Immunochemical vs guaiac faecal occult blood tests in a population-based screening programme for colorectal cancer

Abstract

Summary Two faecal occult blood tests (FOBTs), Hemoccult II (guaiac based) and Hemeselect (immunochemical) were compared in a population screening for colorectal cancer on 24 282 subjects aged 40-70. Hemeselect was interpreted according to a lower (+ and +) and a higher (+) positivity threshold. A total of 8008 compliers were enrolled in the study. Positivity rates: Hemoccult=6.0%, Hemeselect (+ and ±) = 8.2%, Hemeselect (+) = 3. 1%. Among FOBT-positive subjects complying with the diagnostic work-up, 22 had colorectal cancer (17 Hemeselect-positive (+), four Hemeselect-borderline (±), 15 Hemoccult-positive) and 166 subjects had adenomas (62 Hemeselect(+), 56 Hemeselect-borderline (±), 79 Hemoccult-positive) were detected. The positive predictive values (PPVs) for cancer were as follows: Hemoccult =3.7%, Hemeselect (+ and +) = 3.8%, Hemeselect (+) =8.4%. The PPVs for adenoma(s) were: Hemoccult = 19.7%, Hemeselect (+ and +) =21.4%, Hemeselect (+) =30.5%. The specificity for cancer was: Hemoccult =94.1%, Hemeselect (+ and +) = 92%, Hemeselect (+) = 97.1%. Ratios between detection rates of each test and expected incidence of colorectal cancer suggest that Hemoccult anticipates cancer diagnosis by approximately 2 years on average whereas the mean diagnostic anticipation of Hemeselect ranges between 2.5 and 3.2 years. Hemeselect is superior to Hemoccult as it is at least as effective but more efficient and acceptable than guaiac testing. Further evaluation of Hemeselect cost-effectiveness and sensitivity is needed in order to assess the optimal threshold of positivity and screening frequency.

Association of FOBT-assessed faecal Hb content with colonic lesions detected in the Florence screening programme

“…This, combined with the association of Hb content with adenoma characteristics, and with the adoption of a 100 ng ml À1 Hb positivity threshold, allowed for a favourable advanced/not advanced adenoma ratio of approximately 3 : 1 (669/221), as compared to approximately 1 : 1 when guaiac FOBT was employed (Castiglione, 1996).…”

“…The detailed features of the screening programme, inviting residents in the 50 -70 years age group to biennial FOBT, have been described elsewhere (Castiglione et al, 1996(Castiglione et al, , 2000Zappa et al, 1997).…”

“…The Florence FOBT population-based screening programme, run by the Centro per lo Studio e la Prevenzione Oncologica (CSPO) since 1982, was confirmed to be effective by means of a case -control study : adjusted odds ratio for death from CRC for screened vs not screened subjects was 0.60 (95% CI: 0.4 -0.9). The programme shifted from guaiac to I-FOBT in 1995, after favourable comparison studies with guaiac FOBT (Castiglione et al, 1996(Castiglione et al, , 2000 and positivity cutoff was set at a 100 ng ml À1 Hb level (Castiglione et al, 2002). Faecal occult blood testing screening has often been criticised for its limited specificity, Spurious guaiac-based FOBT positivity has not been eliminated with the introduction of I-FOBT, owing to non-neoplastic intestinal bleeding, and the efficacy of FOBT screening has been claimed to be, at least partially, the effect of a large cumulative use of colonoscopy, prompted by spurious FOBT positivity at repeat screening (Lang and Ransohoff, 1994;Ederer et al, 1997).…”

Evaluation of a Colorectal Carcinoma Screening Program in Kota Setar and Kuala Muda Districts, Malaysia

“…On top of that, utilization of either immunochemical or guaiac FOBT could have attributed to difference in positivity rate between all of the studies aforementioned. Immunochemical FOBT was found to be more superior than guaiac FOBT (Castiglione et al, 1996;Launoy et al, 2005). The aforementioned studies in England (Moss et al, 2011;Logan et al, 2012), Scotland and France (Leuraud et al, 2013) were utilizing guaiac as compared to immunochemical FOBT was used in Japan (Oono et al, 2010) and our study.…”

Fecal Cyclooxygenase 2 Plus Matrix Metalloproteinase 7 mRNA Assays as a Marker for Colorectal Cancer Screening

“…In a recent review, the sensitivity of FOBT using guaiac-based tests for CRC detection was reported as 26% in asymptomatic nonreferred populations (33). IFOBTs were recommended for CRC screening due to the higher sensitivity than guaiac-based tests (7,(34)(35)(36). In fact, a single IFOBT was reported to have 65.8% sensitivity for detecting invasive CRC (37).…”