Benchmarking multi-ancestry prostate cancer polygenic risk scores in a real-world cohort.

Prostate cancer is a heritable disease with ancestry-biased incidence and mortality. Polygenic risk scores (PRSs) offer promising advancements in predicting disease risk, including prostate cancer. While their accuracy continues to improve, research aimed at enhancing their effectiveness within African and Asian populations remains key for equitable use. Recent algorithmic developments for PRS derivation have resulted in improved pan-ancestral risk prediction for several diseases. In this study, we benchmark the predictive power of six widely used PRS derivation algorithms, including four of which adjust for ancestry, against prostate cancer cases and controls from the UK Biobank and All of Us cohorts. We find modest improvement in discriminatory ability when compared with a simple method that prioritizes variants, clumping, and published polygenic risk scores. Our findings underscore the importance of improving upon risk prediction algorithms and the sampling of diverse cohorts.

Systematic evidence review and meta-analysis of outcomes associated with cancer genetic counseling.

PURPOSE: Genetic counseling (GC) is standard of care in genetic cancer risk assessment (GCRA). A rigorous assessment of the data reported from published studies is crucial to ensure the evidence-based implementation of GC. METHODS: We conducted a systematic review and meta-analysis of 17 patient-reported and health-services-related outcomes associated with pre- and post-test GC in GCRA in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. RESULTS: Twenty-five of 5393 screened articles met inclusion criteria. No articles reporting post-test GC outcomes met inclusion criteria. For patient-reported outcomes, pre-test GC significantly decreased worry, increased knowledge, and decreased perceived risk but did not significantly affect patient anxiety, depression, decisional conflict, satisfaction, or intent to pursue genetic testing. For health-services outcomes, pre-test GC increased correct genetic test ordering, reduced inappropriate services, increased spousal support for genetic testing, and expedited care delivery but did not consistently improve cancer prevention behaviors nor lead to accurate risk assessment. The GRADE certainty in the evidence was very low or low. No included studies elucidated GC effect on mortality, cascade testing, cost-effectiveness, care coordination, shared decision making, or patient time burden. CONCLUSION: The true impact of GC on relevant outcomes is not known low quality or absent evidence. Although a meta-analysis found that pre-test GC had beneficial effects on knowledge, worry, and risk perception, the certainty of this evidence was low according to GRADE methodology. Further studies are needed to support the evidence-based application of GC in GCRA.

Identifying factors and causal chains associated with optimal implementation of Lynch syndrome tumor screening: An application of coincidence analysis.

PURPOSE: This study compared Lynch syndrome universal tumor screening (UTS) across multiple health systems (some of which had two or more distinct UTS programs) to understand multi-level factors that may impact the successful implementation of complex programs. METHODS: Data from 66 stakeholder interviews were used to conduct multi-value coincidence analysis (mv-CNA) and identify key factors that consistently make a difference in whether UTS programs were implemented and optimized at the system level. RESULTS: The selected CNA model revealed combinations of conditions that distinguish 4 optimized UTS programs, 10 non-optimized programs, and 4 systems with no program. Fully optimized UTS programs had both a maintenance champion and a positive inner setting. Two independent paths were unique to non-optimized programs: 1) positive attitudes and a mixed inner setting, or 2) limited planning & engaging among stakeholders. Negative views about UTS evidence or lack of knowledge about UTS led to a lack of planning and engaging, which subsequently prevented program implementation. CONCLUSION: The model improved our understanding of program implementation in health care systems and informed the creation of a toolkit to guide UTS implementation, optimization, and changes. Our findings and toolkit may serve as a use case to increase the successful implementation of other complex precision health programs.

Integration and usability of a digital cancer risk stratification tool to optimize identification of patients at risk for hereditary cancers: A pilot study.

BACKGROUND: Patients with a personal or family history of cancer may have elevated risk of developing future cancers, which often remains unrecognized due to lapses in screening. This pilot study assessed the usability and clinical outcomes of a cancer risk stratification tool in a gynecologic oncology clinic. METHODS: New gynecologic oncology patients were prompted to complete a commercially developed personal and family history-based risk stratification tool to assess eligibility for genetic testing using National Comprehensive Cancer Network criteria and estimated lifetime breast cancer risk using the Tyrer-Cuzick model. After use of the risk stratification tool, usability was assessed via completion rate and the System Usability Scale, and health literacy was assessed using the BRIEF Health Literacy Screening Tool. RESULTS: 130 patients were prompted to complete the risk stratification tool; 93 (72%) completed the tool. Race and ethnicity and insurance type were not associated with tool completion. The median System Usability Scale score was 83 out of 100 (interquartile range, 60-95). Health literacy positively correlated with perceived usability. Public insurance and race or ethnicity other than non-Hispanic White was associated with lower perceived usability. Sixty (65%) patients met eligibility criteria for genetic testing, and 21 (38% of 56 eligible patients) were candidates for enhanced breast cancer screening based on an estimated lifetime breast cancer risk of ≥20%. CONCLUSIONS: A majority of patients completed the digital cancer risk stratification tool. Older age, lower health literacy, public insurance, and race or ethnicity other than non-Hispanic White were associated with lower perceived tool usability.

Personalized survivorship care: Routine breast cancer risk assessment in the gynecologic oncology clinic.

INTRODUCTION: Gynecologic and breast cancers share several risk factors. Breast cancer risk assessment tools can identify those at elevated risk and allow for enhanced breast surveillance and chemoprevention, however such tools are underutilized. We aim to evaluate the use of routine breast cancer risk assessment in a gynecologic oncology clinic. METHODS: A patient-facing web-based tool was used to collect personal and family history and run four validated breast cancer risk assessment models (Tyrer-Cuzick (TC), Gail, BRCAPRO, and Claus) in a gynecologic oncology clinic. We evaluated completion of the tools and identification of patients at elevated risk for breast cancer using the four validated models. RESULTS: A total of 99 patients were included in this analysis. The BRCAPRO model had the highest completion rate (84.8%), followed by the TC model (74.7%), Gail model (74.7%), and the Claus model (52.1%). The TC model identified 21.6% of patients completing the model as having ≥20% lifetime risk of breast cancer, compared to 6.8% by the Gail model, and 0% for both the BRCAPRO and Claus models. The Gail model identified 52.5% of patients as having ≥1.67% 5-year risk of breast cancer. Among patients identified as high-risk for breast cancer and eligible for screening, 9/9 (100%) were referred to a high-risk breast clinic. CONCLUSION: Among patients that completed the TC breast cancer risk assessment in a gynecologic oncology clinic, approximately 1 in 5 were identified to be at significantly elevated lifetime risk for breast cancer. The gynecologic oncologist's office might offer a convenient and feasible setting to incorporate this risk assessment into routine patient care, as gynecologic oncologists often have long-term patient relationships and participate in survivorship care.

Cost-effectiveness of BRCA1 testing at time of obstetrical prenatal carrier screening for cancer prevention.

BACKGROUND: Improved technologies paired with an increase in access to genetic testing have led to the availability of expanded carrier screening evaluating hundreds of disorders. Currently, most autosomal dominant mutations, such as BRCA1, are not included in expanded carrier assays. Screening pregnant or preconception reproductive-aged women for BRCA1 may present a unique opportunity to perform population-based screening for patients at a time when precancer screening, chemoprevention, and/or risk-reducing surgery may be beneficial. OBJECTIVE: This study aimed to inform clinical decision-making as to whether the universal incorporation of BRCA1 testing at the time of obstetrical prenatal carrier screening is cost-effective. STUDY DESIGN: A decision analysis and Markov model was created. The initial decision point in the model was BRCA1 testing at the time of expanded carrier screening. Model probabilities, cost, and utility values were derived from published literature. For BRCA1-positive patients, the model simulated breast cancer screening and risk-reducing surgical interventions. A cycle length of 1 year and a time horizon of 47 years were used to simulate the lifespan of patients. The setting was obstetrical clinics in the United States, and the participants were a theoretical cohort of 1,429,074 pregnant patients who annually underwent expanded carrier screening. RESULTS: Among our cohort, BRCA1 testing resulted in the identification of an additional 3716 BRCA1-positive patients, the prevention of 1394 breast and ovarian cancer cases, and 1084 fewer deaths. BRCA1 testing was a cost-effective strategy compared with no BRCA1 testing with an incremental cost-effectiveness ratio of $86,001 per quality-adjusted life years. In a 1-way sensitivity analysis, we varied the prevalence of BRCA1 in the population from 0.00% to 20.00% and found that BRCA1 testing continued to be the cost-effective strategy until the prevalence rate was reduced to 0.16%. Multiple additional sensitivity analyses did not substantially affect the cost-effectiveness. CONCLUSION: The addition of BRCA1 testing to obstetrical prenatal carrier screening is a cost-effective management strategy to identify at-risk women at a time when cancer screening and preventive strategies can be effective. Despite the burden of additional genetic counseling, prenatal care represents a unique opportunity to implement population-based genetic testing.

Partner and localizer of BRCA2 (PALB2) pathogenic variants and ovarian cancer: A systematic review and meta-analysis.

OBJECTIVE: Approximately 20% of ovarian cancers are due to an underlying germline pathogenic variant. While pathogenic variants in several genes have been well-established in the development of hereditary ovarian cancer (e.g. BRCA1/2, RAD51C, RAD51D, BRIP1, mismatch repair genes), the role of partner and localizer of BRCA2 (PALB2) remains uncertain. We sought to utilize meta-analysis to evaluate the association between PALB2 germline pathogenic variants and ovarian cancer. METHODS: We conducted a systematic review and meta-analysis. We searched key electronic databases to identify studies evaluating multigene panel testing in people with ovarian cancer. Eligible trials were subjected to meta-analysis. RESULTS: Fifty-five studies met inclusion criteria, including 48,194 people with ovarian cancer and information available on germline PALB2 pathogenic variant status. Among people with ovarian cancer and available PALB2 sequencing data, 0.4% [95% CI 0.3-0.4] harbored a germline pathogenic variant in the PALB2 gene. The pooled odds ratio (OR) for carrying a PALB2 pathogenic variant among the ovarian cancer population of 20,474 individuals who underwent germline testing was 2.48 [95% CI 1.57-3.90] relative to 123,883 controls. CONCLUSIONS: Our meta-analysis demonstrates that the pooled OR for harboring a PALB2 germline pathogenic variant among people with ovarian cancer compared to the general population is 2.48 [95% CI 1.57-3.90]. Prospective studies evaluating the role of germline PALB2 pathogenic variants in the development of ovarian cancer are warranted.

Web-based tool for cancer family history collection: A prospective randomized controlled trial.

OBJECTIVES: Approximately 1% of individuals have a hereditary cancer predisposition syndrome, however, the majority are not aware. Collecting a cancer family history (CFH) can triage patients to receive genetic testing. To rigorously assess different methods of CFH collection, we compared a web-based tool (WBT) to usual care (clinician collects CFH) in a randomized controlled trial. METHODS: New gynecologic oncology patients (seen 9/2019-9/2021) were randomized to one of three arms in a 2:2:1 allocation ratio: 1) usual care clinician CFH collection, 2) WBT completed at home, or 3) WBT completed in office. The WBT generated a cancer-focused pedigree and scores on eight validated cancer risk models. The primary outcome was collection of an adequate CFH (based on established guidelines) with usual care versus the WBT. RESULTS: We enrolled 250 participants (usual care - 110; WBT home - 105; WBT office - 35 [closed early due to COVID-19]). Within WBT arms, 109 (78%) participants completed the tool, with higher completion for office versus home (33 [94%] vs. 76 [72%], P = 0.008). Among participants completing the WBT, 63 (58%) had an adequate CFH versus 5 (5%) for usual care (P < 0.001). Participants completing the WBT were significantly more likely to complete genetic counseling (34 [31%] vs. 15 [14%], P = 0.002) and genetic testing (20 [18%] vs. 9 [8%], P = 0.029). Participant and provider WBT experience was favorable. CONCLUSIONS: WBTs for CFH collection are a promising application of health information technology, resulting in more comprehensive CFH and a significantly greater percentage of participants completing genetic counseling and testing.

"Go ahead and screen" - advice to healthcare systems for routine lynch syndrome screening from interviews with newly diagnosed colorectal cancer patients.

BACKGROUND: Lynch syndrome (LS) is the most common cause of inherited colorectal cancer (CRC). Universal tumor screening (UTS) of newly diagnosed CRC cases is recommended to aid in diagnosis of LS and reduce cancer-related morbidity and mortality. However, not all health systems have adopted UTS processes and implementation may be inconsistent due to system and patient-level complexities. METHODS: To identify barriers, facilitators, and suggestions for improvements of the UTS process from the patient perspective, we conducted in-depth, semi-structured interviews with patients recently diagnosed with CRC, but not screened for or aware of LS. Patients were recruited from eight regionally diverse US health systems. Interviews were conducted by telephone, 60-minutes, audio-recorded, and transcribed. An inductive, constant comparative analysis approach was employed.  RESULTS: We completed 75 interviews across the eight systems. Most participants were white (79%), about half (52%) were men, and the mean age was 60 years. Most self-reported either no (60%) or minimal (40%) prior awareness of LS. Overall, 96% of patients stated UTS should be a routine standard of care for CRC tumors, consistently citing four primary motivations for wanting to know their LS status and engage in the process for LS identification: "knowledge is power"; "family knowledge"; "prevention and detection"; and "treatment and surveillance." Common concerns pertaining to the process of screening for and identifying LS included: creating anticipatory worry for patients, the potential cost and the accuracy of the genetic test, and possibly having one's health insurance coverage impacted by the LS diagnosis. Patients suggested health systems communicate LS results in-person or by phone from a trained expert in LS; offer proactive verbal and written education about LS, the screening steps, and any follow-up surveillance recommendations; and support patients in communicating their LS screening to any of their blood relatives. CONCLUSION: Our qualitative findings demonstrate patients with CRC have a strong desire for healthcare systems to regularly implement and offer UTS. Patients offer key insights for health systems to guide future implementation and optimization of UTS and other LS screening programs and maximize diagnosis of individuals with LS and improve cancer-related surveillance and outcomes. TRIAL REGISTRATION: Not available: not a clinical trial.

What happens in the long term: Uptake of cancer surveillance and prevention strategies among at-risk relatives with pathogenic variants detected via cascade testing.

BACKGROUND: Cascade genetic testing for hereditary cancer syndromes offers affected relatives the opportunity to pursue cancer screening and risk-reducing surgery and thus reduces morbidity and mortality. The purpose of this study was to measure the long-term utilization of targeted cancer prevention and quality of life among at-risk relatives offered clinician-facilitated cascade genetic testing. METHODS: In a pilot study, at-risk relatives of patients with a hereditary cancer syndrome were contacted directly by the clinical team and offered telephone genetic counseling and genetic testing via an at-home, mailed saliva kit. Two-year follow-up results evaluating the use of targeted cancer prevention strategies and the quality of life for enrolled relatives were reported. Quality-of-life was measured with validated surveys, and scores were compared to the time of initial contact by the Wilcoxon signed-rank test. RESULTS: Ninety-five at-risk relatives were enrolled in the initial pilot study, and 72 (76%) participated in the 2-year follow-up; 57 of these (79%) had completed genetic testing. Twenty-five of those 57 relatives (44%) were found to harbor an inherited pathogenic variant. Guideline-based cancer surveillance was recommended to 18 relatives; 13 (72%) completed at least one recommended screening, and six (33%) completed all recommended screenings. Risk-reducing surgery was recommended to 10 relatives; four (40%) completed a total of eight procedures. Quality-of-life surveys demonstrated low levels of anxiety, depression, distress, and uncertainty. CONCLUSIONS: The 2-year follow-up of the original pilot study revealed that clinician-facilitated cascade testing resulted in genetically targeted cancer screening and prevention with preserved quality of life. These results, to be confirmed by larger randomized controlled trials, suggest that medical systems should consider supporting clinician-facilitated cascade testing programs.

Achieving universal genetic assessment for women with ovarian cancer: Are we there yet? A systematic review and meta-analysis.

PURPOSE: Several professional organizations recommend universal genetic assessment for people with ovarian cancer as identifying pathogenic variants can affect treatment, prognosis, and all-cause mortality for patients and relatives. We sought to evaluate the literature on genetic assessment for women with ovarian cancer and determine if any interventions or patient characteristics drive utilization of services. METHODS: We searched key electronic databases to identify trials that evaluated genetic assessment for people with ovarian cancer. Trials with the primary aim to evaluate utilization of genetic assessment with or without interventions were included. Eligible trials were subjected to meta-analysis and the moderating influence of health interventions on rates of genetic assessment were examined. RESULTS: A total of 35 studies were included (19 report on utilization of genetic services without an intervention, 7 with an intervention, and 9 with both scenarios). Without an intervention, pooled estimates for referral to genetic counseling and completion of genetic testing were 39% [CI 27-53%] and 30% [CI 19-44%]. Clinician-facilitated interventions included: mainstreaming of genetic services (99% [CI 86-100%]), telemedicine (75% [CI 43-93%]), clinic-embedded genetic counselor (76% [CI 32-95%]), reflex tumor somatic genetic assessment (64% [CI 17-94%]), universal testing (57% [28-82%]), and referral forms (26% [CI 10-53%]). Random-effects pooled proportions demonstrated that Black vs. White race was associated with a lower rate of genetic testing (26%[CI 17-38%] vs. 40% [CI 25-57%]) as was being un-insured vs. insured (23% [CI 18-28%] vs. 38% [CI 26-53%]). CONCLUSIONS: Reported rates of genetic testing for people with ovarian cancer remain well below the goal of universal testing. Interventions such as mainstreaming can improve testing uptake. Strategies aimed at improving utilization of genetic services should consider existing disparities in race and insurance status.

Somatic and germline sequencing in genitourinary oncology: genetics for the clinician.

PURPOSE OF REVIEW: Next-generation sequencing is becoming more accessible. This review focuses on the clinical application of somatic and germline sequencing to genitourinary oncology. RECENT FINDINGS: Germline variants have been increasingly recognized as contributing to the development of genitourinary malignancies, particularly in patients with advanced disease. A variety of commercial and institutional technologies are in use to detect variants, with newer tools focused on integrating these results into the clinical workflow. SUMMARY: DNA sequencing is becoming a valuable tool in caring for patients with genitourinary malignancies. Performing both somatic and germline sequencing will likely become standard practice. Interpretation and clinical application of these results can be challenging and often requires multidisciplinary expertise.

Implementing universal Lynch syndrome screening (IMPULSS): protocol for a multi-site study to identify strategies to implement, adapt, and sustain genomic medicine programs in different organizational contexts.

BACKGROUND: Systematic screening of all colorectal tumors for Lynch Syndrome (LS) has been recommended since 2009. Currently, implementation of LS screening in healthcare systems remains variable, likely because LS screening involves the complex coordination of multiple departments and individuals across the healthcare system. Our specific aims are to (1) describe variation in LS screening implementation across multiple healthcare systems; (2) identify conditions associated with both practice variation and optimal implementation; (3) determine the relative effectiveness, efficiency, and costs of different LS screening protocols by healthcare system; and (4) develop and test in a real-world setting an organizational toolkit for LS screening program implementation and improvement. This toolkit will promote effective implementation of LS screening in various complex health systems. METHODS: This study includes eight healthcare systems with 22 clinical sites at varied stages of implementing LS screening programs. Guided by the Consolidated Framework for Implementation Research (CFIR), we will conduct in-depth semi-structured interviews with patients and organizational stakeholders and perform economic evaluation of site-specific implementation costs. These processes will result in a comprehensive cross-case analysis of different organizational contexts. We will utilize qualitative data analysis and configurational comparative methodology to identify facilitators and barriers at the organizational level that are minimally sufficient and necessary for optimal LS screening implementation. DISCUSSION: The overarching goal of this project is to combine our data with theories and tools from implementation science to create an organizational toolkit to facilitate implementation of LS screening in various real-world settings. Our organizational toolkit will account for issues of complex coordination of care involving multiple stakeholders to enhance implementation, sustainability, and ongoing improvement of evidence-based LS screening programs. Successful implementation of such programs will ultimately reduce suffering of patients and their family members from preventable cancers, decrease waste in healthcare system costs, and inform strategies to facilitate the promise of precision medicine. TRIAL REGISTRATION: N/A.

Population-Level Identification of Patients With Lynch Syndrome for Clinical Care, Quality Improvement, and Research.

PURPOSE: Identification of those at risk of hereditary cancer syndromes using electronic health record (EHR) data sources is important for clinical care, quality improvement, and research. We describe diagnostic processes, previously seldom reported, for a common hereditary cancer syndrome, Lynch syndrome (LS), using EHR data within a community-based, multicenter, demographically diverse health system. METHODS: Within a retrospective cohort enrolled between 2015 and 2020 at Kaiser Permanente Northern California, we assessed electronic diagnostic domains for LS including (1) family history of LS-associated cancer; (2) personal history of LS-associated cancer; (3) LS screening via mismatch repair deficiency (MMRD) testing of newly diagnosed malignancy; (4) germline genetic test results; and (5) clinician-entered diagnostic codes for LS. We calculated proportions and overlap for each diagnostic domain descriptively. RESULTS: Among 5.8 million individuals, (1) 28,492 (0.49%) had a family history of LS-associated cancer of whom 3,635 (13%) underwent genetic testing; (2) 100,046 (1.7%) had a personal history of a LS-associated cancer; and (3) 8,711 (0.1%) were diagnosed with colorectal cancer of whom 7,533 (86%) underwent MMRD screening and of the positive screens (486), 130 (27%) underwent germline testing. One thousand seven hundred and fifty-seven (0.03%) were diagnosed with endometrial cancer of whom 1,613 (92%) underwent MMRD screening and of the 195 who screened positive, 55 (28%) underwent genetic testing. (4) 30,790 (0.05%) had LS germline genetic testing with 707 (0.01%) testing positive; and (5) 1,273 (0.02%) had a clinician-entered diagnosis of LS. CONCLUSION: It is feasible to electronically characterize the diagnostic processes of LS. No single data source comprehensively identifies all LS carriers. There is underutilization of LS genetic testing for those eligible and underdiagnosis of LS. Our work informs similar efforts in other settings for hereditary cancer syndromes.

Uptake of genetic testing by relatives of lynch syndrome probands: a systematic review.

BACKGROUND & AIMS: Screening of persons with newly diagnosed colorectal cancer for Lynch syndrome can yield substantial benefits at acceptable costs, presuming sufficient uptake of genetic testing by first-degree relatives of Lynch syndrome probands. We performed a systematic review of the literature to determine the frequency of and factors associated with genetic testing of first-degree relatives of Lynch syndrome probands. METHODS: We searched 4 databases (CINAHL, PsycInfo, PUBMED, and SCOPUS) for articles published through May 2011 reporting uptake of genetic testing by relatives of Lynch syndrome probands. Two investigators independently screened articles to determine whether they met inclusion criteria; data were collected on study population, genetic counseling, and genetic testing. A narrative, qualitative systematic review was performed. RESULTS: We identified 1258 potentially relevant articles; 533 underwent full-text review, and 8 were included in the final analysis. Of first-degree relatives of Lynch syndrome probands, 52% or less received genetic testing. For each proband, 3.6 or fewer relatives underwent genetic testing. Demographic factors (age <50 years, female sex, parenthood, level of education, employment, participation in medical studies), psychological factors (lack of depressive symptoms), and possibly family history (greater number of relatives with cancer) were associated with uptake of genetic testing. CONCLUSIONS: Genetic testing appears to be underutilized by first-degree relatives of patients with Lynch syndrome. The clinical benefit and economic feasibility of screening persons with colorectal cancer for Lynch syndrome depend on optimizing family-wide uptake of genetic testing. Future research and clinical efforts should focus on ways to overcome barriers to genetic testing.

Comparative effectiveness and cost-effectiveness of screening colonoscopy vs. sigmoidoscopy and alternative strategies.

OBJECTIVES: Fecal occult blood testing (FOBT) and sigmoidoscopy are proven to decrease colorectal cancer (CRC) incidence and mortality. Sigmoidoscopy's benefit is limited to the distal colon. Observational data are conflicting regarding the degree to which colonoscopy affords protection against proximal CRC. Our aim was to explore the comparative effectiveness and cost-effectiveness of colonoscopy vs. sigmoidoscopy and alternative CRC screening strategies in light of the latest published data. METHODS: We performed a contemporary cost-utility analysis using a Markov model validated against data from randomized controlled trials of FOBT and sigmoidoscopy. Persons at average CRC risk within the general US population were modeled. Screening strategies included those recommended by the United States (US) Preventive Services Task Force, including colonoscopy every 10 years (COLO), flexible sigmoidoscopy every 5 years (FS), annual fecal occult blood testing, annual fecal immunochemical testing (FIT), and the combination FS/FIT. The main outcome measures were quality-adjusted life-years (QALYs) and costs. RESULTS: In the base case, FIT dominated other strategies. The advantage of FIT over FS and COLO was contingent on rates of uptake and adherence that are well above current US rates. Compared with FIT, FS and COLO both cost <$50,000/QALY gained when FIT per-cycle adherence was <50%. COLO cost $56,800/QALY gained vs. FS in the base case. COLO cost <$100,000/QALY gained vs. FS when COLO yielded a relative risk of proximal CRC of <0.5 vs. no screening. In probabilistic analyses, COLO was cost-effective vs. FS at a willingness-to-pay threshold of $100,000/QALY gained in 84% of iterations. CONCLUSIONS: Screening colonoscopy may be cost-effective compared with FIT and sigmoidoscopy, depending on the relative rates of screening uptake and adherence and the protective benefit of colonoscopy in the proximal colon. Colonoscopy's cost-effectiveness compared with sigmoidoscopy is contingent on the ability to deliver ~50% protection against CRC in the proximal colon.