2010-04-23 18:07:15 UTC

Stopping Colorectal Cancer Screening after Age 75 Is Good for Patients

April 23, 2010

Theodore R. Levin, MD

Theodore R. Levin, MD

Staff Gastroenterologist, Gastroenterology Department, Kaiser Permanente Medical Center, Walnut Creek, CA  


The U.S. Preventive Service Task Force (USPSTF) recommends that patients who have been screened regularly for colorectal cancer (CRC) stop screening after the age of 75.1 Those who are past the age of 85 should not continue screening, regardless of prior screening.1 Can gastroenterologists confidently follow this recommendation and not risk harming their patients through under screening? Based on what is known about adenoma incidence, the risk of complications of screening and the number of expected life years to be gained through screening, following the USPSTF guideline is in patients’ best interests. Failing to stop screening exposes patients to the risk of screening with little possibility of benefit.

Adenoma incidence plateaus after age 50

A key part of any CRC screening strategy is the prevention of cancer through detection and removal of adenomas by polypectomy. If patients continued to form adenomas after the colon had been adequately screened, it would provide a rationale for continuing to screen for CRC as people age. Wendy Atkin proposed a once-only sigmoidoscopy screening trial for the U.K. based on her observation that while distal cancer prevalence increases with age, the prevalence of distal colorectal adenomas plateaus after the age of 50.2 This plateau suggests that new adenomas do not form after the age of 50 (figure 1). The sigmoid-oscopy series results for distal colonic adenomas were confirmed in an autopsy series from Johns Hopkins Hospital.3 Although the incidence of CRC increases with age (http://www.seer.cancer.gov/), the plateau in colorectal adenoma prevalence suggests that new adenomas are not forming among older patients. The adenomas found between the ages of 50 and 60 are very likely all the adenomas patients will ever form. High-quality screening should detect most of these adenomas and continuing screening beyond age 75 confers only risk of complications, with modest benefits.

Risk of complications

The risks of colonoscopy in general are low, with one to two serious GI events occurring per 1,000 procedures.4 However, the risk of adverse events continues to increase as patients age beyond 65 years (figure 2).4 This risk is particularly true for cardiovascular events such as congestive heart failure exacerbations, hypotension and syncope. In the decision to screen for CRC, physicians need to balance the benefits and harms of screening.1 As patients age past 75, the risk of harm begins to outweigh the benefits of screening, especially for patients who have already been screened and have been effectively cleared of their adenomas. They have little to gain from additional screening and have much to lose in terms of serious gastrointestinal events or cardiovascular complications of colonoscopy.

Life years gained through screening

In the absence of a randomized trial, simulation modeling is a useful way to evaluate several screening strategies simultaneously. The Cancer Intervention and Surveillance Modeling Network (CISNET) is a National Cancer Institute-sponsored consortium of micro-simulation models of CRC screening (http://cisnet.cancer.gov/ modeling). The 2008 USPSTF guideline was supported by two CISNET consortium models: MISCAN and the SimCRC.5 Both models found that continuing screening past the age of 75 required more than 400 additional colonoscopies per 1,000 persons, but added only between two and six life years gained per 1,000 persons.5 The efficiency ratio, or number of colonoscopies needed per additional life years gained, does not favor continuing to screen for CRC beyond age 75.

Another way of thinking about stopping screening is in terms of the amount of time until the benefits of screening will be realized, or the “pay-off time.”6 The typical time to benefit from a CRC screening test may range from five to 10 years. If a patient’s life expectancy is less than that, then they should not be exposed to the risks of screening.

My practice

In my own practice, I find it useful to discuss rationally with patients of all ages the benefits and risks of CRC screening. For each patient, the risk-benefit calculation will be somewhat different. While I don’t make hard and fast rules refusing to screen patients older than 75 for CRC, I do put the expected benefits in perspective relative to the other medical and personal issues for each patient, allowing them to make an informed choice. Most patients older than 75 are relieved to be told they do not need a routine screening colonoscopy, particularly if they have been screened previously. In settings where organized, outreach-based CRC screening programs are in place, it is reasonable to not conduct routine outreach for patients older than 75, based on what we know about risks and benefits. Individual patients and physicians can elect to continue screening, but the data suggests there will be little benefit for the majority of patients in continuing to screen beyond age 75.


  1. U.S. Preventive Services Task Force. Screening for Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med 2008 November 4, 2008;149(9):627-637.
  2. Atkin WS, Cuzick J, Northover JM, Whynes DK. Prevention of colorectal cancer by once-only sigmoidoscopy. Lancet 1993 Mar 20;341(8847):736-740.
  3. Pendergrass CJ, Edelstein DL, Hylind LM, Phillips BT, Iacobuzio-Donahue C, Romans K, et al. Occurrence of colorectal adenomas in younger adults: an epidemiologic necropsy study. Clin Gastroenterol Hepatol 2008 Sep;6(9):1011-1015.
  4. Warren JL, Klabunde CN, Mariotto AB, Meekins A, Topor M, Brown ML, et al. Adverse events after outpatient colonoscopy in the Medicare population. Ann Intern Med 2009 Jun 16;150(12):849-57, W152.
  5. Zauber AG, Lansdorp-Vogelaar I, Knudsen AB, Wilschut J, van Ballegooijen M, Kuntz KM. Evaluating test strategies for colorectal cancer screening: a decision analysis for the U.S. Preventive Services Task Force. Ann Intern Med 2008 Nov 4;149(9):659-69.
  6. Braithwaite RS, Fiellin D, Justice AC. The payoff time: a flexible framework to help clinicians decide when patients with comorbid disease are not likely to benefit from practice guidelines. Med Care 2009 Jun;47(6):610-617.

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