Quantitative immunochemical fecal occult blood testing for colorectal adenoma detection: evaluation in the target population of screening and comparison with qualitative tests

Evaluation of combined detection of multigene mutation and SDC2/SFRP2 methylation in stool specimens for colorectal cancer early diagnosis

PURPOSE

Molecular diagnostics of colorectal cancer (CRC) can be used as an auxiliary approach for patients recommended for colonoscopy, providing more CRC supplemental diagnosis options. This study investigated whether combined detection of KRAS/BRAF/APC mutation and SDC2/SFRP2 methylation can serve as auxiliary diagnostics in clinical management.

METHODS

KRAS/BRAF/APC mutation and SDC2/SFRP2 methylation in stool samples from healthy donors, patients with CRC, advanced adenoma (AA), non-advanced adenoma (NAA), or other gastroenterological diseases were evaluated using quantitative PCR (qPCR) or methylation-specific quantitative PCR (MSP). Test accuracy was determined by evaluating the tests' sensitivity, specificity, positive/negative predictive value (PPV/NPV), or positive/negative likelihood ratio (PLR/NLR).

RESULTS

The combined fecal KRAS/BRAF/APC mutation and SFRP2/SDC2 methylation detection test achieved a sensitivity of 88.57% with a PPV of 93.64% and a PLR of 7.10 for CRC patients. In comparison, the corresponding parameters for multigene mutation were 46.67%, 92.59%, and 36.26 and 83.81%, 93.94%, and 7.47, for DNA methylation, separately. The sensitivity of the combined test, gene mutation test, and DNA methylation test approach was 75%, 28.26%, and 72.83%. Furthermore, the specificity of this approach in the NAA group was 79.49%. Meanwhile, the overall diagnostic specificity for the combined test in NAA, healthy control, and interference groups was 88.42%. In addition, the sensitivity of the combined detection method increased with the disease stage in CRC patients and elevated along with the lesion size (≥ 1 cm) in AA patients.

CONCLUSION

Combined detection of fecal KRAS/BRAF/APC mutation and SFRP2/SDC2 methylation has potential application value for the auxiliary diagnosis of CRC and AA.

Microsatellite Instability in Colorectal Cancer Liquid Biopsy-Current Updates on Its Potential in Non-Invasive Detection, Prognosis and as a Predictive Marker

Colorectal cancer (CRC) is the third most commonly-diagnosed cancer in the world and ranked second for cancer-related mortality in humans. Microsatellite instability (MSI) is an indicator for Lynch syndrome (LS), an inherited cancer predisposition, and a prognostic marker which predicts the response to immunotherapy. A recent trend in immunotherapy has transformed cancer treatment to provide medical alternatives that have not existed before. It is believed that MSI-high (MSI-H) CRC patients would benefit from immunotherapy due to their increased immune infiltration and higher neo-antigenic loads. MSI testing such as immunohistochemistry (IHC) and PCR MSI assay has historically been a tissue-based procedure that involves the testing of adequate tissue with a high concentration of cancer cells, in addition to the requirement for paired normal tissues. The invasive nature and specific prerequisite of such tests might hinder its application when surgery is not an option or when the tissues are insufficient. The application of next-generation sequencing, which is highly sensitive, in combination with liquid biopsy, therefore, presents an interesting possibility worth exploring. This review aimed to discuss the current body of evidence supporting the potential of liquid biopsy as a tool for MSI testing in CRC.

Individual and Joint Associations of Genetic Risk and Healthy Lifestyle Score with Colorectal Neoplasms Among Participants of Screening Colonoscopy

Genetic and lifestyle factors contribute to colorectal cancer risk. We investigated their individual and joint associations with various stages of colorectal carcinogenesis. We assessed associations of a polygenic risk score (PRS) and a healthy lifestyle score (HLS) with presence of nonadvanced adenomas and advanced neoplasms among 2,585 participants of screening colonoscopy from Germany. The PRS and HLS individually showed only weak associations with presence of nonadvanced adenomas; stronger associations were observed with advanced neoplasms (ORs, 95% CI, for highest vs. lowest risk tertile: PRS 2.27, 1.78-2.88; HLS 1.96, 1.53-2.51). The PRS was associated with higher odds of advanced neoplasms among carriers of any neoplasms (1.65, 1.23-2.22). Subjects in the highest risk tertile (vs. lowest tertile) of both scores had higher risks for nonadvanced adenomas (1.77, 1.09-2.86), for advanced neoplasms (3.95, 2.53-6.16) and, among carriers of any neoplasms, for advanced versus nonadvanced neoplasms (2.26, 1.31-3.92). Both scores were individually associated with increased risk of nonadvanced adenomas and, much more pronounced, advanced neoplasms. The similarly strong association in relative terms across all levels of genetic risk implies that a healthy lifestyle may be particularly beneficial in those at highest genetic risk, given that the same relative risk reduction in this group would imply a stronger absolute risk reduction. Genetic factors may be of particular relevance for the transition of nonadvanced to advanced adenomas. PREVENTION RELEVANCE: Genetic factors have strong impact on the risk of colorectal neoplasms, which may be reduced by healthy lifestyle. Similarly strong associations in relative terms across all levels of genetic risk imply that a healthy lifestyle may be beneficial due to higher absolute risk reduction in those at highest genetic risk.

DIAGNOSTIC ACCURACY OF ONE SAMPLE OR TWO SAMPLES QUANTITATIVE FECAL IMMUNOCHEMICAL TESTS FOR INTESTINAL NEOPLASIA DETECTION

BACKGROUND

Rectal bleeding is the most important symptom of intestinal neoplasia; thus, tests of occult blood detection in stools are widely used for pre neoplastic lesions and colorectal cancer (CRC) screening.

OBJECTIVE

Evaluate the accuracy of OC-Sensor quantitative test (Eiken Chemical, Tokyo, Japan) at cut-off 10 µg Hb/g feces (50 ng/mL) in a cohort of subjects that had to undergo diagnostic colonoscopy, and if more than one sample collected in consecutive days would improve the diagnostic accuracy of the test.

METHODS

Patients (mean age 56.3±9.7 years) that underwent colonoscopy prospectively randomly received one (1-sample FIT, FIT 1) or two (2-sample FIT, FIT 2) collection tubes. They collected the stool sample before starting colonoscopy preparation. Samples were analyzed by the OC-Auto Micro 80 (Eiken Chemical, Tokyo, Japan). The performance of FIT 1 and FIT 2 were compared to the colonoscopy findings.

RESULTS

Among 289 patients, CRC was diagnosed in 14 (4.8%), advanced adenoma in 37 (12.8%), early adenoma in 71 (24.6%) and no abnormalities in 141 (48.8%). For FIT 1, the sensitivity for CRC was 83.3% (95%CI 36.5-99.1%), for advanced adenoma was 24% (95%CI 10.1-45.5%), with specificity of 86.9% (95%CI 77.3-92.9%). For FIT 2, the sensitivity for CRC was 75% (95%CI 35.6-95.5%), for advanced adenoma was 50% (95%CI 22.3-77.7%), with specificity of 92.9% (95%CI 82.2-97.7%). The positive likelihood ratios were 1.8 (95%CI 0.7-4.4 for FIT 1) and 7.1 (95%CI 2.4-21.4 for FIT 2) for advanced adenoma, and 6.4 (95%CI 3.3-12.3, for FIT 1) and 10.7 (95%CI 3.8-29.8, for FIT 2) for CRC. The negative likelihood ratio were 0.9 (95%CI 0.7-1, for FIT 1) and 0.5 (95%CI 0.3-0.9, for FIT 2) for advanced adenoma, and 0.2 (0.03-1.1, for FIT 1) and 0.3 (0.08-0.9, for FIT 2) for CRC. The differences between FIT 1 and FIT 2 performances were not significant. However, the comparison of the levels of hemoglobin in feces of patients of FIT 1 and FIT 2 showed that the differences between no polyp group and advanced adenoma and CRC were significant.

CONCLUSION

The accuracy of OCR Sensor with 10 µg Hb/g feces cut-off was comparable to other reports and two-sample collection improved the detection rate of advanced adenoma, a pre neoplastic condition to prevent CRC incidence.

L1CAM, CA9, KLK6, HPN, and ALDH1A1 as Potential Serum Markers in Primary and Metastatic Colorectal Cancer Screening

BACKGROUND

Colorectal cancer (CRC) screening at the earlier stages could effectively decrease CRC-related mortality and incidence; however, accurate screening strategies are still lacking. Considerable interest has been generated in the detection of less invasive tests requiring a small sample volume with the potential to detect several cancer biomarkers simultaneously. Due to this, the ELISA-based method was undertaken in this study.

METHODS

Concentrations of neural cell adhesion molecule L1 (L1CAM), carbonic anhydrase IX (CA9), mesothelin (MSLN), midkine (MDK), hepsin (HPN), kallikrein 6 (KLK6), transglutaminase 2 (TGM2) aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), epithelial cell adhesion molecule (EpCAM), and cluster of differentiation 44 (CD44) from blood serum of 36 primary CRC and 24 metastatic CRC (mCRC) were calculated via MAGPIX® System (Luminex Corporation, USA).

RESULTS

Significantly increased concentration (p < 0.05) of three serum biomarkers (L1CAM, CA9, and HPN) were shown in mCRC when compared with primary CRC. HPN and KLK6 showed significant differences (p < 0.05) in concentration among different stages of CRC. In contrast, levels of HPN and ALDH1A1 were significantly elevated (p < 0.05) in chemotherapy-treated CRC patients as compared with nontreated ones. Conclusion: Serum biomarkers could act as a potential early CRC diagnostics test, but further additional testings are needed.

The second round of the Dutch colorectal cancer screening program: Impact of an increased fecal immunochemical test cut-off level on yield of screening

The Dutch colorectal cancer (CRC) screening program started in 2014, inviting the target population biennially to perform a fecal immunochemical test (FIT). We obtained prospectively collected data from the national screening information‐system to present the results of the second round (2016) and evaluate the impact of increasing the FIT cut‐off halfway through the first round from 15 to 47 μg Hb/g feces on outcomes in the second round. Second round screening was done with a 47 μg Hb/g feces FIT cut‐off. Participants were classified based on first round participation status as either FIT (15,47) or FIT (47,47) participants, and previous nonparticipants. In total, 348,891 (75.9%) out of 459,740 invitees participated in the second round. Participation rates were 93.4% among previous participants and 21.0% among previous non‐participants. FIT(47,47) participants had a significantly higher detection rate of AN (15.3 vs. 10.4 per 1,000 participants) compared to FIT(15,47) participants in the second round, while their cumulative detection rate of AN over two rounds was significantly lower (45.6 vs. 52.6 per 1,000 participants). Our results showed that participation in the Dutch CRC screening program was consistently high and that second round detection rates depended on the first round FIT cut‐off. The cumulative detection over two rounds was higher among FIT(15,47) participants. These findings suggest that a substantial part of, but not all the missed findings in the first round due to the increased FIT cut‐off were detected in the subsequent round.

What's new?

In 2014, the Netherlands implemented colorectal cancer (CRC) screening based on non‐invasive fecal immunochemical testing (FIT), which offers a practical approach for population‐based CRC detection. In the Dutch program's first round, to match local resources, FIT cut‐off was increased, resulting in reduced positivity rates and reduced colonoscopy referrals, at the cost of missing advanced neoplasias. The current study shows that many of these missed advanced neoplasias were detected in subsequent screening, suggesting that increased FIT cut‐off had marginal impact on screening outcome. The findings could benefit other CRC screening programs in establishing effective FIT cut‐offs.

Diagnostic Accuracy Of Fecal Occult Blood Tests For Detecting Proximal Versus Distal Colorectal Neoplasia: A Systematic Review And Meta-Analysis

Objective

We conducted a systematic review and meta-analysis aimed at evaluating the differences of diagnostic performance of fecal occult blood tests (FOBTs) in detecting advanced colorectal neoplasms located in the proximal versus distal colorectum.

Methods

PubMed, Embase, Cochrane Library, and Web of Science were searched for eligible articles published before August 17, 2018. Two independent reviewers conducted study assessment and data extraction. Diagnosis-related indicators of FOBT for detecting proximal and distal colorectal neoplasms were summarized, and further stratified by the type of FOBT (guaiac-based FOBT (gFOBT) and immunochemical FOBT (iFOBT)). Pooled sensitivities and specificities were calculated using a random effect model. Summary receiver operating characteristic curves were plotted and area under the curves were calculated.

Results

Overall, 31 studies meeting the inclusion criteria were included in this review. For gFOBT, we found no site-specific difference (proximally vs distally located) of pooled sensitivities observed in the colorectal cancer (CRC), advanced adenomas, and advanced neoplasms groups. As for iFOBT, pooled sensitivities for detecting CRC located in the distal colon/rectum were comparable with that in the proximal colon (proximal vs distal, 0.67, 95% CI 0.62-0.72 vs 0.72, 95% CI 0.68-0.75), while higher pooled sensitivities for detecting advanced adenomas and advanced neoplasms located in the distal colon/rectum than for detecting those in the proximal colon were observed for iFOBT with the values of 0.24 (95% CI 0.22-0.25) vs 0.32 (95% CI 0.30-0.34) and 0.25 (95% CI 0.23-0.28) vs 0.38 (95% CI 0.36-0.40), respectively. Summary receiver operating characteristic curve analyses showed similar patterns for both types of FOBT regarding the diagnostic accuracy for detecting colorectal neoplasms according to the anatomical sites of the colorectum.

Conclusion

iFOBT had higher sensitivity for detecting advanced adenomas and advanced neoplasia located in the distal colon/rectum than that for those in the proximal colon.

[Current evidence and development of colorectal cancer screening in Germany]

Colon cancer is currently the third leading cause of cancer death in men and women in Germany, with a total of about 25,000 deaths per year. Established methods for early detection of colorectal cancer include lower gastrointestinal endoscopy and fecal occult blood testing. For both procedures, there is evidence of a reduction in colorectal cancer-specific mortality and for endoscopy a reduction of colorectal cancer incidence has been shown.In Germany, the guaiac test for fecal occult blood has been offered since 1977. Additionally, screening colonoscopy has been offered since 2002 and in 2016, the guaiac test was replaced by the immunological fecal occult blood test, which has an improved diagnostic performance. Overall, participation rates have been low over the past decades and differed between men, women, and age groups.Personal invitations are expected to be sent out starting in 2019 as part of the introduction of an organized colorectal cancer screening program in Germany. The program also provides for measures to systematically monitor and improve the quality of colorectal cancer screening. It remains to be seen which effects these changes will have and whether the trend towards declining colon cancer incidence and mortality that has been observed in Germany will continue in the coming years.

Fibroblast growth factor 21 as a circulating biomarker at various stages of colorectal carcinogenesis

Background

Despite evidence that inflammation and metabolism play a crucial role in colorectal carcinogenesis, there have been few studies on the association of inflammatory and metabolic protein biomarkers in various stages of colorectal carcinogenesis.

Methods

Ninety-two inflammatory and metabolic biomarkers were measured in plasma samples of participants of screening colonoscopy. Markers identified to be significantly associated with the presence of advanced colorectal neoplasia (ACN) in a discovery set (n = 204) were validated in an independent replication set (n = 422). Adjusted associations with the presence of non-advanced adenomas (NAA), advanced precancerous lesions (APL) and colorectal cancer (CRC) were quantified by multiple logistic regression.

Results

Out of the 92 inflammatory proteins, 72 markers were evaluable and 8 showed statistically significant associations with the odds of ACN after full adjustment for potential risk factors for CRC in the discovery set. One of these, fibroblast growth factor 21 (FGF-21), could be validated in the replication set. The multivariable-adjusted odds ratio (OR) reached 2.65 (95% CI, 1.50–4.81) for individuals with FGF-21 levels within the highest tertile, compared to those within the lowest tertile (P_trend across tertiles = 0.001). Separate models revealed fully adjusted ORs for NAA, APL and CRC of 2.99 (95% CI, 1.45–6.58, P_trend = 0.005), 2.24 (95% CI, 1.18–4.44, P_trend = 0.021) and 3.92 (95% CI, 1.51–12.18, P_trend = 0.003), respectively.

Conclusions

Circulating FGF-21 level is associated with increased risk of early and late stages of colorectal carcinogenesis, supporting a role of inflammation and metabolism at all stages of colorectal carcinogenesis, and suggesting potential use of this biomarker for risk stratification in CRC screening.

Diagnostic Performance of Intestinal Fusobacterium nucleatum in Colorectal Cancer: A Meta-Analysis

Background:

Increasing evidence has supported the link of intestinal Fusobacterium nucleatum infection to colorectal cancer (CRC). However, the value of F. nucleatum as a biomarker in CRC detection has not been fully defined. In order to reduce the random error and bias of individual research, this meta-analysis aimed to evaluate the diagnostic performance of intestinal F. nucleatum in CRC patients and provide evidence-based data to clinical practice.

Methods:

An article search was performed from PubMed, Embase, Cochrane Library, and Web of Science databases up to December 2017, using the following key words: “Fusobacterium nucleatum”, ”Fusobacterium spp.”, ”Fn”, “colorectal cancer(s)”, “colorectal carcinoma(s)”, “colorectal neoplasm(s)”, and “colorectal tumor(s)”. Articles on relationships between F. nucleatum and CRC were selected according to the preestablished inclusion and exclusion criteria. This meta-analysis was performed using STATA 12.0 software, which included mapping of forest plots, heterogeneity tests, meta-regression, subgroup analysis, sensitivity analysis, and publication bias. The sensitivity, specificity, positive likelihood ratio (LR), negative LR, diagnostic odds ratio (DOR), and their corresponding 95% confidence interval (CI) of each eligible study were summarized.

Results:

Finally, data for 1198 participants (629 CRC and 569 healthy controls) in 10 controlled studies from seven articles were included. The summary receiver operator characteristic curve was mapped. The diagnostic performance of intestinal F. nucleatum infection on CRC was as follows: the area under the curve: 0.86 (95% CI: 0.83–0.89), the pooled sensitivity: 0.81 (95% CI: 0.64–0.91), specificity: 0.77 (95% CI: 0.59–0.89), and DOR: 14.00 (95% CI: 9.00–22.00).

Conclusion:

Intestinal F. nucleatum is a valuable marker for CRC diagnosis.

Fecal immunochemical test for hemoglobin in combination with fecal transferrin in colorectal cancer screening

Objective

Fecal transferrin has been suggested as a complementary or even superior marker for early detection of colorectal cancer (CRC) besides fecal hemoglobin. We aimed to evaluate both markers individually and in combination in a large cohort of participants of screening colonoscopy.

Methods

Precolonoscopy stool samples were obtained from participants of screening colonoscopy and frozen at -80℃ until blinded analysis, using a dual-quantitative fecal immunochemical test (FIT) for hemoglobin and transferrin. Sensitivity, specificity and area under the curve (AUC) were calculated for CRC and advanced adenoma (AA).

Results

A total of 1667 participants fulfilled our inclusion criteria. All individuals with advanced neoplasm (AN) (16 CRC, 200 AA) and 300 randomly selected participants without AN were included. Mean age was 63 years and 56% were male. The AUC for CRC and AA was 92% and 68%, respectively, for hemoglobin vs. 79% and 58%, respectively for transferrin. Combination of both markers yielded an AUC for CRC and AA of 92% and 68%, respectively.

Conclusion

FIT for hemoglobin shows better diagnostic performance than FIT for transferrin for the detection of ANs (both proximal and distal neoplasms), and a combination of both markers does not improve the diagnostic performance.

Clinical applications of gut microbiota in cancer biology

The involvement of microorganisms in cancer has been increasing recognized. Collectively, microorganisms have been estimated to account for ∼20% of all cancers worldwide. Recent advances in metagenomics and bioinformatics have provided new insights on the microbial ecology in different tumors, pinpointing the roles of microorganisms in cancer formation, development and response to treatments. Furthermore, studies have emphasized the importance of host-microbial and inter-microbial interactions in the cancer microbiota. These studies have not only revolutionized our understanding of cancer biology, but also opened up new opportunities for cancer prevention, diagnosis, prognostication and treatment. This review article aims to summarize the microbiota in various cancers and their treatments, and explore clinical applications for such relevance.

Variation of diagnostic performance of fecal immunochemical testing for hemoglobin by sex and age: results from a large screening cohort

Objective

Fecal immunochemical tests (FITs) for hemoglobin in stool are increasingly used for colorectal cancer screening. Reported sensitivities and specificities have strongly varied between studies, but it is unclear to what extent such variation reflects differences between tests or between study population characteristics. We aimed to evaluate the key parameters of FIT performance for detecting advanced neoplasia (AN) according to sex and age.

Methods

Sex- and age-specific sensitivity, specificity, positive predictive values (PPVs) and negative predictive values (NPVs) for detecting AN of a quantitative FIT (FOB Gold®) were evaluated among 3211 men and women aged 50–79 years who underwent screening colonoscopy in Germany.

Results

At the cutoff recommended by the manufacturer (17 µg hemoglobin/g feces), sensitivity was higher (51.2% versus 34.7%, p=0.004) and specificity was lower (91.0% versus 94.8%, p<0.001) among 65–79 year-old participants compared with 50–64 year-old participants. PPVs and NPVs did not differ significantly between age groups. However, higher NPVs were observed among women compared with men (94.7% versus 92.5%, p=0.015). Specificity was also higher among women compared with men (94.7% versus 92.3%, p=0.007), while there was only a little variation in sensitivity (40.3% versus 41.8%, p=0.789) according to sex. In joint stratification by both factors, sensitivity ranged from 34.1% (95% CI 24.2%–45.2%) in 50–64 year-old women to 51.4% (95% CI 39.3%–63.3%) in 65–79 year-old men (p=0.029). The observed age and sex differences were highly consistent across a wide range of alternative cutoffs from 10 to 50 µg hemoglobin/g feces.

Conclusion

There are major differences in diagnostic performance parameters according to sex and age, which should receive careful attention in the interpretation and comparison of results of FIT-based colorectal cancer screening studies.

Overall evaluation of an immunological latex agglutination system for fecal occult blood testing in the colorectal cancer screening program of Florence

Several immunological fecal occult blood tests (FOBT) are currently available for colorectal cancer (CRC) screening. We compared the HM Jack (Jack) (Kiowa, Japan), with the OC-Hemodia (OC) (Eiken, Japan) in use in the Florence screening program. Aims of the study were: (i) to investigate the diagnostic performance and the best cutoff value for Jack; (ii) to evaluate the handiness of sampling tubes; (iii) to compare costs. A total of 5,044 subjects were screened with both tests. Sampling tube investigation was performed running each sample on both instruments. A number of 352 subjects positive for at least one test (175 OC, 310 Jack) were selected for further investigations, while 46 subjects refused further assessments. Analysis of costs related to the assessment phase was performed on the basis of Tuscany region's fares. Amongst the 306 subjects investigated, 9 CRC and 67 advanced adenomas (AdA) were detected. Detection rates (DR) were 1.4‰ for CRC and 9.6‰ for AdA. After Jack cutoff optimization, DR for CRC+AdA resulted in 11.1‰ for OC and 13.3‰ for Jack (p=0.041). Sensitivity of the methods was 73.7 for OC and 88.2 for Jack; specificity was 97.6 for OC and 96.0 for Jack, resulting in an increase of the required assessments from 3.5% to 5.1%. No differences were observed between sampling methods. Despite the lower specificity of Jack, its greater sensitivity makes the method attractive for screening programs. An increase of the costs of 30% for every subject investigated for pathological lesion (CRC+AdA) may be thus foreseen.

Quantitative fecal immunochemical tests for colorectal cancer screening

Fecal immunochemical tests (FITs) for hemoglobin (Hb) are increasingly used for colorectal cancer (CRC) screening. We aimed to review, summarize and compare reported diagnostic performance of various FITs. PubMed and Web of Science were searched from inception to July 24, 2017. Data on diagnostic performance of quantitative FITs, conducted in colonoscopy-controlled average-risk screening populations, were extracted. Summary receiver operating characteristic (ROC) curves were plotted and correlations between thresholds, positivity rates (PRs), sensitivities and specificities were assessed. Seven test brands were investigated across 22 studies. Although reported sensitivities for CRC, advanced adenoma (AA) and any advanced neoplasm (AN) varied widely (ranges: 25-100%, 6-44% and 9-60%, respectively), with specificities for AN ranging from 82% to 99%, the estimates were very close to the respective summary ROC curves whose areas under the curve (95% CI) were 0.905 (0.88-0.94), 0.683 (0.67-0.70) and 0.710 (0.70-0.72) for CRC, AA and AN, respectively. The seemingly large heterogeneity essentially reflected variations in test thresholds (range: 2-82 µg Hb/g feces) and showed moderate correlations with sensitivity (r = -0.49) and specificity (r = 0.60) for AN. By contrast, observed PRs (range: 1-21%) almost perfectly correlated with sensitivity (r = 0.84) and specificity (r = -0.94) for AN. The apparent large heterogeneity in diagnostic performance between various FITs can be almost completely overcome by appropriate threshold adjustments. Instead of simply applying the threshold recommended by the manufacturer, screening programs should adjust the threshold to yield a desired PR which is a very good proxy indicator for the specificity and the subsequent colonoscopy workload.

Blood-Based Protein Signatures for Early Detection of Colorectal Cancer: A Systematic Review

OBJECTIVES

Blood-based proteins might be an attractive option for early detection of colorectal cancer (CRC), but individually they are unlikely to achieve the diagnostic performance required for population based screening. We aimed at summarizing current evidence of diagnostic performance of signatures based on multiple proteins for early detection of CRC.

METHODS

A systematic literature review adhering to the PRISMA (preferred reporting items for systematic reviews and meta-analysis) guidelines was performed. PubMed and Web of Science databases were searched for potentially relevant studies published until 28th August, 2017. Relevant studies were identified by predefined eligibility criteria. Estimates of indicators of diagnostic performance such as sensitivity, specificity, and the area under the curve (AUC), along with information on validation and other key methodological procedures were extracted. Study quality was assessed by a QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) instrument tool.

RESULTS

Thirty six eligible studies with numbers of CRC cases ranging from 23 to 512 and the number of proteins included in signatures ranged from 3 to 13 were identified. Reported Youden's Index and AUC ranged from 0.19 to 0.95 and from 0.62 to 0.996, respectively. However most studies, especially those reporting better diagnostic performance, were conducted in clinical rather than screening setting and many studies lacked any internal or external validation of identified algorithm.

CONCLUSIONS

Blood-based tests using signatures of multiple proteins may be a promising approach for non-invasive CRC screening. However, promising signatures identified in clinical settings still require rigorous evaluation in large studies conducted in true screening setting.

Fresh vs Frozen Samples and Ambient Temperature Have Little Effect on Detection of Colorectal Cancer or Adenomas by a Fecal Immunochemical Test in a Colorectal Cancer Screening Cohort in Germany

BACKGROUND & AIMS

Fecal immunochemical tests (FITs) are used in colorectal cancer (CRC) screening. We compared detection of CRCs and colorectal neoplasms by FITs using fresh samples (collected into buffer-filled tubes) vs frozen samples, and we assessed the effects of seasonal variations in ambient temperature on test performance.

METHODS

We performed a prospective study of 3466 individuals (50% male; mean age, 62 years) undergoing screening colonoscopies at 20 gastroenterology practices in southern Germany from November 2008 through September 2014. Frozen stool samples (collected and frozen by patients through February 2012, n = 1644) and fresh stool samples (collected by patients into buffer-filled tubes after February 2012, n = 1822) were obtained; hemoglobin (Hgb) concentrations were measured by using a commercial, quantitative FIT (cutoff value for positive result, 17 μg Hgb/g feces). Colonoscopy results were used as the gold standard, with results categorized as CRC, advanced adenoma, non-advanced adenoma, or no colorectal neoplasm. Differences in detection of colorectal neoplasms with fresh vs frozen samples were compared by using Wilcoxon rank sum test (continuous variables) and Fisher exact test (categorical variables). We also compared test performance when samples were collected during different seasons (based on outdoor temperature less than 8°, 8°-15°, or more than 15°).

RESULTS

Of the samples analyzed by FIT, 12.8% of frozen stool samples (95% confidence interval [CI], 11.3%-14.5%) and 8.7% of fresh stool samples (95% CI, 7.5%-10.1%) had positive results (P value for difference < .001). When adjusting the Hgb cutoff value to produce the same percentage of positive results for fresh and frozen samples (10% and 5%), FIT with frozen vs fresh samples detected colorectal neoplasms with similar levels of sensitivity and specificity. For example, at cutoff values that produced 5% positive results for each sample type, FIT detected advanced neoplasms with 27.8% sensitivity when frozen samples were used (95% CI, 21.4%-35.1%) and 25.6% sensitivity when fresh samples were used (95% CI, 19.8%-32.1%). Specificity values were 97.7% when frozen samples were used (95% CI, 96.8%-98.4%) and 97.6% when fresh samples were used (95% CI, 96.7%-98.3%). We did not observe any differences in detection of neoplasms during different seasons that were based on outdoor temperature.

CONCLUSIONS

In a prospective study of 3466 individuals who underwent screening colonoscopies and received FITs, we found that use of fresh vs frozen samples slightly affected positivity rates and the proportions of CRCs or adenomas detected at the recommended Hgb cutoff value. However, after we adjusted Hgb cutoff values to produce equal proportions of positive results for fresh vs frozen samples, the performance of the FIT was similar with each sample type. Season of sample collection (based on outdoor temperature) did not affect detection of CRC using either sample type in this study from Middle Europe.

Selecting a Cut-off for Colorectal Cancer Screening With a Fecal Immunochemical Test

OBJECTIVES

Fecal immunochemical tests (FITs) for hemoglobin (Hb) are increasingly used for colorectal cancer (CRC) screening. However, cut-offs for defining test positivity are varying widely. We aimed to evaluate the impact of cut-off selection on key indicators of diagnostic performance in a true screening setting.

METHODS

We evaluated diagnostic performance of FOB Gold, a widely used quantitative FIT, for detecting advanced neoplasms (AN) across a wide range of possible cut-offs among 1822 participants of screening colonoscopy aged 50-79 years in Germany.

RESULTS

The positive predictive value (PPV) for detecting AN showed a very steep increase with increasing cut-off up to 35.2% (95% CI 29.9-40.9%) at a cut-off of 9 μg Hb/g feces at which sensitivity and specificity were 48.8% (95% CI 42.1-55.6%) and 88.5% (95% CI 86.8-89.9%), respectively. A further moderate increase of PPV up to 56.9% (95% CI 47.8-65.5%), along with a major decrease in sensitivity was observed when gradually increasing the cut-off to 25 μg Hb/g feces at which sensitivity and specificity were 31.9% (95% CI 25.9-38.5%) and 96.9% (95% CI 95.9-97.6%), respectively. Further increases of the cut-off hardly affected PPV and specificity, but went along with further relevant decline in sensitivity.

CONCLUSIONS

Our study illustrates delineation of a range of meaningful cut-offs (here: 9-25 μg Hb/g feces) according to expected diagnostic yield in a true screening setting. Selecting a cut-off within or beyond this range should consider characteristics of the specific target population, such as AN prevalence or available colonoscopy capacity.

Quantitation of faecal Fusobacterium improves faecal immunochemical test in detecting advanced colorectal neoplasia

OBJECTIVE

There is a need for an improved biomarker for colorectal cancer (CRC) and advanced adenoma. We evaluated faecal microbial markers for clinical use in detecting CRC and advanced adenoma.

DESIGN

We measured relative abundance of Fusobacterium nucleatum (Fn), Peptostreptococcus anaerobius (Pa) and Parvimonas micra (Pm) by quantitative PCR in 309 subjects, including 104 patients with CRC, 103 patients with advanced adenoma and 102 controls. We evaluated the diagnostic performance of these biomarkers with respect to faecal immunochemical test (FIT), and validated the results in an independent cohort of 181 subjects.

RESULTS

The abundance was higher for all three individual markers in patients with CRC than controls (p<0.001), and for marker Fn in patients with advanced adenoma than controls (p=0.022). The marker Fn, when combined with FIT, showed superior sensitivity (92.3% vs 73.1%, p<0.001) and area under the receiver-operating characteristic curve (AUC) (0.95 vs 0.86, p<0.001) than stand-alone FIT in detecting CRC in the same patient cohort. This combined test also increased the sensitivity (38.6% vs 15.5%, p<0.001) and AUC (0.65 vs 0.57, p=0.007) for detecting advanced adenoma. The performance gain for both CRC and advanced adenoma was confirmed in the validation cohort (p=0.0014 and p=0.031, respectively).

CONCLUSIONS

This study identified marker Fn as a valuable marker to improve diagnostic performance of FIT, providing a complementary role to detect lesions missed by FIT alone. This simple approach may improve the clinical utility of the current FIT, and takes one step further towards a non-invasive, potentially more accurate and affordable diagnosis of advanced colorectal neoplasia.

Immunochemical faecal occult blood testing to screen for colorectal cancer: can the screening interval be extended?

OBJECTIVE

Colorectal cancer (CRC) screening programmes based on faecal immunochemical testing for haemoglobin (FIT) typically use a screening interval of 2 years. We aimed to estimate how alternative FIT strategies that use a lower than usual positivity threshold followed by a longer screening interval compare with conventional strategies.

METHODS

We analysed longitudinal data of 4523 Dutch individuals (50-74 years at baseline) participating in round I of a one-sample FIT screening programme, of which 3427 individuals also participated in round II after 1-3 years. The cohort was followed until 2 years after round II. In both rounds, a cut-off level of ≥50 ng haemoglobin (Hb)/mL buffer (corresponding to 10 µg Hb/g faeces) was used, representing the standard scenario. We determined the cumulative positivity rate (PR) and the numbers of subjects diagnosed with advanced adenomas (N_AdvAd) and early stage CRC (N_earlyCRC) in the cohort over two rounds of screening (standard scenario) and compared it with hypothetical single-round screening with use of a lower cut-off and omission of the second round (alternative scenario).

RESULTS

In the standard scenario, the cumulative (ie, round I and II combined) PR, N_AdvAd and N_earlyCRC were 13%, 180% and 26%, respectively. In alternative scenarios using a cut-off level of respectively ≥11 and ≥22 ng/HbmL buffer (corresponding to 2 and 4 µg Hb/g faeces), the PRs were 18% and 13%, the N_AdvAd were 180 and 162 and the N_earlyCRC ranged between 22-27 and 22-26.

CONCLUSIONS

The diagnostic yield of FIT screening using a lowered positivity threshold in combination with an extended screening interval (up to 5 years) may be similar to conventional FIT strategies. This justifies and motivates further research steps in this direction.

Which Fecal Immunochemical Test Should I Choose?

OBJECTIVES

To summarize the fecal immunochemical tests (FITs) available in the United States, the 2014 pathology proficiency testing (PT) program FIT results, and the literature related to the test characteristics of FITs available in the United States to detect advanced adenomatous polyps (AAP) and/or colorectal cancer (CRC).

METHODS

Detailed review of the Food and Drug Administration's Clinical Laboratory Improvement Amendments (CLIA) database of fecal occult blood tests, the 2014 FIT PT program results, and the literature related to FIT accuracy.

RESULTS

A search of the CLIA database identified 65 FITs, with 26 FITs available for purchase in the United States. Thirteen of these FITs were evaluated on a regular basis by PT programs, with an overall sensitivity of 99.1% and specificity of 99.2% for samples spiked with hemoglobin. Automated FITs had better sensitivity and specificity than CLIA-waived FITs for detection of AAP and CRC in human studies using colonoscopy as the gold standard.

CONCLUSION

Although many FITs are available in the United States, few have been tested in proficiency testing programs. Even fewer have data in humans on sensitivity and specificity for AAP or CRC. Our review indicates that automated FITs have the best test characteristics for AAP and CRC.

Recommendations on Fecal Immunochemical Testing to Screen for Colorectal Neoplasia: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer

The use of the fecal occult blood test (FOBT) for colorectal cancer (CRC) screening is supported by randomized trials demonstrating effectiveness in cancer prevention and widely recommended by guidelines for this purpose. The fecal immunochemical test (FIT), as a direct measure of human hemoglobin in stool has a number of advantages relative to conventional FOBT and is increasingly used relative to that test. This review summarizes current evidence for FIT in colorectal neoplasia detection and the comparative effectiveness of FIT relative to other commonly used CRC screening modalities. Based on evidence, guidance statements on FIT application were developed and quality metrics for program implementation proposed.

The Optimal Cut-Off Level of The Fecal Immunochemical Test For Colorectal Cancer Screening in a Country with Limited Colonoscopy Resources: A Multi-Center Study from Thailand

Background:

Selecting the cut-off point for the fecal immunochemical test (FIT) for colorectal cancer (CRC) screening programs is of prime importance. The balance between the test performance for detecting advanced neoplasia and the available colonoscopy resources should be considered. We aimed to identify the optimal cut-off of FIT for advanced neoplasia in order to minimize colonoscopy burden.

Methods:

We conducted a multi-center study in 6 hospitals from diverse regions of Thailand. Asymptomatic participants, aged 50-75 years, were tested with one-time quantitative FIT (OC-SENSOR, Eiken Chemical Co.,Ltd., Tokyo, Japan) and all participants underwent colonoscopy. We assessed test performance in detecting advanced neoplasia (advanced adenoma and CRC) and measured the burden of colonoscopy with different cut-offs [25 (FIT25), 50 (FIT50), 100 (FIT100), 150 (FIT150), and 200 (FIT200)ng/ml].

Results:

Among 1,479 participants, advanced neoplasia and CRC were found in 137 (9.3%) and 14 (0.9%), respectively. From FIT25 to FIT200, the positivity rate decreased from 18% to 4.9%. For advanced neoplasia, an increased cut-off decreased sensitivity from 42.3% to 16.8% but increased specificity from 84.2% to 96.3%. The increased cut-off increased the positive predictive value (PPV) from 21.5% to 31.5%. However, all cut-off points provided a high negative predictive value (NPV) (>90%). For CRC, the miss rate for FIT25 to FIT 150 was the same (n=3, 21%), whereas that with FIT200 increased to 35% (n=5).

Conclusions:

In a country with limited-colonoscopy resources, using FIT150 may be preferred because it offers both high PPV and NPV for advanced neoplasia detection. It could also decrease colonoscopy workload, while maintaining a CRC miss rate similar to those with lower cut-offs.

Recommendations on Fecal Immunochemical Testing to Screen for Colorectal Neoplasia: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer

The use of the fecal occult blood test (FOBT) for colorectal cancer (CRC) screening is supported by randomized trials demonstrating effectiveness in cancer prevention and widely recommended by guidelines for this purpose. The fecal immunochemical test (FIT), as a direct measure of human hemoglobin in stool has a number of advantages relative to conventional FOBT and is increasingly used relative to that test. This review summarizes current evidence for FIT in colorectal neoplasia detection and the comparative effectiveness of FIT relative to other commonly used CRC screening modalities. Based on evidence, guidance statements on FIT application were developed and quality metrics for program implementation proposed.

The Effect of Educational Intervention on the Patient's Willingness to Carry out the Immunochemical Faecal Occult Blood Test for Colorectal Cancer

Background

There is now compelling evidence that screening for colorectal cancer may result in significantly reduced mortality. Screening tests for colorectal cancer are not systematically performed in Bulgaria.

Aim

This article explores the effect of an educational intervention on the willingness of patients to participate in the screening for colorectal cancer with the immunochemical faecal occult blood test in the home setting.

Materials and methods

A before-after design study of the effects of educational intervention comprising distribution of a brochure and one-to-one discussion with a GP. A self-administered, original questionnaire was administered before and after the intervention to 600 randomly selected patients in 40 general practices (15 patients per practice) in Plovdiv district.

Results

The intervention led to an increase with >20% of the patient’s knowledge of the importance of the test and on how to carry out the test. Statistical analysis indicated that there was an increase in knowledge after the educational intervention about the usefulness of the test (24.8% in males, 18.3% in females) and its performance (22.7% in males, 25.4% in females).

Conclusion

The educational intervention has significantly influenced the patient’s awareness about the test’s usefulness and its self-administration. It improved the awareness by providing an easy access to information, thus fostering the active involvement of the patients. A strength of the intervention was the patient-centered approach in providing additional information through one-to-one discussions, and it ensured a higher quality of the preventive screening in the general practice.

Evaluation of the diagnostic value of 64 simultaneously measured autoantibodies for early detection of gastric cancer

Autoantibodies against tumor-associated antigens (TAAs) have been suggested as biomarkers for early detection of gastric cancer. However, studies that systematically assess the diagnostic performance of a large number of autoantibodies are rare. Here, we used bead-based multiplex serology to simultaneously measure autoantibody responses against 64 candidate TAAs in serum samples from 329 gastric cancer patients, 321 healthy controls and 124 participants with other diseases of the upper digestive tract. At 98% specificity, sensitivities for the 64 tested autoantibodies ranged from 0–12% in the training set and a combination of autoantibodies against five TAAs (MAGEA4 + CTAG1 + TP53 + ERBB2_C + SDCCAG8) was able to detect 32% of the gastric cancer patients at a specificity of 87% in the validation set. Sensitivities for early and late stage gastric cancers were similar, while chronic atrophic gastritis, a precursor lesion of gastric cancer, was not detectable. However, the 5-marker combination also detected 26% of the esophageal cancer patients. In conclusion, the tested autoantibodies and combinations alone did not reach sufficient sensitivity for gastric cancer screening. Nevertheless, some autoantibodies, such as anti-MAGEA4, anti-CTAG1 or anti-TP53 and their combinations could possibly contribute to the development of cancer early detection tests (not necessarily restricted to gastric cancer) when being combined with other markers.

A pilot study on faecal MMP-9: a new noninvasive diagnostic marker of colorectal cancer

Background:

Colorectal cancer (CRC) is one of the leading malignancies worldwide, therefore cheap noninvasive screening methods are of great importance. Matrix-metalloproteinase-9 (MMP-9) has a role in the progression of CRC, and its level is elevated in tumour biopsies. Faecal MMP-9 levels are increased in active ulcerative colitis patients, but in CRC patients, they have never been measured. We aimed to assess the faecal MMP-9 levels in patients undergoing total colonoscopy according to endoscopic and histological diagnosis.

Methods:

One hundred and nine patients provided faecal samples for MMP-9 analysis. A total colonoscopy was performed; suspicious lesions were evaluated by histology. Faecal MMP-9 levels were measured by ELISA.

Results:

The number of patients allocated to different groups were: negative/diverticulosis: 34 (referred to as controls); hyperplastic polyps: 15; adenomas: 32 (22 at high risk); and CRC: 28. Faecal MMP-9 was significantly increased in CRC compared with all other groups (P<0.001). Faecal MMP-9 was suitable to distinguish CRC patients from controls (sensitivity: 89.3% specificity: 91.2%). By means of a lower cutoff level, faecal MMP-9 identified high-risk adenomas besides CRC (sensitivity: 76% specificity: 85.3%). This lower cutoff level screened 59% of high-risk adenomas.

Conclusions:

Faecal MMP-9 may be a promising new noninvasive marker in CRC.

Colorectal Cancer Screening Programme in Spain: Results of Key Performance Indicators After Five Rounds (2000-2012)

Effective quality assurance is essential in any screening programme. This article provides a unique insight into key quality indicators of five rounds of the first population-based colorectal cancer screening programme implemented in Spain (2000–2012), providing the results according to the type of screening (prevalent or first screen and incident or subsequent screen) and test (guaiac or immunochemical). The total crude participation rate increased from 17.2% (11,011) in the first round to 35.9% (22,988) in the last one. Rescreening rate was very high (88.6% in the fifth round). Positivity rate was superior with the faecal immunochemical test (6.2%) than with the guaiac-based test (0.7%) (p < 0.0001) and detection rates were also better with the immunochemical test. The most significant rise in detection rate was observed for high risk adenoma in men (45.5 per 1,000 screened). Most cancers were diagnosed at an early stage (61.4%) and there was a statistically significant difference between those detected in first or subsequent screening (52.6% and 70.0% respectively; p = 0.024). The availability of these results substantially improves data comparisons and the exchange of experience between screening programmes.

Evaluation of a 5-Marker Blood Test for Colorectal Cancer Early Detection in a Colorectal Cancer Screening Setting

PURPOSE

In initial studies that included colorectal cancer patients undergoing diagnostic colonoscopy, we had identified a serum marker combination able to detect colorectal cancer with similar diagnostic performance as fecal immunochemical test (FIT). In this study, we aimed to validate the results in participants of a large colorectal cancer screening study conducted in the average-risk, asymptomatic screening population.

EXPERIMENTAL DESIGN

We tested serum samples from 1,200 controls, 420 advanced adenoma patients, 4 carcinoma in situ patients, and 36 colorectal cancer patients with a 5-marker blood test [carcinoembryonic antigen (CEA)+anti-p53+osteopontin+seprase+ferritin]. The diagnostic performance of individual markers and marker combinations was assessed and compared with stool test results.

RESULTS

AUCs for the detection of colorectal cancer and advanced adenomas with the 5-marker blood test were 0.78 [95% confidence interval (CI), 0.68-0.87] and 0.56 (95% CI, 0.53-0.59), respectively, which now is comparable with guaiac-based fecal occult blood test (gFOBT) but inferior to FIT. With cutoffs yielding specificities of 80%, 90%, and 95%, the sensitivities for the detection of colorectal cancer were 64%, 50%, and 42%, and early-stage cancers were detected as well as late-stage cancers. For osteopontin, seprase, and ferritin, the diagnostic performance in the screening setting was reduced compared with previous studies in diagnostic settings while CEA and anti-p53 showed similar diagnostic performance in both settings.

CONCLUSIONS

Performance of the 5-marker blood test under screening conditions is inferior to FIT even though it is still comparable with the performance of gFOBT. CEA and anti-p53 could contribute to the development of a multiple marker blood-based test for early detection of colorectal cancer.

Development of new non-invasive tests for colorectal cancer screening: the relevance of information on adenoma detection

Researchers are actively pursuing the development of a new non-invasive test (NIT) for colorectal cancer (CRC) screening as an alternative to fecal occult blood tests (FOBTs). The majority of pilot studies focus on the detection of invasive CRC rather than precursor lesions (i.e., adenomas). We aimed to explore the relevance of adenoma detection for the viability of an NIT for CRC screening by considering a hypothetical test that does not detect adenomas beyond chance. We used the Simulation Model of Colorectal Cancer (SimCRC) to estimate the effectiveness of CRC screening and the lifetime costs (payers' perspective) for a cohort of US 50-years-old persons to whom CRC screening is offered from age 50-75. We compared annual screening with guaiac and immunochemical FOBTs (with sensitivities up to 70 and 24% for CRC and adenomas, respectively) to annual screening with a hypothetical NIT (sensitivity of 90% for CRC, no detection of adenomas beyond chance, specificity and cost similar to FOBTs). Screening with the NIT was not more effective, but was 29-44% more costly than screening with FOBTs. The findings were robust to varying the screening interval, the NIT's sensitivity for CRC, adherence rates favoring the NIT, and the NIT's unit cost. A comparative modelling approach using a model that assumes a shorter adenoma dwell time (MISCAN-COLON) confirmed the superiority of the immunochemical FOBT over an NIT with no ability to detect adenomas. Information on adenoma detection is crucial to determine whether a new NIT is a viable alternative to FOBTs for CRC screening. Current evidence thus lacks an important piece of information to identify marker candidates that hold real promise and deserve further (large-scale) evaluation.

Colon capsule endoscopy

Colon capsule endoscopy (CCE) is a minimally invasive technique specifically designed to explore the colon without sedation and air insufflation. CCE may overcome some of the limitations of colonoscopy. Second-generation CCE (CCE-2) was proved accurate in detecting colonic neoplastic lesions when used in average-risk individuals. The evidence to date supports the use of CCE-2 in cases of colonoscopy failure, in patients unwilling to undergo colonoscopy, and when colonoscopy is contraindicated. Other potential applications, such as colorectal cancer screening or diagnostic surveillance of inflammatory bowel disease, require clarification.

Factors associated with false-positive and false-negative fecal immunochemical test results for colorectal cancer screening

BACKGROUND

Certain subgroups have higher rates of false fecal immunochemical test (FIT) results, yet few studies have addressed this topic.

OBJECTIVE

To identify demographic factors associated with false-positive and false-negative FIT results in colorectal cancer screening.

DESIGN

Retrospective database review of prospectively collected data.

SETTING

A bowel cancer screening center in Hong Kong invited participants for colorectal cancer screening (2008-2012).

PATIENTS

Study participants who underwent both FIT and colonoscopy in the first year (n = 4482) and underwent colonoscopy after negative FIT results for 3 consecutive years (n = 857).

MAIN OUTCOME MEASUREMENTS

The diagnostic accuracy and predictive values of FIT according to participant characteristics.

RESULTS

The sensitivity, specificity, positive predictive values, and negative predictive values for advanced neoplasia were 33.1%, 91.9%, 19.0%, and 96.0%, respectively. Participants 66 to 70 years of age had higher sensitivity, whereas older age, smoking, and use of aspirin/nonsteroidal anti-inflammatory drugs were associated with lower specificity. The rates of false-positive and false-negative results were 8.1% and 66.9%, respectively. Older age (66-70 years; adjusted odds ratio [AOR] 1.95; 95% confidence interval [CI], 1.35-2.81; P < .001), smoking (AOR 1.68; 95% CI, 1.08-2.61; P = .020), and the presence of polypoid adenoma (AOR 1.71; 95% CI, 1.14-2.57; P = .009) were associated with false-positive results. Younger participants (AOR for elderly participants 0.31) and the use of aspirin/nonsteroidal anti-inflammatory drugs (AOR 4.44) in participants with 1 FIT with negative results and the absence of high-grade dysplasia (AOR for presence 0.41) were associated with false-negative results.

LIMITATIONS

Self-referred participants who received one type of qualitative FIT.

CONCLUSION

These findings could be used to target screening more toward those with a higher risk of false-negative results and those with a lower risk of false-positive results for earlier colonoscopy.

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

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 µg 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 = 0.051). At the cut-off stablished, differences in FIT sensitivity (31.1%, 40.6%; p = 0.2) or specificity (96.5%, 97.3%; p = 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 µg/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.

The performance of three-sample qualitative immunochemical fecal test to detect colorectal adenoma and cancer in gastrointestinal outpatients: an observational study

BACKGROUND

Repeated qualitative fecal immunochemical test (qlFIT) is a clinical strategy widely used to detect lower gastrointestinal lesions, but its diagnostic power has not been assessed in opportunistic screening for colorectal neoplasia.

OBJECTIVE

This study aimed to determine the performance of three-sample qlFIT in screening for colorectal cancer and its precursors in high-risk participants.

METHODS

513 gastrointestinal outpatients yielded three qlFITs before a standard colonoscopy. We evaluated the diagnostic value of one, two, and three positive qlFITs serving as the positivity threshold. The risk factors of colorectal neoplasia to yield positive qlFITs were also determined.

RESULTS

52 patients were diagnosed with colorectal cancer and 70 with advanced adenomatous polyp. For colorectal cancer, the sensitivity and specificity of one positive qlFIT were 90.4% and 53.8%, of two were 80.8% and 75.1%, and of three were 53.9% and 88.5%, respectively. For advanced adenomatous polyp, the sensitivity and specificity of one positive qlFIT were 81.4% and 54.2%, of two were 50.0% and 72.5%, and of three were 28.6% and 86.2%. Left-sided location (OR 2.50, 95%CI 1.26-4.95) and advanced histology of tumors (OR 3.08, 95%CI 1.58-6.01) were independently associated with positive qlFITs.

CONCLUSIONS

Three-sample qlFIT is a reasonably good method to detect colorectal neoplasia in high-risk population. Tumors in the left side or with advanced pathological features are more likely to produce positive qlFITs.

Sex is a stronger predictor of colorectal adenoma and advanced adenoma than fecal occult blood test

Due to high costs and limited availability of screening colonoscopy, some screening programs require a positive fecal occult blood test (FOBT) before screening colonoscopy is remunerated. As male sex is a strong predictor of adenoma and advanced adenoma, we evaluated whether a positive FOBT or male sex is a stronger risk factor for adenoma and advanced adenoma. FOBT and screening colonoscopy results from 18.665 consecutive patients participating in a "national health check program" between 2009 and 2011 were included in this cohort study. Age-corrected adenoma detection rates (ADR), advanced adenoma detection rates (AADR) and carcinoma detection rates were calculated for men and women according to FOBT result separately. ADR and AADR in FOBT-positive men (34.6 and 11.8 %) and FOBT-negative men (29.1 and 7.6 %) were higher than ADR and AADR in FOBT-positive women (20 and 6.9 %) and in FOBT-negative women (17.6 and 4.4 %), (p = 0.0003). Men with negative FOBT were at higher risk of having an adenoma and advanced adenoma than women with positive FOBT (p < 0.0001). Odds ratios of a positive FOBT for ADR and AADR were 1.3 (1.1-1.5) (p = 0.0047) and 1.6 (1.2-2.1) (p < 0.0001), respectively. Odds ratios of male sex to predict ADR and AADR were significantly higher with 1.9 (1.8-2.1) and 1.8 (1.6-2), respectively (p < 0.001). Male sex is a stronger predictor for colorectal adenoma and advanced adenoma than positive FOBT. These results should be taken into account analyzing FOBT-based screening programs.

Attendance and yield over three rounds of population-based fecal immunochemical test screening

OBJECTIVES

Fecal immunochemical test (FIT) screening for colorectal cancer (CRC) requires timely successive rounds for an optimal preventive effect. However, data on attendance and trend in yield over multiple rounds of FIT screening are limited. We therefore conducted a consecutive third round of FIT screening in a population-based CRC screening trial.

METHODS

Average-risk subjects aged 50-74 years were approached for three rounds of 1-sample FIT (OC-sensor) screening. Subjects with a hemoglobin level ≥50 ng/ml (≥10 μg Hb/g) feces were referred for colonoscopy. Subjects with a positive FIT in previous rounds were not re-invited for FIT screening.

RESULTS

In the first round, 7,501 subjects were invited. The participation rate was 62.6% in the first round, 63.2% in the second round, and 68.3% in the third round (P<0.001). In total, 73% (5,241/7,229) of all eligible subjects participated in at least one of three rounds. The positivity rate was significantly higher in the first (8.4%) round compared with the second (6.0%) and third (5.7%) screening rounds (P<0.001). The detection rate of advanced neoplasia (AN) declined from the first round to subsequent rounds (round 1: 3.3%; round 2: 1.9%; and round 3: 1.3%; P<0.001). The positive predictive value for AN was 40.7% in the first screening round, 33.2% in the second screening round, and 24.0% in the third screening round (P<0.001).

CONCLUSIONS

Repeated biennial FIT screening is acceptable with increased participation in successive screening rounds, and >70% of all eligible subjects participating at least once over three rounds. The decline in screen-detected AN over three screening rounds is compatible with a decreased prevalence of AN as a result of repeated FIT screening. These findings provide strong evidence for the effectiveness of FIT screening and stress the importance of ongoing research over multiple screening rounds.

A score to estimate the likelihood of detecting advanced colorectal neoplasia at colonoscopy

OBJECTIVE

This study aimed to develop and validate a model to estimate the likelihood of detecting advanced colorectal neoplasia in Caucasian patients.

DESIGN

We performed a cross-sectional analysis of database records for 40-year-old to 66-year-old patients who entered a national primary colonoscopy-based screening programme for colorectal cancer in 73 centres in Poland in the year 2007. We used multivariate logistic regression to investigate the associations between clinical variables and the presence of advanced neoplasia in a randomly selected test set, and confirmed the associations in a validation set. We used model coefficients to develop a risk score for detection of advanced colorectal neoplasia.

RESULTS

Advanced colorectal neoplasia was detected in 2544 of the 35,918 included participants (7.1%). In the test set, a logistic-regression model showed that independent risk factors for advanced colorectal neoplasia were: age, sex, family history of colorectal cancer, cigarette smoking (p<0.001 for these four factors), and Body Mass Index (p=0.033). In the validation set, the model was well calibrated (ratio of expected to observed risk of advanced neoplasia: 1.00 (95% CI 0.95 to 1.06)) and had moderate discriminatory power (c-statistic 0.62). We developed a score that estimated the likelihood of detecting advanced neoplasia in the validation set, from 1.32% for patients scoring 0, to 19.12% for patients scoring 7-8.

CONCLUSIONS

Developed and internally validated score consisting of simple clinical factors successfully estimates the likelihood of detecting advanced colorectal neoplasia in asymptomatic Caucasian patients. Once externally validated, it may be useful for counselling or designing primary prevention studies.

Application of fecal hemoglobin-haptoglobin complex testing for small bowel lesions

OBJECTIVE

Fecal hemoglobin-haptoglobin (Hb-Hpt) complex testing is theoretically superior to immunochemical fecal occult blood test detecting human hemoglobin (Hb), as Hb-Hpt is more stable compared to Hb during passage through the gastrointestinal (GI) tract. The aim was to examine the role of fecal Hb-Hpt complex testing in predicting small bowel lesions detected by video capsule endoscopy (VCE).

MATERIALS AND METHODS

Stools from patients undergoing small bowel VCE for obscure GI bleeding (OGIB) without ongoing overt bleeding were included. Two stool specimens were obtained on different days just before VCE to measure Hb-Hpt complex by ELISA and Hb by latex agglutination turbidimetric immunoassay.

RESULTS

Seventy-six patients (39 men and 37 women, average age 66 years) with suspected small bowel lesions entered. Median Hb-Hpt complex and Hb levels were significantly higher (p<0.001) in those with small bowel lesions compared to those without. Using the suitable cutoff points (Hb>0 ng/ml and Hb-Hpt complex>5 ng/ml), the sensitivity and specificity of the Hb-Hpt complex test to predict small bowel lesions were 71.4% and 73.3%, and those of the Hb test were 61.2% and 89.3%. Small bowel lesions were found in 58.3% with only Hb-Hpt complex positive results (15.8% of total subjects) compared to 83.3% when both were positive (55.3% of total).

CONCLUSIONS

Measuring fecal Hb-Hpt complex in addition to Hb may be useful to predict the presence of small bowel lesions in patients with OGIB.

Development and validation of a scoring system to identify individuals at high risk for advanced colorectal neoplasms who should undergo colonoscopy screening

BACKGROUND & AIMS

Screening the population for colorectal cancer (CRC) by colonoscopy could reduce the disease burden. However, targeted screening of individuals at high risk could increase its cost effectiveness.

METHODS

We developed a scoring system to identify individuals with at least 1 advanced adenoma, based on easy-to-collect risk factors among 7891 participants of the German screening colonoscopy program. The system was validated in an independent sample of 3519 participants. Multiple logistic regression was used to develop the algorithm, and the regression coefficient-based scores were used to determine individual risks. Relative risk and numbers of colonoscopies needed for detecting one or more advanced neoplasm(s) were calculated for quintiles of the risk score. The predictive ability of the scoring system was quantified by the area under the curve.

RESULTS

We identified 9 risk factors (sex, age, first-degree relatives with a history of CRC, cigarette smoking, alcohol consumption, red meat consumption, ever regular use [at least 2 times/wk for at least 1 y] of nonsteroidal anti-inflammatory drugs, previous colonoscopy, and previous detection of polyps) that were associated significantly with risk of advanced neoplasms. The developed score was associated strongly with the presence of advanced neoplasms. In the validation sample, individuals in the highest quintile of scores had a relative risk for advanced neoplasm of 3.86 (95% confidence interval, 2.71-5.49), compared with individuals in the lowest quintile. The number needed to screen to detect 1 or more advanced neoplasm(s) varied from 20 to 5 between quintiles of the risk score. In the validation sample, the scoring system identified patients with CRC or any advanced neoplasm with area under the curve values of 0.68 and 0.66, respectively.

CONCLUSIONS

We developed a scoring system, based on easy-to-collect risk factors, to identify individuals most likely to have advanced neoplasms. This system might be used to stratify individuals for CRC screening.

Fecal immunochemical test accuracy in average-risk colorectal cancer screening

AIM: To assess the fecal immunochemical test (FIT) accuracy for colorectal cancer (CRC) and advanced neoplasia (AN) detection in CRC screening.

METHODS: We performed a multicentric, prospective, double blind study of diagnostic tests on asymptomatic average-risk individuals submitted to screening colonoscopy. Two stool samples were collected and the fecal hemoglobin concentration was determined in the first sample (FIT1) and the highest level of both samples (FITmax) using the OC-sensor™. Areas under the curve (AUC) for CRC and AN were calculated. The best FIT1 and FITmax cut-off values for CRC were determined. At this threshold, number needed to scope (NNS) to detect a CRC and an AN and the cost per lesion detected were calculated.

RESULTS: About 779 individuals were included. An AN was found in 97 (12.5%) individuals: a CRC in 5 (0.6%) and an advanced adenoma (≥ 10 mm, villous histology or high grade dysplasia) in 92 (11.9%) subjects. For CRC diagnosis, FIT1 AUC was 0.96 (95%CI: 0.95-0.98) and FITmax AUC was 0.95 (95%CI: 0.93-0.97). For AN, FIT1 and FITmax AUC were similar (0.72, 95%CI: 0.66-0.78 vs 0.73, 95%CI: 0.68-0.79, respectively, P = 0.34). Depending on the number of determinations and the positivity threshold cut-off used sensitivity for AN detection ranged between 28% and 42% and specificity between 91% and 97%. At the best cut-off point for CRC detection (115 ng/mL), the NNS to detect a CRC were 10.2 and 15.8; and the cost per CRC was 1814€ and 2985€ on FIT1 and FITmax strategies respectively. At this threshold the sensitivity, NNS and cost per AN detected were 30%, 1.76, and 306€, in FIT1 strategy, and 36%, 2.26€ and 426€, in FITmax strategy, respectively.

CONCLUSION: Performing two tests does not improve diagnostic accuracy, but increases cost and NNS to detect a lesion.

A plasma microRNA panel for detection of colorectal adenomas: a step toward more precise screening for colorectal cancer

OBJECTIVE

The main objective of this study was to investigate the potential use of circulating microRNAs (miRNAs) as biomarkers of colorectal (CR) adenomas.

BACKGROUND

Detection of precancerous lesions such as CR adenoma is a key to reduce CR cancer (CRC) mortality. There is a great need for accurate, noninvasive biomarkers for detection of CR adenoma and CRC. MiRNAs are non-protein-coding RNAs that regulate gene expression. Our prior work investigated the dysregulation of 5 plasma miRNAs in CRC patients. As intended, we undertook a more comprehensive plasma-miRNA screening study in patients with CR adenoma and CRC.

METHODS

We screened for 380 plasma-miRNAs using microfluidic array technology (Applied BioSystems) in a screening cohort of 12 healthy controls, 9 patients with CR adenomas, and 20 patients with CRC. A panel of the most dysregulated miRNAs (P < 0.05, False Discovery Rate: 5%) was then validated in a blinded cohort of 26 healthy controls, 16 patients with large adenomas, and 45 patients with CRC.

RESULTS

A panel of 8 plasma miRNAs (miR-532-3p, miR-331, miR-195, miR-17, miR-142-3p, miR-15b, miR-532, and miR-652) distinguished polyps from controls with high accuracy [area under curve (AUC) = 0.868 (95% confidence interval [CI]: 0.76-0.98)]. In addition, a panel of 3 plasma miRNAs (miR-431, miR-15b, and miR-139-3p) distinguished Stage IV CRC from controls with an [AUC = 0.896 (95% CI: 0.78-1.0)]. Receiver-operating-characteristic curves of miRNA panels for all CRC versus controls and polyps versus all CRC showed AUC values of 0.829 (95% CI: 0.73-0.93) and 0.856 (95% CI: 0.75-0.97), respectively.

CONCLUSIONS

Plasma miRNAs are reliable, noninvasive, and inexpensive markers for CR adenomas. This miRNA panel warrants study in larger cohorts. Plasma-based assays could provide better screening compliance compared to fecal occult blood or endoscopic screening.

Well adjusted qualitative immunochemical faecal occult blood tests could be a promising alternative for inexpensive, high-quality colorectal cancer screening

Immunochemical faecal occult blood tests (iFOBTs) have been shown to have higher sensitivity to detect colorectal cancer (CRC) and its precursors than traditional guaiac-based faecal occult blood tests, but are more costly and require specific laboratory equipment. A number of qualitative iFOBTs have been developed, but their performance varied widely because of the large variation in positivity thresholds used for test positivity. We aimed to evaluate the performance of qualitative iFOBTs with well adjusted positivity thresholds in the screening setting. In a study of 229 participants who underwent screening colonoscopy in Germany (45 patients with CRC, 65 with advanced adenoma and 119 free of colorectal neoplasms), we evaluated the performance of two qualitative iFOBTs at five different positivity thresholds and compared it with the performance of a quantitative iFOBT. Receiver operating characteristic curves were constructed. The areas under the curve, and the sensitivity and specificity of the tests, were calculated. For both qualitative tests, sensitivities were around 30% for advanced adenoma and 80% for CRC at very high levels of specificity (98-99%). Comparison of results with the receiver operating characteristic curves for the quantitative test indicated that the qualitative tests yielded similarly high levels of sensitivity at comparable levels of specificity. In conclusion, with appropriate adjustment of positivity thresholds ensuring the levels of specificity required in population-based screening, qualitative, office-based iFOBTs can be an economic, qualitatively comparable alternative to quantitative iFOBTs.

Comparative evaluation of nine faecal immunochemical tests for the detection of colorectal cancer

BACKGROUND

Faecal immunochemical tests (FITs) for haemoglobin are increasingly used for non-invasive screening for colorectal cancer (CRC) but large scale comparative studies of different FITs for detection of CRC, overall and by stage, are sparse. We aimed to determine and compare performance of different FITs for the detection of CRC, and to assess their stage-specific sensitivities.

MATERIAL AND METHODS

We assessed sensitivity, specificity and their corresponding 95% confidence intervals for six qualitative FITs among 74 CRC cases (59% stage I or II cancers) and 1480 controls free of colorectal neoplasm. Overall and stage-specific receiver operating characteristic curves were derived for three quantitative FITs. The areas under the curves (AUCs) were calculated and compared.

RESULTS

Pairs of overall sensitivity and specificity of the qualitative FITs ranged from 66% and 96% to 92% and 62%, respectively. For the three quantitative tests, AUCs ranged from 0.90 to 0.92, with sensitivities ranging from 80% to 87% at cut-offs yielding 90% specificity. AUCs ranged from 0.85 to 0.92, 0.94 to 0.96, and 0.86 to 0.93 for stage I, stage II and advanced stages (stage III and IV) cancers, respectively. At a specificity of 90%, the tests detected 65%-85% of stage I cancers.

CONCLUSION

The diagnostic performance of FITs regarding detection of CRC is promising, even though the pre-defined cut-offs of some of the qualitative FITs need to be adjusted to limit false-positive rates in screening setting. At cut-off levels yielding 90% specificity, the quantitative tests detected the vast majority of CRCs, even at early stages.

Use of a low cut-off value for the fecal immunochemical test enables better detection of proximal neoplasia

BACKGROUND

The advantage of the quantitative fecal immunochemical test (FIT) is the flexibility to set the positivity threshold. However, the diagnostic success of the FIT has not been compared for standard and low cut-off thresholds.

AIMS

The purpose of this study was to compare the diagnostic success of FIT for standard and low cut-off thresholds.

METHODS

In 2009 and 2010 a standard cut-off threshold (20 μg Hb/g feces) was used as positivity criterion for the FIT; in 2012 a low cut-off (10 μg Hb/g feces) was used. Diagnostic success was compared between the two groups.

RESULTS

Of the total of 14,289 participants, 195 (1.4 %) had positive FIT results. Positivity of the FIT was significantly higher in the low cut-off group than in the standard cut-off group (1.8 vs. 1.0 %, p = 0.000). Although detection of advanced neoplasia lesions was comparable, proximal neoplasia was more frequently detected in the low cut-off group (33.3 vs. 20.9 %, p = 0.016). With the low cut-off threshold, 39 (0.7 %) participants were also classified as having positive results, and 18 (46.2 %) of these had colorectal neoplasias. The number of positive results from the FIT was increased by 54.9 %, and detection of advanced neoplasia was increased by 60 % with the low cut-off threshold compared with the standard cut-off.

CONCLUSIONS

A low cut-off threshold for the FIT resulted in better detection of proximal neoplasia in population-based screening. These results indicate the cut-off threshold for positive FIT should be properly chosen and adjusted in colorectal cancer screening.

Diagnostic accuracy of faecal immunochemical test for screening individuals with a family history of colorectal cancer

BACKGROUND

The role of a faecal immunochemical test (FIT) in screening individuals with a positive family history of colorectal cancer (CRC) is not clear.

AIM

To assess the diagnostic accuracy of FIT using colonoscopy findings as the gold standard in identifying colorectal neoplasms.

METHODS

We analysed data from 4539 asymptomatic subjects aged 50-70 years who had both colonoscopy and FIT (Hemosure; W.H.P.M., Inc, El Monte, CA, USA) at our bowel cancer screening centre between 2008 and 2012. A total of 572 subjects (12.6%) had a family history of CRC. Our primary outcome was the sensitivity of FIT in detecting advanced neoplasms and cancers in subjects with a family history of CRC. A family history of CRC was defined as any first-degree relative with a history of CRC.

RESULTS

Among 572 subjects with a family history of CRC, adenoma, advanced neoplasm and cancer were found at screening colonoscopy in 29.4%, 6.5% and 0.7% individuals, respectively. The sensitivity of FIT in detecting adenoma, advanced neoplasm and cancer was 9.5% [95% confidence interval (CI), 5.7-15.3], 35.1% (95% CI, 20.7-52.6) and 25.0% (95% CI, 1.3-78.1), respectively. Among FIT-negative subjects who have a family history of CRC, adenoma was found in 152 (29.6%), advanced neoplasm in 24 (4.7%) and cancer in 3 (0.6%) individuals.

CONCLUSION

Compared with colonoscopy, FIT is more likely to miss advanced neoplasms or cancers in individuals with a family history of CRC.

Fecal immunochemical test accuracy in familial risk colorectal cancer screening

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 1,064€ and 1591.33€ 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.