FIT Performance in Early-Stage Colorectal Cancer—Response Free

See the original Letter to the Editor, p. 1562

We would like to thank Dr. Boncz and colleagues for sharing their experience with their proprietary fecal immunochemical test (FIT) in colorectal cancer (CRC) screening in Hungary. Considering the Hungarian data, 2 questions arise. At first, curiosity rises on the positivity rate in the initial pilot screening round in Hungary. A sensitive guaiac-based fecal occult blood test (G-FOBT) was used, for which the positivity rate of 29% is remarkably high. Most studies on G-FOBT in CRC screening show positivity rates of 2.4% to 4.7%, depending on which type of G-FOBT was used (1–3). Second, it is unclear how sensitivity and specificity were calculated in the second Hungarian screening round using a FIT. We assume that these values were calculated indirectly, as only FIT-positive screenees underwent colonoscopy. In our recent study on FIT performance in early-stage CRC, all participants underwent complete colonoscopy. This might explain some of the differences found in test characteristics between their program and our study. A full appraisal of the merits of the test described by Dr. Boncz and colleagues would require a more extensive comparison of their proprietary test against an established test, like the one we used, than can be described in a letter (4).