Characteristics of Advanced Colorectal Cancer Detected by Fecal Immunochemical Test Screening in Participants with a Negative Result the Previous Year

Role of demographics in noninvasive testing for colorectal cancer screening: do targeted cut-off values improve detection?

BACKGROUND

Fecal immunochemical test (FIT) is a yearly alternative colorectal screening modality for average risk individuals unwilling or unable to undergo invasive colorectal cancer (CRC) screening due to cost and accessibility. This study aimed to determine whether FIT should be interpreted within the context of patient demographics and medical history.

METHODS

Patients >50 years old who had a FIT followed by colonoscopy within 1 year were analyzed based on age, race, BMI, social and medical comorbidities. False positive (FP) and false negative (FN) FIT results within each patient demographic and medical history variable were determined by comparing with the gold standard of colonoscopy using χ2 analysis.

RESULTS

One thousand twenty-five patients were reviewed. 21.8% of FIT results were positive. Factors which differed in positive FIT rates were age (P=0.003), smoking (P<0.001), alcohol (P=0.001), and hypertension (P<0.001). The difference in rates of FP and FN FIT outcomes among each variable underwent further subanalysis. The FP was 66.8% and the FN rate was 12.8%. Higher FN outcomes were noted in those above 70, males and smokers, though the result was only statistically significant for males (P=0.009). Females were observed to have higher FP rates (P=0.019).

CONCLUSIONS

Females had higher FP FIT rates compared to males, indicating that sex may influence FIT outcomes and should be accounted for when interpreting FIT results. This information can be utilized to identify populations at higher risk of FP or FN FIT results to target CRC screening. Additionally, recalculating the FP and FN rates for each variable may help determine new FIT targets.

Sensitivity of fecal immunochemical test and risk factors for interval colorectal cancer in a French population

BACKGROUND

Colorectal cancer (CRC) screening using fecal immunochemical testing (FIT) aims to detect pre-symptomatic colorectal lesions and reduce CRC mortality.

AIMS

The objectives of this study were to determine the FIT sensitivity for diagnosis of CRC, the impact of diagnostic circumstances on treatment and survival, and risk factors for interval cancer (IC).

METHODS

This population-based study evaluated the 2016-2017 CRC screening campaign in Finistère, France. CRCs were classified according to diagnostic circumstances: screen-detected CRC (SD-CRC), CRC with delayed diagnosis, IC after negative FIT (FIT-IC), post-colonoscopy CRC, CRC in non-responders and CRC in the excluded population.

RESULTS

This study included 909 CRCs: 248 SD-CRCs (6% of positive FIT) and 60 FIT-ICs (0.07% of negative FIT). The FIT sensitivity for CRC was 80.5% (CI95%: 76.1-84.9) at the threshold of 30 µg hemoglobin/g feces used in France. In multivariate analysis, proximal (OR:6.73) and rectal locations (OR:7.52) were associated with being diagnosed with FIT-IC rather than SD-CRC. The FIT positivity threshold maximizing the sum of sensitivity and specificity was found to be 17 µg/g, with 14 additional CRCs diagnosed compared to the current threshold.

CONCLUSIONS

Our study confirms the good sensitivity of FIT. A decrease of the FIT detection threshold could optimize sensitivity.

Microbiome Profiling from Fecal Immunochemical Test Reveals Microbial Signatures with Potential for Colorectal Cancer Screening

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer deaths worldwide. Early diagnosis of CRC, which saves lives and enables better outcomes, is generally implemented through a two-step population screening approach based on the use of Fecal Immunochemical Test (FIT) followed by colonoscopy if the test is positive. However, the FIT step has a high false positive rate, and there is a need for new predictive biomarkers to better prioritize cases for colonoscopy. Here we used 16S rRNA metabarcoding from FIT positive samples to uncover microbial taxa, taxon co-occurrence and metabolic features significantly associated with different colonoscopy outcomes, underscoring a predictive potential and revealing changes along the path from healthy tissue to carcinoma. Finally, we used machine learning to develop a two-phase classifier which reduces the current false positive rate while maximizing the inclusion of CRC and clinically relevant samples.

Follow-up outcomes in patients with negative initial colon capsule endoscopy findings

BACKGROUND

Colon capsule endoscopy (CCE), which became clinically applicable in 2006, is a simple and noninvasive procedure to evaluate colonic diseases; the accuracy of second-generation CCE, introduced in 2009, has dramatically improved. Currently, CCE is used as an alternative method for colorectal cancer screening, as well as for evaluating the mucosal lesions of inflammatory bowel disease, in cases where performing colonoscopy (CS) is difficult. However, the outcomes of CCE are uncertain.

AIM

To investigate the outcomes of Japanese patients with negative findings (no polyps or colorectal cancer) on initial CCE.

METHODS

This retrospective, single-center study was conducted at the Endoscopic Center at Aishinkai Nakae Hospital. This study included patients who underwent continuous CCE between November 2013 and August 2019, that exhibited no evidence of polyps or colorectal cancer at the initial CCE, and could be followed up using either the fecal immunochemical test (FIT), CS, or CCE. The observational period, follow-up method, presence or absence of polyps and colorectal cancer, pathological diagnosis, and number of colorectal cancer deaths were evaluated.

RESULTS

Thirty-one patients (mean age, 60.4 ± 15.6 years; range, 28–84 years; 14 men and 17 women) were enrolled in this study. The reasons for performing the first CCE were screening in 12, a positive FIT in six, lower abdominal pain in nine, diarrhea in two, and anemia in two patients. The mean total water volume at the time of examination was 3460 ± 602 mL (2250–4800 mL), and a total CS was performed in 28 patients (90%). The degree of cleanliness was excellent in 15 patients and good in 16, and no poor cases were observed. No adverse events, such as retention or capsule aspiration, were observed in any of the patients. The mean follow-up period was 3.1 ± 1.5 years (range, 0.3–5.5 years). Follow-up included FIT in nine, CS in 20, and CCE in four patients (including duplicate patients). The FIT was positive in two patients, while CS revealed five polyp lesions (three in the ascending colon, one in the transverse colon, and one in the descending colon), with sizes ranging between 2 mm and 8 mm. Histopathological findings revealed a hyperplastic polyp in one patient, and adenoma with low grade dysplasia in four patients; colorectal cancers were not recognized. In the follow-up example by CCE, polyps and colorectal cancer could not be recognized. During the follow-up period, there were no deaths due to colorectal cancer in any of the patients.

CONCLUSION

We determined the outcomes in patients with negative initial CCE findings.