Result card

  • EFF31: Does FIT for CRC screening reliably rule in or rule out adenomas and CRC?
English

Does FIT for CRC screening reliably rule in or rule out adenomas and CRC?

Authors: Jesús González-Enríquez, Francesca Gillespie, Stefania Lopatriello, Iñaki Imaz

Internal reviewers: Pseudo125 Pseudo125

Please refer to EFF 20.

A high-quality review indicated that sensitivities were higher for the detection of CRC, and lower for adenomas, in both the diagnostic cohort and diagnostic case–control studies for both guaiac and immunochemical FOBTs {17}. Another review with lower quality due to unclear design and quality assessment of selected studies, compared sensitivity and specificity of the colorectal cancer mass screening methods: colonoscopy was reported as the one with best sensitivity and specificity while fecal occult blood test with the lowest. The mean ± standard deviation per patient sensitivities and specificity of colonoscopy respectively 94.7 ± 4.6 % and  99.8  ±  0.2% (compared to FOBTs 45.7 ± 26.5% 87.6 ± 11.4%) {22}.

 

A large population study found that the sensitivity of FIT for non-advanced adenomas, advanced adenomas, and cancer was 10.6%, 28.0%, and 78.6%, respectively. The sensitivity of FIT for advanced polypoid neoplasm (31.1%) was significantly higher than that of nonpolypoid ones (21.1%) (P <.001){27}. Furthermore, the sensitivity of FIT was in relation to neoplasm stage: FIT sensitivity showed stage-dependence and was 28.0% for advanced adenomas, 73.9% for invasive cancer, 66.7% for Tis plus T1 cancers, and 100% for T2 to T4 cancers (P for trend < .001){27}. The specificity was similar in relation with stage: 92.8% for invasive cancer, Tis plus T1 cancer and T2-T4 cancer.

 

Finally, the sensitivity of FIT for advanced neoplasms was in relation to location and morphology: the sensitivity was significantly lower for proximal polypoid advanced neoplasms compared with distal ones (27.7% vs 31.6%; P < .001) and proximal nonpolypoid advanced neoplasms compared with distal ones (16.2% vs 24.3%; P < .001) {27}. The trend was similar when proximal and distal, polypoid and nonpolypoid advanced adenomas were compared. For invasive cancers, although there was a trend toward lower sensitivity for proximal lesions, the result was not statistically significant {27}.

 

The I-FOBTs were significantly better than the G-FOBTs in detecting both cancers and advanced adenomas. The detection of cancers was at least twice as high with the I-FOBT as with the G-FOBT, and the number of advanced adenomas was about three to four times as high{19}. The same study also assessed detection according to stage of cancers at diagnosis: the proportion of Tis and stage 1 cancers was higher with I-FOBTs than with the G-FOBT. The differences between I-FOBTs and G-FOBTs, however, were not significant{19}. However, results need to be validated with cut off levels assessed in the faeces and not in the buffer solution {19}.

 

When applied on as second round test, the results reported here show that, despite a significant decrease in the PPV for CRC, a substantial number of significant lesions were detected; this applies more to advanced adenomas than to cancer cases and appears to be independent of the type of test used in the first round (guaiac FOBT or FIT) {28}.

 

FITs capability of reliably ruling in or out adenomas and CRC depends not only on its accuracy measures, but also on threshold and appropriate Mean Sejourn Time. Both of these issues need further research. Also refer to research question EFF15 for other factors influencing accuracy measures.

Important
Partially
González-Enríquez J et al. Result Card EFF31 In: González-Enríquez J et al. Clinical Effectiveness In: Jefferson T, Cerbo M, Vicari N [eds.]. Fecal Immunochemical Test (FIT ) versus guaiac-based fecal occult blood test (FOBT) for colorectal cancer screening [Core HTA], Agenas - Agenzia nazionale per i servizi sanitari regionali; 2014. [cited 21 June 2021]. Available from: http://corehta.info/ViewCover.aspx?id=206

References