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FIT more acceptable with better detection rate than gFOBT for colorectal cancer screening
Clinical Question
Are the uptake and detection rates better for the fecal immunochemical test than for older guaiac-based screening tests for colorectal cancer?
Bottom line
The fecal immunochemical test (FIT) is more sensitive and specific than the older guaiac-based fecal occult blood tests (gFOBTs) when screening for colorectal cancer. We now know that it is also more acceptable to patients and increases uptake in a centrally administered screening program. Physicians should offer patients the option of FIT or colonoscopy, and should replace their stocks of gFOBTs with FITs in their office practice. 1b
Reference
Study design: Non-randomized controlled trial
Funding: Government
Setting: Population-based
Synopsis
Previous randomized trials have shown that screening for colorectal cancer, even using the older gFOBTs, reduces disease-specific mortality. The most recent modeling estimates put this benefit at 220 to 270 life-years saved per 1000 persons screened over their lifetime (https://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/colorectal-cancer-screening2). The FIT is a newer test for occult blood in the stool that is specific to human blood, and only requires a single sample with no food restrictions prior to testing. But do these advantages translate into greater uptake by patients? In England, the standard of care has been to mail 3 gFOBT cards to all persons aged 60 years to 74 years every 2 years, and ask them to obtain 2 samples from each of 3 separate bowel movements. The current study gave every 28th person (in a region with 1.2 million screening candidates) the newer FIT; the other 27 people got the standard gFOBT. Although not randomized, the authors assure us that the order of persons on the screening list is not influenced by age, sex, socioeconomic status, or other demographic factors. They found that the uptake was significantly higher for the FIT than for gFOBTs (66.4% vs 59.3%; P < .001). Uptake increased for both men and women in all age groups and in all levels of socioeconomic status. The increase in uptake was somewhat greater in men than in women. And among previous nonresponders, the response rate approximately doubled. At lower cutoffs for hemoglobin, the number of colonoscopies required increased three- to fourfold, but the detection rate for cancers and advanced adenomas was also significantly higher. For example, using a cutoff of 40 mcg/g feces, 5.2% of persons had a positive FIT result compared with 1.7% using gFOBTs; the rates of cancer and advanced adenoma detection were 0.24% and 1.29% with the FIT, and only 0.12% and 0.35% with gFOBTs.
Reviewer
Mark H. Ebell, MD, MS
Professor
University of Georgia
Athens, GA
Comments
Is it available in Canada ?!
FIT results in BC were returning 20% false positives in British Columbia last year. Tests were ordered withdrawn pending further study
Although one is reluctant to ask a prosaic "cost per unit" question of an entity which appears to be more efficient in positively screening for a diagnosis, is there relevant cost data available for the FIT vice FOBT?
I guess most of us will not be asking.
I am asking since I have clinical epidemiology training and don't think the format of this presentation is either efficient or convincing (I haven't read the full paper- just your POEM) .
It would be more appropriate to compare both tests in terms of sensitivity and specificity or likelihood ratios rather than cancer "uptake" rates (do the authors mean positive predictive values ?? It wasn't clear). These rates are driven by prevalence in the screened populations and are not true properties of the tests.
Good poem
I do not know how can I arrange this test.
Just waiting for Ontario to make these the norm!
We have already switched to using the FIT.
This makes me more comfortable about that choice.
It would be nice if we moved to doing FIT in the hospital setting as well as it would likely help the workload in the hospital as well.
Province of NB already doing this