, and thus more research needs to be conducted in this population. However, data from two studies dating from 2006 provide tools to help clinicians decide if screening in the older population is beneficial.

One study of the benefit of screening for CRC in the older population stated that clinicians must assess both the burden of chronic illness and the patient’s age as part of their evaluation. This study concluded that, because of the risks and costs that are associated with CRC screening, it is important to identify only those individuals who are likely to benefit from screening, rather than screening the elderly population in general.⁹

Another study examined the benefit of screening colonoscopy in two elderly groups (ages 75 to 79 and age ≥ 80) versus younger patients (ages 50 to 54; the control group). It was found that

• Screening in the older population may increase the risk for perforation and respiratory depression secondary to sedation,

• Screening may take longer to complete, and

• Screening may be challenging with less successful bowel preparation.¹⁰

Further, the prevalence of neoplasia was lowest in the control group (13.8%) compared to the 75-to-79-year-old (26.5%) and oldest (≥ 80; 28.6%) groups. The mean extension of life expectancy was much lower in the oldest group, compared to the control group (0.13 years versus 0.85 years), which represents a 6.5-fold difference. These results suggest that the benefit of colonoscopy screening in elderly persons ages 76 and older results in smaller gains in life expectancy and does not outweigh the risks. This test, therefore, should only be used when the patient expresses a preference for colonoscopy and the clinician feels it will significantly benefit the patient.¹⁰

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