Jeffrey K. Lee

Accuracy of Fecal Immunochemical Tests for Colorectal Cancer: Systematic Review and Meta-analysis

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths in the United States (1). Randomized, controlled trials have shown that annual or biennial fecal occult blood tests (FOBTs) are associated with a 15% to 33% decrease in CRC mortality rates (24). However, FOBTs only detect approximately 13% to 50% of cancer with 1 round of screening in asymptomatic patients (5, 6). In addition, adherence to repeated rounds of FOBTs in real-world screening programs is low, raising concern about their effectiveness as screening tests (7, 8). Fecal immunochemical tests (FITs) are more sensitive at detecting both CRC and adenomas than FOBTs (9, 10). Many FITs require only 1 or 2 stool samples, and none require dietary or medication restrictions, increasing ease of use. In 2008, several U.S. professional societies endorsed the use of FITs to replace FOBTs because of the formers improved performance characteristics and potential for higher participation rates (10, 11). Countries in Europe and Asia have also adopted widespread CRC screening programs using FITs (12, 13). However, the diagnostic characteristics of these tests have been difficult to estimate, with reported sensitivities ranging from 25% to 100% for CRC and specificities usually exceeding 90% (9, 14, 15). The lack of a precise estimate of sensitivity has resulted in confusion among health care providers about the sources of this variation, how best to apply FITs for CRC screening, the optimal number of stool samples for testing, optimal cutoff value for a positive test result, and whether any brand of FIT is superior to others. Our analysis provides a quantitative meta-analysis of the diagnostic accuracy (sensitivity and specificity) of FITs for CRC. In addition, we explored potential sources of heterogeneity by analyzing subgroups classified by FIT sample number, cutoff value for a positive test result, FIT brand, and the reference standard. Methods We developed a protocol on the basis of standard guidelines for the systematic review of diagnostic studies (16, 17) and the strategy used for the U.S. Preventive Services Task Force review in 2008 (9). We followed the STARD (Standards for the Reporting of Diagnostic Accuracy Studies) (18) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) (19) statements for reporting our systematic review. This study was conducted as part of the National Cancer Institutefunded consortium, Population-Based Research Optimizing Screening through Personalized Regimens. The overall aim of this consortium is to conduct multisite, coordinated, transdisciplinary research to evaluate and improve cancer screening processes. Data Sources and Searches We included all studies identified in the previous USPSTF report (9) plus other studies identified by a search of FIT for CRC between 1 January 2008 and 31 August 2013 using MEDLINE (via Ovid), EMBASE, Database of Abstracts of Reviews of Effects, Health Technology Assessment Database, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials. We also searched bibliographies and reference lists of eligible papers and related reviews, consulted experts in the field, and contacted several authors from the included studies to locate additional studies. The Appendix Table 1 provides further details of our search strategy. Appendix Table 1. Search Strategy Study Selection Two persons independently reviewed the pertinent studies to determine eligibility. We included studies if they met all of the following criteria: evaluated the diagnostic accuracy of FITs for CRC; reported absolute numbers of true-positive, false-negative, true-negative, and false-positive observations, or if these same variables could be obtained from personal communication; used a randomized trial or cohort study design; evaluated adult participants who were asymptomatic and older than 18 years with a mean age greater than 40 years; and reported an appropriate reference standard (colonoscopy or 2-year longitudinal follow-up of controls with medical records or cancer registry). Given that only a subset of studies reported data on adenomatous polyps and that there is variability in definitions of polyps, we limited the scope of this analysis to test performance characteristics for detecting CRC; we excluded studies reporting test performance estimates for detection of adenomas only. We did not include conference abstracts and casecontrol studies, which, by creating spectrum bias, can overestimate the accuracy of a test (20). To avoid duplicate reporting of the same population for studies reporting several cutoff values or numbers of samples, we used the cutoff value or sample number most commonly used in current practice in the United States, used in national recommendations, or recommended by expert opinion in the main analyses. In addition, we selected the sample number or cutoff value a priori that was most similar to those in other studies for our subgroup analyses. Data Extraction and Quality Assessment Two reviewers independently evaluated and extracted relevant information from each included study and assessed study quality via the Quality Assessment of Diagnostic Accuracy Studies 2 instrument (21). For studies with incomplete or unavailable information, we contacted the corresponding authors or coauthors to complete missing information. Of the 15 contacted authors, 12 provided additional data. We converted units for cutoff thresholds for a positive test result in each study to micrograms of hemoglobin per gram of stool, as recommended by leading experts (22). Data Synthesis and Analysis We calculated the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio (LR), and negative LR with 95% CI of each study. A positive LR greater than 5 and a negative LR less than 0.2 provide strong diagnostic evidence to rule in or rule out diagnoses, respectively (23). The overall pooled sensitivity and specificity of FIT for CRC were estimated using a bivariate random-effects model (24). We calculated the pooled positive LR and negative LR along with the respective CI using the bivariate model (24) according to the method used by Zwinderman and colleagues (25). We also generated a hierarchical summary receiver-operating characteristic curve that plots the individual and summary estimates of sensitivities and specificities along with a 95% confidence and prediction region (26). Last, we calculated the area under the hierarchical summary receiver-operating characteristic curve. An area under the curve between 0.9 and 1.0 indicates that the test in question is highly accurate (27). The Q value and the inconsistency index (I 2) test were used to estimate the heterogeneity between each study (28). We regarded values of 25%, 50%, and 75% for the I 2 as indicative of low, moderate, and high statistical heterogeneity, respectively (28). In addition, we calculated the between-study variance of logit sensitivity and logit specificity (24, 29). In diagnostic accuracy studies, 1 of the primary causes of heterogeneity is the threshold effect, which occurs when different cutoff values are used between studies to define a positive (or negative) test result. We searched for evidence of a threshold effect by calculating the squared correlation coefficient estimated from the between-study covariance variable in the bivariate model (30). We stratified studies into 4 subgroups on the basis of the number of FIT samples (1, 2, or 3 samples), prespecified cutoff values of fecal hemoglobin concentration for a positive test result (<20 g/g, 20 to 50 g/g, and >50 g/g), brand, and reference standard used to follow up on patients with negative FIT results. Cutoff values were grouped to ensure an adequate number of data sets for each analysis. To determine whether studies using older (discontinued) FITs were causing heterogeneity in our summary estimates, we did sensitivity analyses by removing these studies and recalculating the I 2 test for the remaining group. In addition to threshold effect and subgroup analyses, we did a bivariate random-effects meta-regression analysis to identify additional sources of heterogeneity that may have influenced our overall summary estimates (30). We used the following prespecified variables for our meta-regression: type of FIT (qualitative, point-of-care tests or quantitative, automated tests), geographic region (Asian or non-Asian countries), and enrollment of patients younger than 40 years. We used Stata, version 12.0 (StataCorp, College Station, Texas), for all statistical analyses. All tests were 2-sided, and we considered P values less than 0.05 to be statistically significant. Role of the Funding Source The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Cancer Institute. The funding source had no role in the conception, design, analysis, or conduct of the review. Results Study Selection The 2008 USPSTF report (9) included 9 studies in its systematic review (3139); our literature search identified 1771 additional new potential sources (Figure 1). After abstract review, we identified 53 articles for full-text review; of these, 18 unique articles satisfied all inclusion criteria and were included in our analysis (14, 15, 3146). Because 1 article (46) evaluated more than 1 FIT brand in a head-to-head comparison, the final analysis included 19 studies or data sets. Figure 1. Summary of evidence search and selection. USPSTF = U.S. Preventive Services Task Force. Characteristics of Included Studies Table 1 and the Supplement show the main characteristics of the included studies. Eighteen articles described 19 cohort studies of FIT sensitivity and specificity for CRC in average-risk asymptomatic patients; sample sizes ranged from 80 to 27860. Twelve studies (14, 3336, 4042, 4446) used colonoscopy in all patients, regardless of FIT results, as the re

Endoscopy Is Accurate, Safe, and Effective in the Assessment and Management of Complications Following Gastric Bypass Surgery

OBJECTIVES:Roux-en-Y gastric bypass (RYGB) is a common intervention for morbid obesity. Upper gastrointestinal (UGI) symptoms are frequent and difficult to interpret following RYGB. The aim of our study was to examine the role of endoscopy in evaluating UGI symptoms after RYGB and to assess the safety and efficacy of endoscopic therapy.METHODS:Between 1998 and 2005, a total of 1,079 patients underwent RYGB for clinically severe obesity and were followed prospectively. Patients with UGI symptoms after RYGB who were referred for endoscopy were studied.RESULTS:Of 1,079 patients, 76 (7%) who underwent RYGB were referred for endoscopy to evaluate UGI symptoms. Endoscopic findings included normal surgical anatomy (n=24, 31.6%), anastomotic stricture (n=40, 52.6%), marginal ulcer (n=12, 15.8%), unraveled nonabsorbable sutures causing functional obstruction (n=3, 4%) and gastrogastric fistula (n=2, 2.6%). Patients with abnormal findings on endoscopy presented with UGI symptoms at a mean of 110.7 days from their RYGB, which was significantly shorter than the time of 347.5 days for patients with normal endoscopy (P<0.001). A total of 40 patients with anastomotic strictures underwent 86 endoscopic balloon dilations before complete symptomatic relief. In one patient, a needle knife was used to open a completely obstructed anastomotic stricture. Unraveled, nonabsorbable suture material was successfully removed using endoscopic scissors in three patients.CONCLUSIONS:Patients presenting with UGI symptoms less than 3 months after surgery are more likely to have an abnormal finding on endoscopy. Endoscopic balloon dilation is safe and effective in managing anastomotic strictures. Endoscopic scissors are safe and effective in removing unraveled, nonabsorbable sutures contributing to obstruction.

EUS diagnosis of vascular invasion in pancreatic cancer: Surgical and histologic correlates

BACKGROUND:Endoscopic ultrasound (EUS) has been compared to intraoperative surgical palpation for diagnosis of vascular invasion by pancreatic cancer. This study compares EUS with vascular resection and histologic evidence of vascular invasion in resected pancreatic masses.METHODS:All patients with solid pancreatic masses who underwent both preoperative EUS and surgery at 1 hospital over a 7 year period were identified. The relationship of pancreatic masses to adjacent vessels was prospectively assessed by EUS. EUS findings were compared to surgical and pathology gold standards. “Vascular adherence” was defined as tumor adherence requiring vascular resection during surgery, and “vascular invasion” as histologic invasion of vessel wall by tumor.RESULTS:30 of 68 patients were resectable. Among these 30, vascular adherence was present in 8, including 18% of patients with an intact echoplane between tumor and adjacent vessels at EUS, 29% of those with loss of echoplane alone, and 50% of those with additional EUS features of vascular involvement. Vascular invasion was present in 4, including 12% of patients with an intact echoplane, 0% of those with loss of echoplane alone, and 33% of those with additional EUS features. Sensitivity, specificity, PPV, and NPV of EUS were 63%, 64%, 43% and 80% for vascular adherence and 50% 58%, 28% and 82% for vascular invasion. NPV rose to 90% for vascular adherence if only the portal confluence vessels were considered.CONCLUSIONS:EUS has poor sensitivity, specificity, and positive predictive value for diagnosis of venous involvement by pancreatic cancer.

Fecal Immunochemical Test Program Performance Over 4 Rounds of Annual Screening: A Retrospective Cohort Study

Context The fecal immunochemical test is an effective way to screen for colorectal cancer, but we know more about how well it does the first time it is used and less about how well it does in later years with repeated testing. Contribution The researchers show that, after 4 years of repeated testing, patients continued to use the test and it continued to identify colorectal cancer. Caution This study did not measure whether identification of cancer changed outcomes. Implication The fecal immunochemical test is acceptable and effective for repeated testing. Colorectal cancer (CRC) is the second leading cause of cancer death in the United States (13), and screening with fecal occult blood tests (FOBTs) reduces CRC incidence and mortality (46). In randomized trials (711), annual or biennial guaiac-based FOBTs reduced CRC incidence by 17% to 20% and CRC mortality by 15% to 33%. Thus, the U.S. Preventive Services Task Force (4) and U.S. Multi-Society Task Force on Colorectal Cancer (12) recommend annual FOBT as an option for CRC screening for average-risk patients, defined as those aged 50 to 75 years with no history of CRC or adenoma, with no first-degree relatives with CRC, and who are not up to date with CRC screening according to other methods (that is, sigmoidoscopy within 5 years or colonoscopy within 10 years). Annual highly sensitive FOBTs are believed to be as effective as screening colonoscopy performed every 10 years if levels of adherence are high (13), although colonoscopy is recommended for those with a family history of CRC. Fecal blood tests are noninvasive and can be delivered by mail (14). In contrast to guaiac-based stool tests, fecal immunochemical test (FIT) screening can be done without dietary or medication restrictions, which allows it to achieve higher patient acceptance in organized CRC screening programs (15). This test also has higher detection rates for CRC and advanced adenomas than guaiac-based stool tests (1517). In a recent meta-analysis (18), the sensitivity of a single FIT application was 79% for CRC diagnosed within 2 years of testing; however, little is known about performance characteristics over several rounds of annual screening, particularly in community practice. The present study was conducted to evaluate FIT sensitivity for CRC and other performance characteristics over 4 rounds of annual testing in a U.S. community-based CRC screening program. Methods Study Population This retrospective longitudinal study was performed in a fixed cohort of Kaiser Permanente Northern California (KPNC) and Southern California (KPSC) health plan members. These integrated health care delivery organizations serve approximately 7 million persons in urban, suburban, and semirural regions throughout California. Kaiser Permanente health plan membership in California is diverse and similar in socioeconomic characteristics to the regions census demographics (1921). Study Oversight The study was approved by the institutional review boards of KPNC and KPSC, both of which waived the requirement for informed consent. The listed authors had sole responsibility for the study design, data collection, decision to submit the manuscript for publication, and drafting of the manuscript. This study was conducted within the National Cancer Institutefunded Population-based Research Optimizing Screening through Personalized Regimens (PROSPR) consortium, which conducts multisite, coordinated, transdisciplinary research to evaluate and improve cancer-screening processes. Organized CRC Screening Program The KPNC and KPSC initiated similar organized FIT screening programs between 2006 and 2008; the KPNC program has been described previously (14). Briefly, each year, the programs mail a FIT kit to eligible health plan members aged 50 to 75 years without a record of a colonoscopy within 10 years, sigmoidoscopy within 5 years, or fecal blood test within the prior year. The kit includes the FIT (OC FIT-CHEK; Polymedco), a standardized letter from the patients primary care provider, directions for completing and mailing the test, and a preprinted laboratory requisition order form. Outreach includes in-person, mail, secure e-mail, and telephone reminders as needed. The kits are returned by mail to regional laboratories and analyzed on or shortly after the return date using an OC-Sensor Diana automated system (Polymedco) with a cutoff level of 20 g of hemoglobin/g of buffer for a positive result. Patients with a positive FIT result are referred for follow-up colonoscopy. Study Eligibility Criteria and Participant Tracking The study cohort included CRC screening program participants aged 50 to 70 years on the date an initial kit was mailed to them in 2007 or 2008. Patients were excluded if they had been enrolled in the health plan for less than 1 year before the round 1 FIT mail date (to allow for the recording of prior out-of-system endoscopy procedures). They were also excluded if they were mailed a kit but subsequently had sigmoidoscopy or colonoscopy, were diagnosed with CRC, died, or terminated membership in the health plan before returning the initial FIT or within 1 year after their round 1 mail date if no FIT was returned. A total of 670841 health plan members was mailed the initial kit in 2007 or 2008 and met the study eligibility criteria; 323349 (48.2%) returned a FIT within 1 year after the mail date (Figure). The analytic cohort comprised these round 1 participants who were tracked from their baseline mail date (cohort entry) through up to 4 rounds of testing for mail dates; result dates; results (positive or negative); whether follow-up colonoscopy was performed within 1 year after a positive FIT result; and diagnoses of adenoma, adenoma with advanced histology, and CRC. Cohort members were followed for CRC through the follow-up screening rounds, even if they subsequently became ineligible for screening because of sigmoidoscopy or colonoscopy. Patients were censored at the time of CRC diagnosis, death, or termination of membership in the health plan if they did not rejoin. Figure. Study flow diagram.* The figure includes 1192 patients with CRC who were screened by FIT the year before diagnosis. Further, there were 118 additional patients with CRC diagnosed more than 1 y beyond the FIT screening date and 101 additional patients diagnosed with CRC who either crossed over to endoscopy in subsequent rounds or terminated health plan membership but then rejoined. CRC = colorectal cancer; FIT = fecal immunochemical test. * Shading indicates where patients were censored or became ineligible for subsequent FIT screening. Patients were eligible for the initial FIT mailing if they were aged 50 to 70 y and had 1 y of membership. See Methods section for exclusions. Number censored because of CRC and includes patients with CRC diagnosed within 1 y after their FIT result. Defining Annual Screening Episodes For each patient, the initial kit mail date in 2007 or 2008 was the anchor date for round 1 and for each subsequent round of testing. However, because subsequent mailing dates varied each round, mail dates within 3 months before to 12 months after each subsequent rounds anchor date were counted as having been distributed during that specific round. For example, a patient with a round 1 mail date of 15 March 2007 had subsequent anchor dates of 15 March for rounds 2 through 4 (2008, 2009, and 2010, respectively). If their next FIT was mailed on 15 January 2008, the test was considered to be distributed in round 2 because the second mail date occurred within 3 months of the round 2 anchor date. The FIT results recorded within 1 year of each mail date, and colonoscopies performed and adenomas or CRC diagnosed within 1 year after FIT results, were considered part of a single screening episode for the round when the FIT was distributed. Among round 1 participants, FITs with no recorded mail dates returned in rounds 2 through 4 were assumed to be distributed through in-reach methods (such as a clinic visit) and were counted in the follow-up round returned. In general, the first result per patient was counted in any given round. The earliest possible date of cohort entry (first mail date) was 1 January 2007, and the last possible date of follow-up was 31 December 2013 (12 months after the last possible FIT result date of 31 December 2012). Data Sources The FIT-related dates and results were obtained from the CRC screening program and laboratory databases for each region, respectively. Endoscopy procedures were identified using Current Procedural Terminology codes (22). Adenoma diagnoses used Systematized Nomenclature of Medicine codes. Prior validation studies have confirmed high levels of sensitivity and accuracy for capture of colonoscopy examinations and assignment of adenoma status (23). Colorectal adenocarcinomas and disease stage were obtained from the KPNC and KPSC cancer registries, which report to the SEER (Surveillance, Epidemiology, and End Results) registry. Cancer databases capture more than 98% of cancer diagnoses within the KPNC and KPSC populations. Advanced-stage cancer was defined as stage III (regional disease with spread to regional lymph nodes only) or stage IV (distant metastasis) according to the American Joint Committee on Cancer staging system; for patients who did not have such staging, advanced-stage cancer was defined as code 3 (disease in the regional lymph nodes), code 4 (regional disease with direct extension and spread to regional lymph nodes), or code 7 (distant metastasis) according to the SEER Program Coding and Staging Manual 2013 (24). Data Analysis The following performance characteristics were calculated for each round of screening and overall: 1) participation (percentage of eligible patients who were distributed and completed a FIT within 1 year of their mailing date), 2) FIT positivity (percentage of participants who completed FITs and had positive results), 3) follow-up colonoscopy (per

BROAD-LINE REVERBERATION IN THE KEPLER-FIELD SEYFERT GALAXY Zw 229-015

The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from Hβ reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad Hβ flux. From cross-correlation measurements, we find that the Hβ light curve has a rest-frame lag of 3.86+0.69 –0.90 days with respect to the V-band continuum variations. We also measure reverberation lags for Hα and Hγ and find an upper limit to the Hδ lag. Combining the Hβ lag measurement with a broad Hβ width of σline = 1590 ± 47 km s–1 measured from the rms variability spectrum, we obtain a virial estimate of M BH = 1.00+0.19 –0.24 × 107 M ☉ for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

The Lick AGN Monitoring Project 2011: Reverberation Mapping of Markarian 50

The Lick AGN Monitoring Project 2011 observing campaign was carried out over the course of 11 weeks in spring 2011. Here we present the first results from this program, a measurement of the broad-line reverberation lag in the Seyfert 1 galaxy Mrk 50. Combining our data with supplemental observations obtained prior to the start of the main observing campaign, our data set covers a total duration of 4.5 months. During this time, Mrk 50 was highly variable, exhibiting a maximum variability amplitude of a factor of ~4 in the U-band continuum and a factor of ~2 in the Hβ line. Using standard cross-correlation techniques, we find that Hβ and Hγ lag the V-band continuum by τ_(cen) = 10.64^(+0.82)_(–0.93) and 8.43^(+1.30)_(–1.28) days, respectively, while the lag of He II λ4686 is unresolved. The Hβ line exhibits a symmetric velocity-resolved reverberation signature with shorter lags in the high-velocity wings than in the line core, consistent with an origin in a broad-line region (BLR) dominated by orbital motion rather than infall or outflow. Assuming a virial normalization factor of f = 5.25, the virial estimate of the black hole mass is (3.2 ± 0.5) × 10^7 M_☉. These observations demonstrate that Mrk 50 is among the most promising nearby active galaxies for detailed investigations of BLR structure and dynamics.

Association between serum interleukin-6 concentrations and mortality in older adults: the Rancho Bernardo study.

Background Interleukin-6 (IL-6) may have a protective role in acute liver disease but a detrimental effect in chronic liver disease. It is unknown whether IL-6 is associated with risk of liver-related mortality in humans. Aims To determine if IL-6 is associated with an increased risk of all-cause, cardiovascular disease (CVD), cancer, and liver-related mortality. Methods A prospective cohort study included 1843 participants who attended a research visit in 1984–87. Multiple covariates were ascertained including serum IL-6. Multivariable-adjusted Cox proportional hazards regression analyses were used to examine the association between serum IL-6 as a continuous (log transformed) variable with all-cause, CVD, cancer, and liver-related mortality. Patients with prevalent CVD, cancer and liver disease were excluded for cause-specific mortality. Results The mean (± standard deviation) age and body-mass-index (BMI) of participants was 68 (±10.6) years and 25 (±3.7) Kg/m2, respectively. During the 25,802 person-years of follow-up, the cumulative all-cause, CVD, cancer, and liver-related mortality were 53.1% (N = 978), 25.5%, 11.3%, and 1.3%, respectively. The median (±IQR) length of follow-up was 15.3±10.6 years. In multivariable analyses, adjusted for age, sex, alcohol, BMI, diabetes, hypertension, total cholesterol, HDL, and smoking, one-SD increment in log-transformed serum IL-6 was associated with increased risk of all-cause, CVD, cancer, and liver-related mortality, with hazard ratios of 1.48 (95% CI, 1.33–1.64), 1.38 (95% CI, 1.16–1.65), 1.35 (95% CI, 1.02–1.79), and 1.88 (95% CI, 0.97–3.67), respectively. CRP adjustment attenuated the effects but the association between IL-6 and all-cause and CVD mortality remained statistically significant, independent of CRP levels. Conclusions In community-dwelling older adults, serum IL-6 is associated with all-cause, CVD, cancer, and liver-related mortality.

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.

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.

Activin Signaling in Microsatellite Stable Colon Cancers Is Disrupted by a Combination of Genetic and Epigenetic Mechanisms

Background Activin receptor 2 (ACVR2) is commonly mutated in microsatellite unstable (MSI) colon cancers, leading to protein loss, signaling disruption, and larger tumors. Here, we examined activin signaling disruption in microsatellite stable (MSS) colon cancers. Methods Fifty-one population-based MSS colon cancers were assessed for ACVR1, ACVR2 and pSMAD2 protein. Consensus mutation-prone portions of ACVR2 were sequenced in primary cancers and all exons in colon cancer cell lines. Loss of heterozygosity (LOH) was evaluated for ACVR2 and ACVR1, and ACVR2 promoter methylation by methylation-specific PCR and bisulfite sequencing and chromosomal instability (CIN) phenotype via fluorescent LOH analysis of 3 duplicate markers. ACVR2 promoter methylation and ACVR2 expression were assessed in colon cancer cell lines via qPCR and IP-Western blots. Re-expression of ACVR2 after demethylation with 5-aza-2′-deoxycytidine (5-Aza) was determined. An additional 26 MSS colon cancers were assessed for ACVR2 loss and its mechanism, and ACVR2 loss in all tested cancers correlated with clinicopathological criteria. Results Of 51 MSS colon tumors, 7(14%) lost ACVR2, 2 (4%) ACVR1, and 5(10%) pSMAD2 expression. No somatic ACVR2 mutations were detected. Loss of ACVR2 expression was associated with LOH at ACVR2 (p<0.001) and ACVR2 promoter hypermethylation (p<0.05). ACVR2 LOH, but not promoter hypermethylation, correlated with CIN status. In colon cancer cell lines with fully methylated ACVR2 promoter, loss of ACVR2 mRNA and protein expression was restored with 5-Aza treatment. Loss of ACVR2 was associated with an increase in primary colon cancer volume (p<0.05). Conclusions Only a small percentage of MSS colon cancers lose expression of activin signaling members. ACVR2 loss occurs through LOH and ACVR2 promoter hypermethylation, revealing distinct mechanisms for ACVR2 inactivation in both MSI and MSS subtypes of colon cancer.