High test positivity and low positive predictive value for colorectal cancer of continued faecal occult blood test screening after negative colonoscopy

Abstract

ObjectivesThe English Bowel Cancer Screening Programme offers biennial guaiac faecal occult blood test (gFOBT) screening to 60–74-year-olds. Participants with positive results are referred for follow-up, but many do not have significant findings. If they remain age eligible, these individuals are reinvited for gFOBT screening. We evaluated the performance of repeat screening in this group.MethodsWe analysed data on programme participants reinvited to gFOBT screening after either previous negative gFOBT (n = 327,542), or positive gFOBT followed by a diagnostic investigation negative for colorectal cancer (CRC) or adenomas requiring surveillance (n = 42,280). Outcomes calculated were uptake, test positivity, yield of CRC, and positive predictive value (PPV) of gFOBT for CRC.ResultsFor participants with a previous negative gFOBT, uptake in the subsequent screening round was 87.5%, positivity was 1.3%, yield of CRC was 0.112% of those adequately screened, and the PPV of gFOBT for CRC was 9.1%. After a positive gFOBT and a negative diagnostic investigation, uptake in the repeat screening round was 82.6%, positivity was 11.3%, CRC yield was 0.172% of participants adequately screened, and the PPV of gFOBT for CRC was 1.7%.ConclusionWith high positivity and low PPV for CRC, the suitability of routine repeat gFOBT screening in two years among individuals with a previous positive test and a negative diagnostic examination needs to be carefully considered.

Faecal immunochemical tests (FIT) versus colonoscopy for surveillance after screening and polypectomy: a diagnostic accuracy and cost-effectiveness study

“…Intermediate-risk patients are currently recommended to undergo surveillance until they have two consecutive negative colonoscopies 45. Stopping rules for FIT-based surveillance would have to consider the susceptibility of some patients to repeatedly test false positive; something we observed in our analysis of BCSP participants who underwent gFOBT screening 46…”

A Qualitative Transcriptional Signature for the Risk Assessment of Precancerous Colorectal Lesions

“…Colonoscopy is an essential step in the diagnosis of CRC with 4–21% inaccurate rate ( Stanciu et al, 2007 ; Huang et al, 2016 ), which is mainly influenced by the image quality and the endoscopists’ experience ( Costamagna and Marchese, 2010 ; Kaminski et al, 2010 ; Tumino et al, 2017 ). Currently, established non-invasive tests, such as the fecal occult blood test (FOBT), have a low sensitivity ( Schottinger et al, 2016 ) and positive predictive value ( Azimafousse Assogba et al, 2015 ; Brown et al, 2018 ). Methylated Septin9 ( m SEPT9) has superior sensitivity compared to FOBT, which range from 36.6 to 95.6% ( Warren et al, 2011 ; Ahlquist et al, 2012 ; Toth et al, 2012 ; Lee et al, 2013 ; Church et al, 2014 ).…”

A qualitative transcriptional signature for the early diagnosis of colorectal cancer

“…However, most CRC patients are diagnosed with middle or advanced stage disease . Currently, established noninvasive tests, such as the guaiac‐based fecal occult blood test, have a low sensitivity and positive predictive value . Several serum protein biomarkers, including carcinoembryonic antigen, CA19.9, and CA125, can be used for monitoring the prognosis of CRC patients but none of them are recommended for the early diagnosis of CRC .…”

“…3 Currently, established noninvasive tests, such as the guaiac-based fecal occult blood test, have a low sensitivity 4 and positive predictive value. 5,6 Several serum protein biomarkers, including carcinoembryonic antigen, CA19.9, and CA125, can be used for monitoring the prognosis of CRC patients but none of them are recommended for the early diagnosis of CRC. 7,8 The expression of TSP50 has also been proposed as a diagnostic signature for CRC, 9 but its sensitivity, specificity, and positive predictive value were 68.4%, 92.5%, and 95.6%, respectively.…”