The lack of dietary restrictions makes this a more patient-friendly test than the gFOBT (Smith et al.
The specificity for DNA tumor markers eliminates the dietary and medication restrictions of the gFOBT (Ahlquist, 2002; Ahlquist & Shuber, 2002; Helm et al.
While a 30% false-negative rate for gFOBT may seem alarming, it is important to note colonoscopy, the "gold standard," is not a perfect test either.
The gFOBT has a 30% false-positive rate, which may be due to bleeding from the upper GI tract (van Ballegooijen et al.
The increased sensitivity of the iFOBT makes intermittent tumor bleeding a less significant issue than with the gFOBT (Levin et al.
The challenge of patient compliance with CRC screening has prompted many physicians to use the in-office DRE gFOBT (Collins et al.
The iFOBT has had a 30% increase in compliance over the gFOBT due to the better sampling method (Cole et al.
Screening with the gFOBT reduces morbidity by 20% (Mandel et al.
TABLE 1 Current recommendations for colorectal cancer screening in average-risk individuals Who Recommended tests & frequency (a) Invasive Beginning Until age C FS CTC DCBE age USPSTF 2008 (10,b) 50 y 75 y 10 y 5 y American 50 y 75 y or life 10 y 5 y College of expectancy Physicians <10 y 2012 (9) American Cancer 50 y NS 10 y 5 y 5 y 5 y Society 2015 (2) Recommended tests & frequency (a) Noninvasive High FIT Multi- sensitivity target gFOBT
sDNA USPSTF 2008 (10,b) 1 y 1 y American 1 y 1 y UC (c) College of Physicians 2012 (9) American Cancer 1 y 1 y 3 y Society 2015 (2) (a) Assumes no evidence of disease.
A major disadvantage of gFOBT and FIT is that these tests assess only bleeding, which may be sporadic and could result from causes other than CRC.
Unlike other noninvasive tests such as gFOBT and FIT, multitarget sDNA testing has increased sensitivity for precancerous lesions and CRC in both the proximal and distal colon.