Evidence related to comparison of FIT and MT-sDNA tests

The MT-sDNA test and FIT were compared in a study including 9989 average-risk participants.15 This study found that MT-sDNA tests were more sensitive than FITs in detecting CRC, AA, SSA/P, nonadvanced findings, or negative findings for cancer. However, MT-sDNA testing results required more follow-up colonoscopies because of their lower specificity than the FIT. Of the 9989 participants, 455 had positive MT-sDNA test results but negative results on follow-up colonoscopy compared with 162 participants with positive FIT results and negative results on colonoscopy. This indicates that MT-sDNA tests produced a higher number of false-positives than FITs. Specificity in FITs was found to be higher than in the MT-sDNA test results. Both screening tests were determined to be noninvasive and more cost-effective overall than colonoscopy. Another study reviewed (with 661 participants) identified MT-sDNA testing as being superior to FITs in detection of CRC.16 This study’s findings were similar with those from other studies: MT-sDNA tests had lower specificity rates than FITs. 

The MT-sDNA test was used along with the FIT to detect SSA/Ps (flat lesions that are difficult to detect with FIT alone) and was found to be effective in testing for the SSA/P biomarker, mBMP3.17 All FITs assess for Hgb concentration to detect CRC, but this may be absent in nonhemorrhagic SSA/Ps. The authors concluded that the 2 screening tools, FIT and MT-sDNA, were comparably effective in detecting CRC and other precancerous conditions of the colon. 

Discussion

Colorectal cancer screening continues to be an important field of research. For this literature review, several research studies were included on the use of the FIT and the MT-sDNA test as noninvasive options for colorectal cancer screening. Each of these tests has different levels of evidence to support their use and ability to detect cancerous and precursor lesions. This literature review was completed to provide more knowledge on the FIT and MT-sDNA test so providers can make evidence-based decisions on what screening option best suits their patients. 

Strengths

There were several strengths in the studies included in this literature review regarding the MT-sDNA. Both of the studies focused solely on average-risk participants, which represented diverse populations.13.14 One study intentionally collected stool samples from multiple test sites.13 The other study demonstrated uniform collection and analyses by obtaining samples before screening colonoscopies.14 

Many strengths were also identified concerning the FIT. Several studies focused solely on average-risk participants.5,10,12 Other studies included average-risk participants, although not exclusively.6,7,9,11 One study assessed the average-risk population with 4 rounds of FIT testing.5 Grobbee et al included previously screened individuals and newly screened individuals in their study.9 Chang et al included asymptomatic individuals who completed a colonoscopy as part of a general health check-up not specific for CRC screening purposes.11 Two of the studies included high return rates of the tests and high compliance rates among participants.9,10 Grobbee et al reported an adherence rate for a colonoscopy after a positive FIT of 90%, so they were able to adequately compare their results.9 Levy et al achieved their original goal of 700 participants with returned FITs.10 Statistical significance was reached in the study completed by Cubiella et al.6 In addition, experienced gastrointestinal pathologists were used to avoid interobserver bias.7,11

Three articles included in this literature review are head-to-head comparisons of the FIT and MT-sDNA test,15-17 and it is also important to note their strengths. One included a very large sample size of 9989 participants.15 Two included only average-risk participants.15,17 One study found that the FIT detected a majority of sessile serrated polyps despite a relatively narrow and small size range.17 

Limitations

Limitations of the MT-sDNA studies included in this literature review are also important to mention. First, only 2 articles focused on the use of the MT-sDNA test alone.13,14 This is likely related to the MT-sDNA test being a relatively new technology. Another limitation is that certain important factors were not well-controlled in both of these studies. For instance, 1 study collected stool samples both before and after a colonoscopy.14 The other study collected archived stool samples in a buffer from different storage facilities, and storage procedures were inconsistent.13 One study featured a case-control design but did not include a validation set, which can result in an overestimation of the test performance.14 Other limitations to the studies reviewed pertain to pathology measurements not always being available, the quality of the colonoscopy not being controlled, and the use of the HemoQuant, which can detect both upper and lower gastrointestinal bleeding (possibly skewing results).13