Surprisingly it may not be colonoscopy but fecal occult blood testing (FOBT).

A computer model has found annual home testing with a  fecal occult  blood test, either Hemoccult II® or Hemoccult SENSA®,  is more cost-effective than colonoscopy every 10 years to screen people of average risk for colorectal cancer.

The model compared the number of life years saved under several scenarios of costs and  compliance with annual testing and follow-up colonoscopies after positive guaiac tests.  For the same fixed budget, more people could be screened with an FOBT and more life years saved.

Organized state and federal screening programs are faced with a complex task of choosing the right test that will get the most people screened effectively at the lowest cost.  In addition to the cost of the test, program planners have to consider how many patients will follow up with repeat fecal occult list blood testing every year and how many will actually get a colonoscopy if they have a positive test.

Best case scenario: With 100 percent compliance with screening recommendations and follow-up testing, a budget of $1 million dollars would result in a total of 50.9, 52.8, and 40.9 additional life-years for the population of individuals screened with Hemoccult II, Hemoccult SENSA, and colonoscopy, respectively.

The average lifetime cost per person is $1,399 for Hemoccult II, $1,656 for Hemoccult SENSA, and $2,110 for colonoscopy as the primary screening method.  Costs included colonoscopy follow-up when tests are positive.

In computing costs, a cost of $23 for FOBT and $699 for colonoscopy was used.

Other scenarios:

A program using Hemoccult II, with a screening compliance of 60 percent or higher, will yield more total life-years gained than a program using colonoscopy with 100 percent compliance.  Hemoccult II will perform better than colonoscopy if at least 75 percent of those with positive guaiac-based fecal occult blood tests undergo diagnostic follow-up colonoscopies.

Only at the lowest level of compliance with testing and follow-up  is colonoscopy more effective for broad public screening programs.

Health economist Sujha Subramanian and her team at RTI International concluded,

Although colonoscopy is currently emerging as the most frequently performed colorectal cancer screening test in the United States, in many instances it might not be the optimal choice, especially for programs with fixed budgets. Across a broad population, as opposed to for use in a particular individual, the Hemoccult SENSA test can result in more benefit than colonoscopy. Therefore, colonoscopy should not be automatically considered the appropriate choice.

SOURCE: Subramanian et al.,Health Affairs, published online July 29, 2010.  The entire article is available online.

What Does This Mean for Individuals?

This study was designed to look at public screening programs with fixed budgets, not make recommendations for individuals.

Your screening choice, as an individual, may be different.

Colonoscopy allows both screening and removal of any polyps that are found during the procedure.  Per test, it is more sensitive for cancer and polyps than FOBT, but may not find all polyps. For average risk patients, it only needs to be repeated every 10 years unless polyps are discovered.

FOBT requires careful compliance to an annual screening schedule and faithful follow-up of all positive tests with a colonoscopy.

People with extra risk because of family or personal history of colorectal cancer or polyps or patients with ulcerative colitis or Crohn’s disease need to be screened with colonoscopy and more often.

Discuss the right test for you with your doctor!

Three out of four primary care doctors did a fecal occult blood test once during an office visit, a method that is ineffective in finding cancer or preventing death from colorectal cancer. One out of four used the in-office test exclusively.

Less than half of doctors had a system in place to be sure that home tests were completed and returned. 

What Primary Care Doctors are Doing

The 2006–2007 National Survey of Primary Care Physicians Recommendations and Practices for Cancer Screening conducted by the National Cancer Institute in collaboration with CDC and the Agency for Healthcare Research and Quality surveyed a sample of primary care doctors about their recommendations for colorectal cancer screening.  Family physicians, general practitioners,obstetrician-gynecologists, and internists were included.

Over ninety percent of surveyed doctors said that they used an FOBT for colorectal screening at least once a month.  Of those 24.8 percent performed the test only in their offices, 52.9 percent used both office and home tests.  Three out of five doctors used a test that is no longer recommended because of its low sensitivity.

A single in-office test during a rectal exam will miss 95 percent of cancers and advanced polyps.

In other practices that reduced the value of fecal occult blood tests:

• Almost 1 in 5 doctors (17.8 percent) repeated a positive FOBT rather than refer a patient for colonoscopy immediately.
• Of those doctors who repeated FOBT, nearly a third (28.8  percent) stopped follow-up evaluation if the second FOBT was negative.
• Most doctors (61.1 percent) were using the least sensitive test, a standard guaiac test, which is no longer recommended.  Only 22 percent used the higher sensitivity guaiac test and 8.9 percent used a fecal immunohistochemical test which is more sensitive and doesn’t require patients to follow a special diet or refrain from certain medications before the test. 14.7 percent didn’t know what test they used.
• Only 44.3 percent had a system in place — chart reminders, telephone calls, or mailings — to follow up on FOBTs that weren’t returned.
• 62.2 percent of doctors had no system in place to be sure that patients referred for follow-up evaluation of a positive test actually got that testing.

Writing in the Journal of General Internal Medicine, CDC scientist Marion Nadel PhD and her team said,

While FOBT done appropriately is an important screening option, in-office FOBT may be worse than no screening at all because it misses 95% of cases of advanced neoplasia, giving many patients a false sense of reassurance.

The researchers concluded,

Although FOBT is an important option for colorectal cancer screening, our study suggests that its potential to save lives is not currently being realized because many physicians are continuing to use inappropriate implementation methods. Intensified efforts to inform physicians of recommended technique and promote the use of systems for tracking test completion and follow-up are needed.

What the Recommendations Are

Both the American Cancer Society and the US Preventive Services Task Force have fecal occult blood testing as a colorectal cancer screening option.

Early Detection of Colorectal Cancer and Adenomatous Polyps, 2008: A Joint Guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology recommend the following as an option for the early detection of colorectal cancer in adults over 50 without symptoms:

Annual fecal immunochemical test with high test sensitivity for cancer.

They further point out:

Because small adenomatous polyps do not tend to bleed and bleeding from cancers or large polyps may be intermittent or simply not always detectable in a single sample of stool, the proper use of stool blood tests requires annual testing that consists of collecting specimens (2 or 3, depending on the product) from consecutive bowel movements.

When a test is positive, follow-up with colonoscopy that examines the entire length of the colon is required:

When performed for CRC screening, a positive gFOBT or FIT requires a diagnostic workup with colonoscopy to examine the entire colon in order to rule out the presence of cancer or advanced neoplasia.

The guidelines specifically specify high-sensitivity guaiac FOBT such as Hemoccult SENSA or fecal immunohistochemical tests (FIT) instead of the older guaiac FOBT.  The test should be done at home on three consecutive bowel movements.   There are some FIT tests that require fewer samples, and most FITs don’t have diet and medicine limits prior to testing, but they still need to be done more than once and at home.

The US Preventive Services Task Force also recommends annual high-sensitivity fecal occult blood testing as one option for colorectal cancer screening in average risk adults from 50 to 75.  USPSTF doesn’t directly address the issue of how to do that screening, but does embrace the idea of choice.

Because several screening strategies have similar efficacy, efforts to reduce colon cancer deaths should focus on implementation of strategies that maximize the number of individuals who get screening of some type. The different options for colorectal cancer screening tests are variably acceptable to patients; eliciting patient preferences is one step in improving adherence. Ideally, shared decision making between clinicians and patients would incorporate information on local test availability and quality as well as patient preferences.

SOURCE: Nadel et al. Journal of General Internal Medicine, online first April 10, 2010.  Open Access.

What This Means for Patients

Fecal occult blood testing (FOBT) is a recommended colorectal screening option for people of average risk.

It is especially useful for screening where there is limited access to sigmoidoscopy or colonoscopy.  Some patients may prefer it over options that are more invasive or require bowel preparation.  It  should be choice for you to consider.

However, it is critical that it be done right.

• Don’t accept a single test done in your doctor’s office during a rectal exam.  It will find so few cancers that it is useless.
• Ask for a high sensitivity guaiac FOBT or a fecal immunohistochemical test (FIT).  Medicare and most insurances will cover either one.
  
• Be sure to follow instructions carefully in the days before starting the test.  Complete all samples, and mail the test back.
• If your doctor doesn’t follow-up, call and find out if the results were normal.
• If the test is positive, insist on a colonoscopy.  Don’t accept a second test or a less complete examination of your entire colon.
  

Then repeat the test in a year.

In a study of  1,000 ethnically and racially diverse people, the lowest percentage had a colonoscopy when that was the only test offered.  More completed fecal occult blood testing if it was the single choice. Overall 65 percent of the 1,000 patients studied were screened after their doctor recommended testing.

Primary care providers randomly recommended patients be screened for colorectal cancer by:

• Colonoscopy alone
• FOBT alone
• Their choice of colonoscopy or FOBT

In order to make colonoscopy easier, barriers to having the exam were reduced by:

• Reducing or eliminating the patient’s cost for colonoscopy.
• Providing information about the test and preparation for it in the language the patient preferred.
• Providing rides to and from the exam.
• Having an open access system with no more than 2 weeks between test recommendation and the scheduled procedure date.

While two out of three participants in the study had a recommended test:

• 38.4 percent had a colonoscopy when it was the only recommendation.
• 67.1 percent completed an FOBT when only FOBT was recommended.
• 70.0 percent completed screening when they were given a choice between FOBT or colonoscopy.

During a follow-up survey, health beliefs that interfered with having a colonoscopy included

• Fear of test results.
• Fear of cancer treatment.
• Concern that they wouldn’t be able to do the necessary prep.

John M. Inadomi and colleagues in the GI Health Outcomes, Policy and Economics (HOPE) Research Program at the University of California,San Francisco concluded:

Recommendation of colonoscopy alone results in lower adherence to any colorectal cancer screening test compared with recommendation for fecal occult blood test alone or choice of FOBT or colonoscopy.

SOURCE: Inadomi et al., Digestive Disease Week Abstract #124.

Meeting for two days in Washington in February, a National Institutes of Health State-of-the-Science conference considered what is known– and not known– about why people choose or avoid screening, how to improve screening quality, and what the healthcare capacity is to deliver colorectal cancer screening to the US population.

At the end of the meeting, the panel released a consensus statement with their recommendations for enhancing the use and quality of colorectal cancer screening.

While the panel found that colorectal cancer screening rates were increasing, they still remain too low.  Rates moved from 20 to 30 percent of eligible people in 1997 to 55 percent in 2008, leaving millions of the population unscreened by any method.

To close the gap in screening, the panel identified the following priorities:

• Eliminate financial barriers to colorectal cancer screening and appropriate follow up.
• Widely implement interventions that have proven effective at increasing colorectal cancer screening, including patient reminder systems and one-on-one interactions with providers, educators, or navigators.
• Conduct research to assess the effectiveness of tailoring programs to match the characteristics and preferences of target population groups to increase colorectal cancer screening.
• Implement systems to ensure appropriate follow-up of positive colorectal cancer screening results.
• Develop systems to assure high quality of colorectal cancer screening programs.
• Conduct studies to determine the comparative effectiveness of the various colorectal cancer screening methods in usual practice settings.

In addition to underuse of screening, the panel found situations of overuse:  colonoscopies performed more often than guidelines recommend or patients with serious illness or limited life expectancy being screened without possible benefit.

They also identified misuse of screening when FOBT screening was done in an office setting rather using the recommended home tests.

The most important patient factors in getting screened, the panel discovered, were having insurance and having a usual source of medical care.  Higher income and socioeconomic levels also contributed to being screened.  Although there were lower rates of screening for African Americans and Hispanics, these disparities almost disappeared when insurance and socioeconomic factors were considered.

A recommendation from a physician was the only physician-related factor found that improved screening.  Practices that had electronic medical record reminder systems, staff who could facilitate follow-up arrangements, and patient navigators were the most successful in getting their patients screened.

Two healthcare systems had high screening rates.  Kaiser Permanente achieved a 75 percent screening rate for their Medicare patients, and the Veterans Administration system screens 75 percent of their eligible patients.  Both systems mail FOBT kits directly to patients, use focused reminders, and carefully follow-up all positive tests with colonoscopies.

The panel was concerned about capacity for colonoscopies, particularly for following up positive FOBT results.  They wrote:

Because it is unlikely that current capacity is sufficient for strategies other than universal FOBT screening, expansion of endoscopic capacity may be needed. A first step may be to examine the feasibility of increasing productivity or efficiency of existing facilities. Expanding high-quality endoscopy training to more providers, including nonphysicians, may also be warranted. Such expansion would require careful consideration of quality and patient satisfaction. Also needed is evaluation of the role of incentives, disincentives, and third-party payment policies for performing endoscopy.

In conclusion, the State-of-the-Science Panel wrote,

The panel found that despite substantial progress toward higher colorectal cancer screening rates nationally, screening rates fall short of desirable levels. Targeted initiatives to improve screening rates and reduce disparities in underscreened communities and population subgroups could further reduce colorectal cancer morbidity and mortality. This could be achieved by utilizing the full range of screening options and evidence-based interventions for increasing screening rates. With additional investments in quality monitoring, Americans could be assured that all screening achieves high rates of cancer prevention and early detection.

Unfortunately, FOBT or fecal occult blood testing does not find those polyps or cancers that are not bleeding. Depending on the sensitivity of the test, it may miss a fair percentage of cancers and most polyps. And the test may be falsely positive because of other conditions that cause intestinal bleeding, requiring unnecessary colonoscopy follow-up.

The latest 2007 Joint Guidelines for Screening recommend fecal occult blood testing as tests that primarily detect cancer.

However, FOBT has been shown in randomized clinical trials to reduce deaths from colorectal cancer by as much as one-third and is an important part of public health screening strategies.

All positive fecal occult blood tests need to be followed-up with a full colonoscopy to look for polyps or cancer.

There are two approaches to FOBT. The older guaiac-based test (gFOBT) measures one part of the hemoglobin molecule. A newer fecal immunochemical test (FIT) measures a different part. Globin, a protein measured by FIT, is only present in when bleeding occurs in the colon or rectum, eliminating false positives from stomach ulcers and bleeding in the the upper digestive tract or meat eaten before the test.

FOBTs are take-home test kits that are completed by patients. It is important that the tests be done accurately, including restricting certain drugs and foods before some tests and taking enough samples. Accuracy improves with the full number of samples and when the test is done every year.

Guaiac FOBT

Dietary and drug restrictions: When you use the guaiac-based FOBT such as Hemoccult®, it is important to avoid non-steroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen, naproxen, or more than one aspirin a day for seven days before testing. In addition red meat (beef, lamb, and liver) and vitamin C supplements, citrus fruits, and juices should be avoided for three days prior to the test.

Two small samples of three different bowel movements are smeared onto small paper squares. The kit is then returned to the doctor or mailed to a medical laboratory.

FIT

Fecal immunochemical tests (FIT) such as Hemoccult® ICT or InSure® have no drug or dietary restrictions, but it is important to avoid testing during the menstrual period or when there is rectal bleeding or bleeding from the urinary tract.

Samples are collected from bowel movements over two or three consecutive days. Some tests use a stick to collect stool, others use a small brush. None require actually touching the bowel movement.

Digital Rectal Exam

A single test done during a digital rectal exam in a doctor’s office is not sufficient for screening. The United States Preventive Services Task Force says,

Digital Rectal Examination/Office FOBT

There is little evidence to determine the effectiveness of either digital rectal examination or a single office FOBT using a stool sample obtained on DRE. Fewer than 10 percent of colorectal cancers arise within reach of the examining finger, and some of these lesions will already be symptomatic. The sensitivity of a single office FOBT is likely to be substantially lower than that of screening protocols involving multiple test cards: in one study the first test card would have missed 42 percent of cancers detected by screening. Samples collected by DRE may be affected by other limitations, including inadequate amount of stool or trauma from the exam.

Patient Instructions for Some FOBT and FIT screening tests.

Links to instructions are provided for preliminary information for you only. The most current instructions will be included with your test kit. Your doctor may suggest a different brand of test.

Hemoccult ® SENSA

Hemoccult ® ICT

InSure®