The computer model looked at 100,000 average risk people and compared screening methods results for

• number of colorectal cancer cases
• number of colorectal cancer deaths
• cost of screening and treating colorectal cancer for each screened person

Compared to not screening at all, annual FIT  could save 3 out of 4 deaths from colorectal cancer. For every 100,000 people between 50 and 75, nearly 3,500 people wouldn’t get colorectal cancer, and over 1,300 wouldn’t die.

Not only did FIT screening save the most lives, it was the most cost effective.  It saved about $70 (Canadian) in screening and cancer treatment expenses for each person screened, better than any other method.

FIT vs Colonoscopy

Steven Heitman,of the University of Calgary in Alberta and and his team found

• If no one was screened at all, there would be 4,857 cases of colon or rectal cancer and 1,782 deaths over the lifetime of every 100,000 people in North America.
• Annual testing with FIT reduced cases of colorectal cancer to 1,393 and deaths to 457.
• Colonoscopy done every ten years, with follow-up exams every 3 to 5 years when polyps were found, would reduce cases to 1,825 and deaths to 624.

While FIT was more effective than colonoscopy, it needed to be done every year, while colonoscopy screening is recommended every ten years.  The researchers  wrote,

Although it may seem counterintuitive that screening with FIT could be even more effective than colonoscopy, this is due to the more frequent screening interval with FIT.

The computer assumed that patients would adhere to a program of annual testing with follow-up colonoscopy for positive testing 63 percent of the time.  When adherence fell below 40 percent, colonoscopy became a better option.

Healthcare Costs of Screening and Cancer Treatment

In considering health care costs, the research team included the cost of screening itself, follow-up colonoscopy when required, treating bleeding or perforation complications of colonoscopy or CT colonography, and the cost of recommended surgery and chemotherapy for each stage of cancer.  They also included expenses for time and travel for patients and caregivers.  All costs were reported in 2008 Canadian dollars.

All methods included in the model were considered to be done at the recommended intervals, with appropriate follow-up.  .

Per person screened, the cost of screening and recommended cancer treatment, including biologics for stage IV cancer:

• FIT –$1,833
• No screening — $1,901
• High sensitivity FOBT — $2,084
• Colonoscopy — $2,100
• Low sensitivity FOBT — $2,192
• Flexible sigmoidoscopy — $2,263
• CT colonography– $2,409
• Fecal DNA test (2nd standard) — $2,491
• Fecal DNA (first standard) — $2,720

FIT vs Other Screening Methods

A fecal immunchemical test with mid-level sensitivity was more effective than any other screening method overall.  A higher sensitivity FIT reduced cancers and cancer deaths, but cost more.  A low sensitivity test, with only one sample, was less effective overall — costing more and reducing fewer cases and deaths.

In conclusion, Steven J. Heitman and colleagues at the University of Calgary in Alberta, wrote,

CRC screening with FIT reduces the risk of CRC and CRC-related deaths, and lowers health care costs in comparison to no screening and to other existing screening strategies. Health policy decision makers should consider prioritizing funding for CRC screening using FIT.

Although FIT proved the best at preventing new cancers and cancer deaths, all the screening methods studied were better than no screening at all.

Colorectal cancer screening saves lives!

The American Cancer Society has an excellent review of the current screening guidelines with detailed descriptions of each of the screening methods that were modeled.

SOURCE:  Heitman et al., PLoS Medicine, November 23, 2010.  An Open Access article from the Public Library of Medicine.

What Does This Mean for Patients?

This study offers more information about effective ways of screening for colorectal cancer.

Although you may have considered colonoscopy the “gold standard”,  this research demonstrates that for a large group of people, annual FIT testing actually prevents more cases of cancer and saves more lives.

If the risks of colonoscopy screening concern you, choosing FIT might be a choice for you.  If you do you need to be sure:

• You are willing to do the test every year.
• You realize that a positive test needs colonoscopy follow-up and you are willing to do that.
• Your doctor explains the sensitivity of the different FIT tests and you are given one that has mid to high level sensitivity.
• You get clear instructions for completing the test at home and mailing it back.
• You are an average risk person with no family or personal risks for colorectal cancer.

FIT might also be an affordable choice for people without insurance — although if positive, colonoscopy is necessary.

FIT is a different fecal test than the more commonly used FOBT — fecal occult blood test.  In the computer model, FOBT screening prevented the fewest cancers and saved the fewest lives except for the earlier version of fecal DNA testing.  Be sure that the test you are getting is a fecal immunochemical test.

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.

Comparing Screening Methods for Average Risk Patients

Tests that Detect Adenomatous Polyps and Cancer

Colonoscopy

Most sensitive test for small and large polyps and cancers. Examines the entire colon, polyps can be removed and biopsied during the procedure.

Expensive, requires complete bowel cleansing. Normally uses sedation and requires someone to accompany patient, Rare instances of bowel perforation and bleeding. May not be covered by insurance.

Double-contrast barium enema

Every 5 years

Visualizes the entire colon, can detect most cancers, and the majority of large polyps. Helps patients who cannot complete a colonoscopy or where colonoscopy is not medically appropriate. Less expensive.

Requires complete bowel preparation. May be uncomfortable. An experienced radiologist is critical to quality exam. Colonoscopy is still required to biopsy lesions or removed polyps.

CT-colonography (virtual colonoscopy)

Every 5 years

Does not require sedation. No recovery time, patients can drive home or return to work. Finds cancer and large polyps at the same rate as colonoscopy. May find problems outside the colon as well.

Requires complete bowel preparation. Colonoscopy is required to biopsy and remove polyps. Technology and radiologist training are growing but not complete. May not detect non-polypoid colorectal neoplasms. May not be covered by insurance. False-positive problems identified outside the colon may require unnecessary follow-up tests.

Flexible sigmoidoscopy

Every 5 years

Can be done by primary care physician or trained nurse practitioner. Does not require sedation

Will miss polyps or cancers in the right colon beyond the reach of the scope. If polyps are found, colonoscopy and addition bowel preparation are required. Can be uncomfortable.

Tests that Primarily Detect Cancer

gFOBT: Guaiac-based stool test

Every year

Not very sensitive to polyps, will miss some cancers. Needs to be done correctly over three days. Requires diet and drug restrictions. Patients must handle stool. Has a high false positive rate that requires follow-up colonoscopy for about 1 in 3 tests.

FIT: Immunochemical stool test

Will miss some cancers and most advanced polyps. More expensive than gFOBT. All positive tests require colonoscopy follow-up.

Done at home privately. Not necessary to handle stool. Collection kit shipped directly to patient. No special diet prep required.

May not find all cancers or large polyps. Requires prompt, ice-pack shipment to special labs. Significantly more expensive than gFOBT or FIT. Colonoscopy follow-up necessary for positive test.