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Reducing the Cut-Off Value of the Fecal Immunochemical Test for Symptomatic Patients Does Not Improve Diagnostic Performance.

ABSTRACT: Introduction: The fecal immunochemical test (FIT) has been established as a cost-effective test in colon cancer screening programmes. This test could also be helpful in symptomatic patients prior to colonoscopy, but data about diagnostic performance, and accurate cut-off values for these patients are still scarce. Materials and Methods: Prospective study that included consecutive unselected patients with gastrointestinal symptoms referred for colonoscopy between November 2016 and June 2018. We performed a FIT (FOB Gold® test, cut-off 20 micrograms of Hb/gram of feces) prior to colonoscopy and determined the accuracy of FIT in terms of sensitivity, specificity, positive and negative predictive value for clinically significant pathology, advanced neoplasia, and colorectal cancer in symptomatic patients, using two different cut-off values. Results: A total of 727 patients (44.3% men, aged 58.5 ± 14.9 years) was included in the study. The main symptom was history of previous (non-active) rectal bleeding (34.7%), followed by diarrhea (15.0%). Over one quarter of the patients (25.9%) had a positive FIT result. The caecal intubation rate was 95.5%. Clinically significant pathology was identified in 142 colonoscopies (19.5%), advanced neoplasia in 115 (15.8%) and colorectal cancer in 36 colonoscopies (5.0%). FIT performed very well for clinically significant pathology, advanced neoplasia and cancer, with a high negative predictive value (NPV). Reducing the cut-off value to 10 ?g/g yielded similar NPV results, with a decrease in specificity. Using a combination of symptoms with a positive FIT result did not improve FIT performance. Only specificity was slightly higher compared to FIT alone, but this was paralleled by a decrease in sensitivity and NPV for cancer and clinically significant pathology. The odds of presenting clinically significant pathology, advanced neoplasia, or cancer increased with FIT concentration. Conclusions: The specificity and NPV of FIT for clinically significant pathology, advanced neoplasia, and cancer are high in symptomatic patients. FIT is a helpful test for determining the need to perform further studies. It may not be necessary to reduce the cut-off value for symptomatic patients, since FIT performance with the current standard cut-off value used in colorectal cancer screening was accurate. FIT can be used to avoid or prioritize colonoscopy procedures.

SUBMITTER: Navarro M

PROVIDER: S-EPMC7492376 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Reducing the Cut-Off Value of the Fecal Immunochemical Test for Symptomatic Patients Does Not Improve Diagnostic Performance.

Navarro Mercedes M Hijos Gonzalo G Sostres Carlos C Lué Alberto A Puente-Lanzarote Juan Jose JJ Carrera-Lasfuentes Patricia P Lanas Angel A

Frontiers in medicine 20200902

<b>Introduction:</b> The fecal immunochemical test (FIT) has been established as a cost-effective test in colon cancer screening programmes. This test could also be helpful in symptomatic patients prior to colonoscopy, but data about diagnostic performance, and accurate cut-off values for these patients are still scarce. <b>Materials and Methods:</b> Prospective study that included consecutive unselected patients with gastrointestinal symptoms referred for colonoscopy between November 2016 and J ...[more]

PMID: 32984360

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Project description:Background & aimsNoninvasive tests used in colorectal cancer screening, such as the fecal immunochemical test (FIT), are more acceptable but detect neoplasias with lower levels of sensitivity than colonoscopy. We investigated whether lowering the cut-off concentration of hemoglobin for designation as an abnormal FIT result increased the detection of advanced neoplasia in a mailed outreach program.MethodsWe performed a prospective study of 17,017 uninsured patients, age 50 to 64 years, who were not current with screening and enrolled in a safety-net system in Texas. We reduced the cut-off value for an abnormal FIT result from 20 or more to 10 or more ?g hemoglobin/g feces a priori. All patients with abnormal FIT results were offered no-cost diagnostic colonoscopy. We compared proportions of patients with abnormal FIT results and neoplasia yield for standard vs lower cut-off values, as well as absolute hemoglobin concentration distribution among 5838 persons who completed the FIT. Our primary aim was to determine the effects of implementing a lower hemoglobin concentration cut-off value on colonoscopy demand and yield, specifically colorectal cancer (CRC) and advanced neoplasia detection, compared with the standard, higher, hemoglobin concentration cut-off value.ResultsThe proportions of patients with abnormal FIT results were 12.3% at the 10 or more ?g hemoglobin/g feces and 6.6% at the standard 20 or more ?g hemoglobin/g feces cut-off value (P = .0013). Detection rates for the lower vs the standard threshold were 10.2% vs 12.7% for advanced neoplasia (P = .12) and 0.9% vs 1.2% for CRC (P = .718). The positive predictive values were 18.9% for the lower threshold vs 24.4% for the standard threshold for advanced neoplasia (P = .053), and 1.7% vs 2.4% for CRC (P = .659). The number needed to screen to detect 1 case with advanced neoplasia was 45 at the lower threshold compared with 58 at the standard threshold; the number needed to scope to detect 1 case with advanced neoplasia increased from 4 to 5. Most patients with CRC (72.7%) or advanced adenoma (67.3%) had hemoglobin concentrations of 20 or more ?g/g feces. In the group with 10 to 19 ?g hemoglobin/g feces, there were 3 patients with CRC (3 of 11; 27.3%) and 36 with advanced adenoma (36 of 110; 32.7%) who would not have been detected at the standard positive threshold (advanced neoplasia Pcomparison < .001). The proportion of patients found to have no neoplasia after an abnormal FIT result (false positives) was not significantly higher with the lower cut-off value (44.4%) than the standard cut-off value (39.1%) (P = .1103).ConclusionsIn a prospective study of 17,017 uninsured patients, we found that reducing the abnormal FIT result cut-off value (to ?10 ?g hemoglobin/g feces) might increase detection of advanced neoplasia, but doubled the proportion of patients requiring a diagnostic colonoscopy. If colonoscopy capacity permits, health systems that use quantitative FITs should consider lowering the abnormal cut-off value to optimize CRC detection and prevention. (ClinicalTrials.gov no: NCT01946282.).

Project description:BACKGROUND & AIMS:The fecal immunochemical test (FIT) is an alternative to colonoscopy and can increase overall screening for colorectal cancer (CRC). However, little is known about the frequency of and reasons for mishandled FIT samples. METHODS:We performed a prospective study, nested within a randomized controlled trial of patients, recruited from December 2015 through August 2017, who were not up to date with colorectal cancer screening (50-75 years old). The patients were randomly assigned to usual care or outreach groups that received a mailed FIT with low literacy level instructions or a reminder call, or both. We examined frequency of and reasons for mishandled FIT samples, including absence of collection date; time from collection to laboratory receipt of more than 14 days; or mishandling of stool, buffer, or cap. The outcomes were the frequency of mishandled FIT samples, effects of outreach on mishandling, and positive results from the FIT among proper and mishandled samples. RESULTS:FIT samples were returned from 1871 patients assigned to usual care and 3045 who received the low literacy level instructions and a reminder call. In total, 19.8% of samples were mishandled; most of these (93.7%) had not labeled the date of stool collection but were still processed. Of the received samples, 1.2% of were not processed because the time from patient collection to laboratory receipt was more than 14 days. Outreach was associated with a lower proportion of mishandled samples (16.5% vs 25.0% for usual care; P < .0001). The proportion of mishandled samples was lowest among patients who received the low literacy level instruction and a reminder call (12.8%, P < .0001). There was no significant difference in proportions of positive results between properly processed samples (7.5%) and improperly processed samples (6.2%) (P = .14). CONCLUSION:In a prospective study of patients who were not up to date with colorectal cancer screening, we found that almost 20% of FIT samples were mishandled, with most patients missing the stool collection date. Patient outreach was associated with a lower proportion of mishandled samples, but there was no difference in proportions of positive results between properly and improperly handled samples. Our findings indicate that routine processing of undated FIT samples is associated with similar rates of positive results. There are limited data on test characteristics for FIT samples beyond the 14 days of stool acquisition. The inclusion of low literacy level instructions with reminder calls was associated with improved patient handling of the FIT sample. ClincialTrials.gov no: NCT02613260.

Project description:BackgroundFor colorectal cancer (CRC) screening to improve survival, patients with an abnormal fecal immunochemical test (FIT) must follow-up with a diagnostic colonoscopy. Adherence to follow-up is low and patient-level barriers for suboptimal adherence have yet to be explored.ObjectiveTo characterize barriers for non-completion of diagnostic colonoscopy after an abnormal FIT reported by under- and uninsured patients receiving care in a safety-net health system.DesignA longitudinal, cohort study of CRC screening outreach to 8565 patients using mailed FIT kits. Patients with abnormal FIT results received telephonic navigation to arrange for a no-cost diagnostic colonoscopy.PatientsAdults aged 50-64 years receiving care at a North Texas safety-net health system.ApproachDescriptive analyses characterized the patient sample and reasons for lack of follow-up after abnormal FIT over the 3-year outreach program. Thematic qualitative analyses characterized reasons for lack of follow-up with a colonoscopy after the abnormal FIT.Key resultsOf 689 patients with an abnormal FIT, 45% (n = 314) did not complete a follow-up colonoscopy. Among the 314 non-completers, 184 patients reported reasons for not completing a follow-up colonoscopy included health insurance-related challenges (38%), comorbid conditions (37%), social barriers such as transportation difficulties and lack of social support (29%), concerns about FIT/colonoscopy process (12%), competing life priorities (12%), adverse effects of bowel preparation (3%), and poor health literacy (3%). Among the 314 non-completers, 131 patients did not report a barrier, as 51% reported that that had completed a previous colonoscopy in the past 10 years, 10% refused with no reason, and 10% were never reached by phone.ConclusionsFuture studies aimed at improving FIT screening and subsequent colonoscopy rates need to address the unique needs of patients for effective and sustainable screening programs.Trial registrationNCT01946282.

Project description:BackgroundMany screening programs for colorectal cancer (CRC) use the fecal immunochemical test (FIT) to triage individuals for colonoscopy. Although these programs reduce CRC incidence and CRC-related mortality, the detection of advanced precursor lesions (advanced adenomas and advanced serrated polyps) by FIT could be improved. As an alternative for FIT, the antibody-based multitargetFIT (mtFIT) has been proposed. The mtFIT measures three protein markers: hemoglobin, calprotectin, and serpin family F member 2. In a retrospective diagnostic accuracy study in a large colonoscopy-controlled series (n = 1284), mtFIT showed increased sensitivity for advanced neoplasia (AN), at equal specificity, compared to FIT (42.9% versus 37.3%; p = 0.025). This increase was mainly due to a higher sensitivity of mtFIT for advanced adenomas (37.8% versus 28.1% for FIT; p = 0.006). The present mtFIT study aims to prospectively validate these findings in the context of the Dutch national CRC screening program.MethodThe mtFIT study is a cross-sectional intervention study with a paired design. Eligible subjects for the Dutch FIT-based national CRC screening program are invited to perform mtFIT in addition to FIT. Samples are collected at home, from the same bowel movement, and are shipped to a central laboratory by postal mail. If either one or both tests are positive, participants are referred for colonoscopy. Detailed colonoscopy and pathology data are centrally stored in a national screening database (ScreenIT; Topicus, Deventer, the Netherlands) that is managed by the screening organization, and will be retrieved for this study. We aim to determine the relative sensitivity for AN, comprising of CRC, advanced adenomas and advanced serrated polyps, of mtFIT compared to FIT at an equal positivity rate. Additionally, we will use the Adenoma and Serrated Pathway to Colorectal CAncer model to predict lifetime health effects and costs for programmatic mtFIT- versus FIT-based screening. The target sample size is 13,131 participants.DiscussionThe outcome of this study will inform on the comparative clinical utility of mtFIT versus FIT in the Dutch national CRC screening program and is an important step forward in the development of a new non-invasive stool test for CRC screening.Trial registrationClinicaltrials.gov ; NCT05314309, registered April 6th 2022, first inclusions March 25th 2022 https://clinicaltrials.gov/ct2/results?cond=&term=NCT05314309&cntry=&state=&city=&dist =.

Project description:ImportanceThe potential role of the fecal immunochemical test (FIT) for screening patients at increased risk for colorectal cancer (CRC) has not yet been elucidated.ObjectiveTo assess the diagnostic accuracy of FIT for CRC or advanced neoplasia (AN) in asymptomatic patients at above-average risk.Data sourcesMEDLINE, EMBASE, Cochrane Library, and gray literature sources through August 2016.Study selectionDiagnostic studies evaluating the accuracy of FIT for CRC or AN in patients with a personal or familial history of CRC using colonoscopy as the reference standard.Data extraction and synthesisTwo authors (A.K. and P.P.) independently extracted data and evaluated study quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, and evaluated the quality of the body of evidence by means of GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Hierarchical models were used to synthesize available evidence.Main outcomes and measuresThe primary outcome was the diagnostic performance of FIT for detecting CRC or AN.ResultsWe included 12 studies (6204 participants). Seven studies were deemed at high or unclear risk of bias. The average sensitivity of FIT for CRC was 93% (95% CI, 53%-99%), and the average specificity was 91% (95% CI, 89%-92%), yielding a positive likelihood ratio (LR+) of 10.30 (CI 7.7-13.9) and a negative likelihood ratio (LR-) of 0.08 (95% CI, 0.01-0.75) (GRADE: very low). The average sensitivity of FIT for AN was 48% (95% CI, 39%-57%); and the average specificity was 93% (95% CI, 91%-94%), yielding an LR+ of 6.55 (95% CI, 5.0-8.5) and an LR- of 0.57 (95% CI, 0.48-0.67) (GRADE: very low). Subgroup analyses indicated that FIT cutoff values between 15- and 25-μg/g feces provided the best combination of sensitivity and specificity for the diagnosis of CRC (93% and 94%, respectively). Quantitative and 1-sample FIT showed adequate test performance, but data on other FIT brands and multiple samples were insufficient.Conclusions and relevanceThe FIT has high overall diagnostic accuracy for CRC but moderate accuracy for AN in patients at above-average personal or familial risk. Heterogeneity and wide confidence intervals limit the trustworthiness of our findings.

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Reducing the Cut-Off Value of the Fecal Immunochemical Test for Symptomatic Patients Does Not Improve Diagnostic Performance.

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Reducing the Cut-Off Value of the Fecal Immunochemical Test for Symptomatic Patients Does Not Improve Diagnostic Performance.

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