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...

Background: There is little information about the fecal immunochemical test (FIT) in familial-risk colorectal cancer (CRC) screening. Objectives: The objective of this article is to investigate whether FIT diagnostic accuracy for advanced neoplasia (AN) differs between average and familial-risk (first-degree relative) patients. Methods: A total of 1317 consecutive participants (595 familial) who collected one stool sample before performing a colonoscopy as a CRC screening test were included. FIT diagnostic accuracy for AN was evaluated with Chi-square test at a 20 mg hemoglobin/g of feces cut-off value. Finally, we determined which variables were independently related to AN. Results: An AN was found in 151 (11.5%) patients. The overall accuracy was not statistically different between both cohorts for AN (88.4%, 91.7%; p ¼ 0.051). At the cut-off stablished, differences in FIT sensitivity (31.1%, 40.6%; p ¼ 0.2) or specificity (96.5%, 97.3%; p ¼ 0.1) were not statistically significant. Finally, independent variables such as sex (male) (odds ratio (OR) 2.1, 95% confidence interval (CI) 1.4-3.1), age (50-65, >65 years) (OR 2.1, 95% CI 1.1-4.3; OR 2.7, 95% CI 1.2-6.1), previous colonoscopy (OR 0.4, 95% CI 0.2-0.9) and FIT 20 mg/g feces (OR 17.7, 95% CI 10.8-29.1) were associated with AN diagnosis. Conclusions: FIT accuracy for AN detection is equivalent in average and familial-risk CRC screening cohorts.

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