Fecal immunochemical test accuracy in familial risk colorectal cancer screening

Abstract

There is little information on fecal immunochemical test (FIT) in familial risk colorectal cancer (CRC) screening. Our study assesses FIT accuracy, number needed to scope (NNS) and cost to detect a CRC and an advanced neoplasia (AN) in this setting. We performed a multicentric, prospective, double-blind study of diagnostic tests on individuals with first-degree relatives (FDRs) with CRC submitted to screening colonoscopy. Two stool samples were collected and fecal hemoglobin in the first sample (FIT1) and the highest in both samples (FITmax) were determined. Areas under the curve (AUC) for CRC and AN as well as the best FIT1 and FITmax cutoff value for CRC were determined. At this threshold, NNS and the cost per lesion detected were calculated. A total of 595 individuals were included (one FDR > 60 years, 413; two FDR or one 60 years, 182). AN and CRC were found in 64 (10.8%) and six (1%) patients, respectively. For CRC diagnosis, FIT1 AUC was 0.96 [95% confidence interval (CI): 0.95-0.98] and FITmax AUC was 0.95 (95% CI: 0.93-0.97). For AN diagnosis, FIT1 and FITmax AUC were 0.74 (95% CI: 0.66-0.82). The best cutoff point for CRC was 115. At this threshold, the NNS to detect a CRC was 5.67 and 7.67, and the cost per CRC was 1,064e and 1591.33e on FIT1 and FITmax strategies, respectively. FIT shows high accuracy to detect CRC in familial CRC screening. Performing two tests does not improve diagnostic accuracy, but increases cost and NNS to detect a lesion.Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer deaths in developed countries. 1 Several factors have been related to the risk of developing CRC. Age, sex and CRC familial history, especially if there are first-degree relatives (FDR) with CRC, are the strongest associated risk factors. 2 Furthermore, CRC risk is directly related to the number of FDRs and inversely related to the age of youngest FDRs. 3,4 Evidence on the best screening strategy in this population is limited and its quality is low. 5,6 At present, it is unclear which is the best screening strategy in individuals with a FDR with CRC. 7 Clinical practice guidelines recommend more aggressive screening than in average risk population, based on studies that have shown that endoscopic screening reduces CRC incidence and mortality in individuals with a FDR with CRC. 2,8 Screening is recommended from 40 years or 10 before the youngest proband. However, this approach has an empirical basis and no prospective controlled study has compared different screening strategies in this population. Furthermore, colonoscopy is an invasive technique that Key words: colorectal neoplasms, early detection of cancer, adenoma, occult blood, cost-benefit analysis Abbreviations: AN: advanced neoplasia; AUC: area under the curve; CI: confidence interval; CRC: colorectal cancer; FDR: first-degree relative; FIT: fecal immunochemical test; gFOBT: guaiac fecal occult blood tests; LLR: likelihood ratio; NNS: number needed to scope; NPV: negative predictive value; PPV: positi...

Diagnostic accuracy of fecal immunochemical test in average‐ and familial‐risk colorectal cancer screening

“…9,10 Second, the diagnostic accuracy of fecal immunochemical test (FIT) is high for CRC and acceptable for AN in this population. 11,12 However, no study, so far, has compared diagnostic accuracy of a quantitative FIT for AN detection between average-risk and familial-risk CRC screening settings. Finally, a randomized, controlled trial comparing FIT with colonoscopy has shown that FIT plus colonoscopy when positive has a similar efficacy as direct colonoscopy to detect AN in FDRs of patients with CRC.…”

Familial colorectal cancer screening: When and what to do?

“…In a cohort study of asymptomatic high-risk patients with a personal history of adenomas/CRC or family history of CRC, sensitivity, specificity, positive predictive value and negative predictive value of single FIT sampling were 80%, 89%, 3% and 99.9% for CRC and 28%, 91%, 24% and 92% for ADA, respectively [53] . High accuracy of FIT was confirmed in a multicenter study among FDRs of CRC patients, in which AUC was 0.96 (95%CI: 0.95-0.98) for CRC and 0.74 (95%CI: 0.66-0.82) for ADA [54] . European guidelines [37] recommend the use of FIT as test of choice for population screening, although gFOBT could be more practicable and affordable than FIT, considering the local labor costs and the mechanism of kit distribution and collection.…”

Characteristics of Adenomas Detected by Fecal Immunochemical Test in Colorectal Cancer Screening

“…First, we have limited our analysis to patients in whom adenomas were detected. We have previously analyzed FIT diagnostic accuracy for colorectal cancer and advanced neoplasia detection (7,8).…”

“…These 2 studies aimed to determine the number and the best cutoff point of FIT determinations in average and familial-risk colorectal cancer screening (7,8). A total of 1,317 individuals were recruited, and the most advanced lesion was a colorectal cancer in 9 patients, adenomas in 474 individuals, and nonneoplastic polyps in 179.…”

“…Furthermore, recently published data have shown that FIT sensitivity for detecting colorectal cancer is more than 74% in colorectal cancer screening and symptomatic patients evaluation (5)(6)(7)(8)(9)(10)(11). However, the main pitfall of FIT as a colorectal cancer screening method is that detection rate and diagnostic yield for advanced adenomas is inferior to colonoscopy (4)(5)(6).…”