Rates of Downstream Procedures and Complications Associated With Lung Cancer Screening in Routine Clinical Practice : A Retrospective Cohort Study

BACKGROUND

Lung cancer screening (LCS) using low-dose computed tomography (LDCT) reduces lung cancer mortality but can lead to downstream procedures, complications, and other potential harms. Estimates of these events outside NLST (National Lung Screening Trial) have been variable and lacked evaluation by screening result, which allows more direct comparison with trials.

OBJECTIVE

To identify rates of downstream procedures and complications associated with LCS.

DESIGN

Retrospective cohort study.

SETTING

5 U.S. health care systems.

PATIENTS

Individuals who completed a baseline LDCT scan for LCS between 2014 and 2018.

MEASUREMENTS

Outcomes included downstream imaging, invasive diagnostic procedures, and procedural complications. For each, absolute rates were calculated overall and stratified by screening result and by lung cancer detection, and positive and negative predictive values were calculated.

RESULTS

Among the 9266 screened patients, 1472 (15.9%) had a baseline LDCT scan showing abnormalities, of whom 140 (9.5%) were diagnosed with lung cancer within 12 months (positive predictive value, 9.5% [95% CI, 8.0% to 11.0%]; negative predictive value, 99.8% [CI, 99.7% to 99.9%]; sensitivity, 92.7% [CI, 88.6% to 96.9%]; specificity, 84.4% [CI, 83.7% to 85.2%]). Absolute rates of downstream imaging and invasive procedures in screened patients were 31.9% and 2.8%, respectively. In patients undergoing invasive procedures after abnormal findings, complication rates were substantially higher than those in NLST (30.6% vs. 17.7% for any complication; 20.6% vs. 9.4% for major complications).

LIMITATION

Assessment of outcomes was retrospective and was based on procedural coding.

CONCLUSION

The results indicate substantially higher rates of downstream procedures and complications associated with LCS in practice than observed in NLST. Diagnostic management likely needs to be assessed and improved to ensure that screening benefits outweigh potential harms.

PRIMARY FUNDING SOURCE

National Cancer Institute and Gordon and Betty Moore Foundation.

Risk of Colorectal Cancer and Colorectal Cancer Mortality Beginning One Year after a Negative Fecal Occult Blood Test, among Screen-Eligible 76- to 85-Year-Olds

BACKGROUND

Colorectal cancer screening is universally recommended for adults ages 45 to 75 years. Noninvasive fecal occult blood tests are effective screening tests recommended by guidelines. However, empirical evidence to inform older adults' decisions about whether to continue screening is sparse, especially for individuals with prior screening.

METHODS

This study used a retrospective cohort of older adults at three Kaiser Permanente integrated healthcare systems (Northern California, Southern California, Washington) and Parkland Health. Beginning 1 year following a negative stool-based screening test, cumulative risks of colorectal cancer incidence, colorectal cancer mortality (accounting for deaths from other causes), and non-colorectal cancer mortality were estimated.

RESULTS

Cumulative incidence of colorectal cancer in screen-eligible adults ages 76 to 85 with a negative fecal occult blood test 1 year ago (N = 118,269) was 0.23% [95% confidence interval (CI), 0.20%-0.26%] after 2 years and 1.21% (95% CI, 1.13%-1.30%) after 8 years. Cumulative colorectal cancer mortality was 0.03% (95% CI, 0.02%-0.04%) after 2 years and 0.33% (95% CI, 0.28%-0.39%) after 8 years. Cumulative risk of death from non-colorectal cancer causes was 4.81% (95% CI, 4.68%-4.96%) after 2 years and 28.40% (95% CI, 27.95%-28.85%) after 8 years.

CONCLUSIONS

Among 76- to 85-year-olds with a recent negative stool-based test, cumulative colorectal cancer incidence and mortality estimates were low, especially within 2 years; death from other causes was over 100 times more likely than death from colorectal cancer.

IMPACT

These findings of low absolute colorectal cancer risk, and comparatively higher risk of death from other causes, can inform decision-making regarding whether and when to continue colorectal cancer screening beyond age 75 among screen-eligible adults.

Outcomes From More Than 1 Million People Screened for Lung Cancer With Low-Dose CT Imaging

BACKGROUND

Lung cancer screening (LCS) with low-dose CT (LDCT) imaging was recommended in 2013, making approximately 8 million Americans eligible for LCS. The demographic characteristics and outcomes of individuals screened in the United States have not been reported at the population level.

RESEARCH QUESTION

What are the outcomes among people screened and entered in the American College of Radiology's Lung Cancer Screening Registry compared with those of trial participants?

STUDY DESIGN AND METHODS

This was a cohort study of individuals undergoing baseline LDCT imaging for LCS between 201 and 2019. Predictors of adherence to annual screening were computed. LDCT scan interpretations by Lung Imaging Reporting and Data System (Lung-RADS) score, cancer detection rates (CDRs), and stage at diagnosis were compared with National Lung Cancer Screening Trial (NLST) data.

RESULTS

Adherence was 22.3%, and predictors of poor adherence included current smoking status and Hispanic or Black race. On baseline screening, 83% of patients showed negative results and 17% showed positive screening results. The overall CDR was 0.56%. The percentage of people with cancer detected at baseline was higher in the positive Lung-RADS categories at 0.4% for Lung-RADS category 3, 2.6% for Lung-RADS category 4A, 11.1% for Lung-RADS category 4B, and 19.9% for Lung-RADS category 4X. The cancer stage distribution was similar to that observed in the NLST, with 53.5% of patients receiving a diagnosis of stage I cancer and 14.3% with stage IV cancer. Underreporting into the registry may have occurred.

INTERPRETATION

This study revealed both the positive aspects of CT scan screening for lung cancer and the challenges that remain. Findings on CT imaging were correlated accurately with lung cancer detection using the Lung-RADS system. A significant stage shift toward early-stage lung cancer was present. Adherence to LCS was poor and likely contributes to the lower than expected cancer detection rate, all of which will impact the outcomes of patients undergoing screening for lung cancer.

Test performance metrics for breast, cervical, colon and lung cancer screening: a systematic review

BACKGROUND

Multiple quality metrics have been recommended to ensure consistent, high-quality execution of screening tests for breast, cervical, colorectal and lung cancers. However, minimal data exist evaluating the evidence base supporting these recommendations and the consistency of definitions and concepts included within and between cancer types.

METHODS

We performed a systematic review for each cancer type using MEDLINE, Embase and CINAHL from 2010 to April 2020, to identify guidelines from screening programs or professional organizations containing quality metrics for tests used in breast, cervical, colorectal and lung cancer screening. We abstracted metrics' definitions, target performance levels, and related supporting evidence for test completeness, adequacy (sufficient visualization or collection), accuracy, and safety.

RESULTS

We identified 11 relevant guidelines with 20 suggested quality metrics for breast cancer, 5 guidelines with 9 metrics for cervical cancer, 13 guidelines with 18 metrics for colorectal cancer, and 3 guidelines with 7 metrics for lung cancer. These included 54 metrics related to adequacy (6), test completeness (3), accuracy (33), and safety (12). Target performance levels were defined for 30 metrics (56%). Ten (19%) were supported by evidence, all from breast and colorectal cancer, with no evidence cited to support metrics from cervical and lung cancer screening.

CONCLUSIONS

Considerably more guideline-recommended test performance metrics exist for breast and colorectal cancer screening than cervical or lung cancer. The domains covered are inconsistent among cancers and few targets are supported by evidence. Clearer evidence-based domains and targets are needed for test performance metrics.

REGISTRATION

PROSPERO 2020 CRD42020179139.

Characteristics of Persons Screened for Lung Cancer in the United States : A Cohort Study

BACKGROUND

Lung cancer screening (LCS) with low-dose computed tomography (LDCT) was recommended by the U.S. Preventive Services Task Force (USPSTF) in 2013, making approximately 8 million Americans eligible for screening. The demographic characteristics and adherence of persons screened in the United States have not been reported at the population level.

OBJECTIVE

To define sociodemographic characteristics and adherence among persons screened and entered into the American College of Radiology's Lung Cancer Screening Registry (LCSR).

DESIGN

Cohort study.

SETTING

United States, 2015 to 2019.

PARTICIPANTS

Persons receiving a baseline LDCT for LCS from 3625 facilities reporting to the LCSR.

MEASUREMENTS

Age, sex, and smoking status distributions (percentages) were computed among persons who were screened and among respondents in the 2015 National Health Interview Survey (NHIS) who were eligible for screening. The prevalence between the LCSR and the NHIS was compared with prevalence ratios (PRs) and 95% CIs. Adherence to annual screening was defined as having a follow-up test within 11 to 15 months of an initial LDCT.

RESULTS

Among 1 159 092 persons who were screened, 90.8% (n = 1 052 591) met the USPSTF eligibility criteria. Compared with adults from the NHIS who met the criteria (n = 1257), screening recipients in the LCSR were older (34.7% vs. 44.8% were aged 65 to 74 years; PR, 1.29 [95% CI, 1.20 to 1.39]), more likely to be female (41.8% vs. 48.1%; PR, 1.15 [CI, 1.08 to 1.23]), and more likely to currently smoke (52.3% vs. 61.4%; PR, 1.17 [CI, 1.11 to 1.23]). Only 22.3% had a repeated annual LDCT. If follow-up was extended to 24 months and more than 24 months, 34.3% and 40.3% were adherent, respectively.

LIMITATIONS

Underreporting of LCS and missing data may skew demographic characteristics of persons reported to be screened. Underreporting of adherence may result in underestimates of follow-up.

CONCLUSION

Approximately 91% of persons who had LCS met USPSTF eligibility criteria. In addition to continuing to target all eligible adults, men, those who formerly smoked, and younger eligible patients may be less likely to be screened. Adherence to annual follow-up screening was poor, potentially limiting screening effectiveness.

PRIMARY FUNDING SOURCE

None.

Evaluation of Harms Reporting in U.S. Cancer Screening Guidelines

BACKGROUND

Cancer screening should be recommended only when the balance between benefits and harms is favorable. This review evaluated how U.S. cancer screening guidelines reported harms, within and across organ-specific processes to screen for cancer.

OBJECTIVE

To describe current reporting practices and identify opportunities for improvement.

DESIGN

Review of guidelines.

SETTING

United States.

PATIENTS

Patients eligible for screening for breast, cervical, colorectal, lung, or prostate cancer according to U.S. guidelines.

MEASUREMENTS

Information was abstracted on reporting of patient-level harms associated with screening, diagnostic follow-up, and treatment. The authors classified harms reporting as not mentioned, conceptual, qualitative, or quantitative and noted whether literature was cited when harms were described. Frequency of harms reporting was summarized by organ type.

RESULTS

Harms reporting was inconsistent across organ types and at each step of the cancer screening process. Guidelines did not report all harms for any specific organ type or for any category of harm across organ types. The most complete harms reporting was for prostate cancer screening guidelines and the least complete for colorectal cancer screening guidelines. Conceptualization of harms and use of quantitative evidence also differed by organ type.

LIMITATIONS

This review considers only patient-level harms. The authors did not verify accuracy of harms information presented in the guidelines.

CONCLUSION

The review identified opportunities for improving conceptualization, assessment, and reporting of screening process-related harms in guidelines. Future work should consider nuances associated with each organ-specific process to screen for cancer, including which harms are most salient and where evidence gaps exist, and explicitly explore how to optimally weigh available evidence in determining net screening benefit. Improved harms reporting could aid informed decision making, ultimately improving cancer screening delivery.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Evaluating and Improving Cancer Screening Process Quality in a Multilevel Context: The PROSPR II Consortium Design and Research Agenda

BACKGROUND

Cancer screening is a complex process involving multiple steps and levels of influence (e.g., patient, provider, facility, health care system, community, or neighborhood). We describe the design, methods, and research agenda of the Population-based Research to Optimize the Screening Process (PROSPR II) consortium. PROSPR II Research Centers (PRC), and the Coordinating Center aim to identify opportunities to improve screening processes and reduce disparities through investigation of factors affecting cervical, colorectal, and lung cancer screening in U.S. community health care settings.

METHODS

We collected multilevel, longitudinal cervical, colorectal, and lung cancer screening process data from clinical and administrative sources on >9 million racially and ethnically diverse individuals across 10 heterogeneous health care systems with cohorts beginning January 1, 2010. To facilitate comparisons across organ types and highlight data breadth, we calculated frequencies of multilevel characteristics and volumes of screening and diagnostic tests/procedures and abnormalities.

RESULTS

Variations in patient, provider, and facility characteristics reflected the PROSPR II health care systems and differing target populations. PRCs identified incident diagnoses of invasive cancers, in situ cancers, and precancers (invasive: 372 cervical, 24,131 colorectal, 11,205 lung; in situ: 911 colorectal, 32 lung; precancers: 13,838 cervical, 554,499 colorectal).

CONCLUSIONS

PROSPR II's research agenda aims to advance: (i) conceptualization and measurement of the cancer screening process, its multilevel factors, and quality; (ii) knowledge of cancer disparities; and (iii) evaluation of the COVID-19 pandemic's initial impacts on cancer screening. We invite researchers to collaborate with PROSPR II investigators.

IMPACT

PROSPR II is a valuable data resource for cancer screening researchers.

A History of Health Economics and Healthcare Delivery Research at the National Cancer Institute

With increased attention to the financing and structure of healthcare, dramatic increases in the cost of diagnosing and treating cancer, and corresponding disparities in access, the study of healthcare economics and delivery has become increasingly important. The Healthcare Delivery Research Program (HDRP) in the Division of Cancer Control and Population Sciences at the National Cancer Institute (NCI) was formed in 2015 to provide a hub for cancer-related healthcare delivery and economics research. However, the roots of this program trace back much farther, at least to the formation of the NCI Division of Cancer Prevention and Control in 1983. The creation of a division focused on understanding and explaining trends in cancer morbidity and mortality was instrumental in setting the direction of cancer-related healthcare delivery and health economics research over the subsequent decades. In this commentary, we provide a brief history of health economics and healthcare delivery research at NCI, describing the organizational structure and highlighting key initiatives developed by the division, and also briefly discuss future directions. HDRP and its predecessors have supported the growth and evolution of these fields through the funding of grants and contracts; the development of data, tools, and other research resources; and thought leadership including stimulation of research on previously understudied topics. As the availability of new data, methods, and computing capacity to evaluate cancer-related healthcare delivery and economics expand, HDRP aims to continue to support this growth and evolution.

Screening for Colorectal Cancer in the United States: Correlates and Time Trends by Type of Test

BACKGROUND

It is strongly recommended that adults aged 50-75 years be screened for colorectal cancer. Recommended screening options include colonoscopy, sigmoidoscopy, CT colonography, guaiac fecal occult blood testing (FOBT), fecal immunochemical testing (FIT), or the more recently introduced FIT-DNA (FIT in combination with a stool DNA test). Colorectal cancer screening programs can benefit from knowledge of patterns of use by test type and within population subgroups.

METHODS

Using 2018 National Health Interview Survey (NHIS) data, we examined colorectal cancer screening test use for adults aged 50-75 years (N = 10,595). We also examined time trends in colorectal cancer screening test use from 2010-2018.

RESULTS

In 2018, an estimated 66.9% of U.S. adults aged 50-75 years had a colorectal cancer screening test within recommended time intervals. However, the prevalence was less than 50% among those aged 50-54 years, those without a usual source of health care, those with no doctor visits in the past year, and those who were uninsured. The test types most commonly used within recommended time intervals were colonoscopy within 10 years (61.1%), FOBT or FIT in the past year (8.8%), and FIT-DNA within 3 years (2.7%). After age-standardization to the 2010 census population, the percentage up-to-date with CRC screening increased from 61.2% in 2015 to 65.3% in 2018, driven by increased use of stool testing, including FIT-DNA.

CONCLUSIONS

These results show some progress, driven by a modest increase in stool testing. However, colorectal cancer testing remains low in many population subgroups.

IMPACT

These results can inform efforts to achieve population colorectal cancer screening goals.

Colorectal Cancer Screening: An Updated Modeling Study for the US Preventive Services Task Force

Importance

The US Preventive Services Task Force (USPSTF) is updating its 2016 colorectal cancer screening recommendations.

Objective

To provide updated model-based estimates of the benefits, burden, and harms of colorectal cancer screening strategies and to identify strategies that may provide an efficient balance of life-years gained (LYG) from screening and colonoscopy burden to inform the USPSTF.

Design, Setting, and Participants

Comparative modeling study using 3 microsimulation models of colorectal cancer screening in a hypothetical cohort of 40-year-old US individuals at average risk of colorectal cancer.

Exposures

Screening from ages 45, 50, or 55 years to ages 70, 75, 80, or 85 years with fecal immunochemical testing (FIT), multitarget stool DNA testing, flexible sigmoidoscopy alone or with FIT, computed tomography colonography, or colonoscopy. All persons with an abnormal noncolonoscopy screening test result were assumed to undergo follow-up colonoscopy. Screening intervals varied by test. Full adherence with all procedures was assumed.

Main Outcome and Measures

Estimated LYG relative to no screening (benefit), lifetime number of colonoscopies (burden), number of complications from screening (harms), and balance of incremental burden and benefit (efficiency ratios). Efficient strategies were those estimated to require fewer additional colonoscopies per additional LYG relative to other strategies.

Results

Estimated LYG from screening strategies ranged from 171 to 381 per 1000 40-year-olds. Lifetime colonoscopy burden ranged from 624 to 6817 per 1000 individuals, and screening complications ranged from 5 to 22 per 1000 individuals. Among the 49 strategies that were efficient options with all 3 models, 41 specified screening beginning at age 45. No single age to end screening was predominant among the efficient strategies, although the additional LYG from continuing screening after age 75 were generally small. With the exception of a 5-year interval for computed tomography colonography, no screening interval predominated among the efficient strategies for each modality. Among the strategies highlighted in the 2016 USPSTF recommendation, lowering the age to begin screening from 50 to 45 years was estimated to result in 22 to 27 additional LYG, 161 to 784 additional colonoscopies, and 0.1 to 2 additional complications per 1000 persons (ranges are across screening strategies, based on mean estimates across models). Assuming full adherence, screening outcomes and efficient strategies were similar by sex and race and across 3 scenarios for population risk of colorectal cancer.

Conclusions and Relevance

This microsimulation modeling analysis suggests that screening for colorectal cancer with stool tests, endoscopic tests, or computed tomography colonography starting at age 45 years provides an efficient balance of colonoscopy burden and life-years gained.

The National Cancer Institute's Role in Advancing Health-care Delivery Research

Improvements in cancer care delivery have the potential to reduce morbidity and mortality from cancer, however challenges to delivery of recommended care limit progress. These challenges include growing demands for care, increasing treatment complexity, inadequate care coordination, dramatic increases in costs, persistent disparities in care, and insufficient use of evidence-based guidelines. Recognizing the important role of research in understanding and addressing these challenges, the National Cancer Institute created the Healthcare Delivery Research Program (HDRP) in 2015 as a catalyst for expanding work in this area. Health-care delivery research is a multidisciplinary effort which recognizes that care delivery occurs in a multilevel system encompassing individuals, health-care systems, and communities. HDRP staff use a range of activities to fulfill the program's mission of advancing innovative research to improve delivery of care across the cancer control continuum. In addition to developing funding opportunities, HDRP staff support and facilitate the use of research infrastructure for conducting health-care delivery research, oversee publicly available data that can be used to evaluate patterns, costs, and patient experiences of care, contribute to development and dissemination of standardized health measurement tools for public use, and support professional development and training to build capacity within the field and grow the workforce. As HDRP enters its sixth year, we appreciate the opportunity to reflect on the program's progress in advancing the science of health-care delivery. At the same time, we recognize the need for the program to evolve and develop additional resources and opportunities to address new and emerging challenges.

Measures of longitudinal adherence to fecal-based colorectal cancer screening: Literature review and recommended approaches

The success of fecal occult blood-based colorectal cancer screening programs is dependent on repeating screening at short intervals (ie, every 1-2 years). We conducted a literature review to assess measures that have been used to assess longitudinal adherence to fecal-based screening. Among 46 citations identified and included in this review, six broad classifications of longitudinal adherence were identified: (a) stratified single-round attendance, (b) all possible adherence permutations, (c) consistent/inconsistent/never attendance, (d) number of times attended, (e) program adherence and (f) proportion of time covered. Advantages and disadvantages of these measures are described, and recommendations on which measures to use based on data availability and scientific question are also given. Stratified single round attendance is particularly useful for describing the yield of screening, while programmatic adherence measures are best suited to evaluating screening efficacy. We recommend that screening programs collect detailed longitudinal, individual-level data, not only for the screening tests themselves but additionally for diagnostic follow-up and surveillance exams, to allow for maximum flexibility in reporting adherence patterns using the measure of choice.

Evaluating Screening Participation, Follow-up, and Outcomes for Breast, Cervical, and Colorectal Cancer in the PROSPR Consortium

BACKGROUND

Cancer screening is a complex process encompassing risk assessment, the initial screening examination, diagnostic evaluation, and treatment of cancer precursors or early cancers. Metrics that enable comparisons across different screening targets are needed. We present population-based screening metrics for breast, cervical, and colorectal cancers for nine sites participating in the Population-based Research Optimizing Screening through Personalized Regimens consortium.

METHODS

We describe how selected metrics map to a trans-organ conceptual model of the screening process. For each cancer type, we calculated calendar year 2013 metrics for the screen-eligible target population (breast: ages 40-74 years; cervical: ages 21-64 years; colorectal: ages 50-75 years). Metrics for screening participation, timely diagnostic evaluation, and diagnosed cancers in the screened and total populations are presented for the total eligible population and stratified by age group and cancer type.

RESULTS

The overall screening-eligible populations in 2013 were 305 568 participants for breast, 3 160 128 for cervical, and 2 363 922 for colorectal cancer screening. Being up-to-date for testing was common for all three cancer types: breast (63.5%), cervical (84.6%), and colorectal (77.5%). The percentage of abnormal screens ranged from 10.7% for breast, 4.4% for cervical, and 4.5% for colorectal cancer screening. Abnormal breast screens were followed up diagnostically in almost all (96.8%) cases, and cervical and colorectal were similar (76.2% and 76.3%, respectively). Cancer rates per 1000 screens were 5.66, 0.17, and 1.46 for breast, cervical, and colorectal cancer, respectively.

CONCLUSIONS

Comprehensive assessment of metrics by the Population-based Research Optimizing Screening through Personalized Regimens consortium enabled systematic identification of screening process steps in need of improvement. We encourage widespread use of common metrics to allow interventions to be tested across cancer types and health-care settings.

Abstract IA23: Opportunities and lessons learned from the Cancer Research Network

Using health care systems data for research and care improvement is of intense interest. The now widespread availability of electronic health records (EHRs) holds great promise for population sciences cancer research. Founded in 1999, the Cancer Research Network (CRN) is a consortium of a dozen research groups affiliated with US integrated health care systems. CRN health care systems are pioneers in use of data systems to document and inform administrative and clinical aspects of health care. In addition to administrative (e.g., claims) data, the clinical databases of CRN health systems capture details of care that have generally not been available until the advent of EHRs. In most CRN health systems, such databases have been in use since at least the mid-1990s, with adoption of EHRs in the mid-2000s. CRN researchers developed the Virtual Data Warehouse (VDW) common data model to facilitate collaborative, multi-institution research. The VDW, with standardized data tables, variable names, and formats implemented at each participating research group, enables efficient multi-institution research collaborations. From a cancer research perspective, the VDW is also one of the only EHR-based common data models with tumor registry data of comparable quality to that of the SEER Program. Infusion medication data are also available in the VDW, and inclusion of results of clinical genetic and molecular tests is in development. The VDW is updated regularly, monthly or more frequently in most CRN institutions for most data domains. Advantages of conducting cancer research in the CRN setting include the ability to identify a “denominator” population, and the capture of primary and specialty care. Retention of health plan enrollees is high in CRN health systems, enabling longitudinal research. In most US health care settings, the population eligible to receive care cannot be identified, and data may be available for some, but not all, episodes of care. For example, tertiary-care cancer centers may have details on cancer treatment, but not information from primary care or other specialty care encounters. However, it is important to use caution because EHR data result from clinical encounters and associated activity and are not collected for research purposes; missingness is unlikely to be random and confounding by indication is an analytic and interpretational issue. Collaborative, efficient use of these data also requires navigating regulatory concerns. The federated nature of the VDW minimizes HIPAA-related privacy concerns, while agreed-upon human subjects and data use procedures facilitate collaborations. The CRN provides unparalleled opportunities for research across the full range of the cancer experience, from primary prevention to end of life, incorporating data from EHRs and other clinical and administrative databases. Use of these data and adherence to epidemiologic principles in the design of studies and their analysis and interpretation can greatly advance knowledge to decrease the burden of cancer.

Citation Format: Lawrence H. Kushi, Jeffrey S. Brown, Diana S.M. Buist, Jessica Chubak, V. Paul Doria-Rose, Kathleen M. Mazor. Opportunities and lessons learned from the Cancer Research Network [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr IA23.

The effect of using fecal testing after a negative sigmoidoscopy on the risk of death from colorectal cancer

OBJECTIVE

To examine whether receiving a fecal occult blood test after a negative sigmoidoscopy reduced mortality from colorectal cancer.

METHODS

We used a nested case-control design with incidence-density matching in historical cohorts of 1,877,740 50-90-year-old persons during 2006-2012, in an integrated health-system setting. We selected 1758 average risk patients who died from colorectal cancer and 3503 matched colorectal cancer-free persons. Colorectal cancer-specific death was ascertained from cancer and mortality registries. Screening histories were determined from electronic and chart-audit clinical data in the 5- to 10-year period prior to the reference date. We evaluated receipt of subsequent fecal occult blood test within five years of the reference date among patients with negative sigmoidoscopy two to six years before the reference date.

RESULTS

Of the 5261 patients, 831 patients (204 colorectal cancer deaths/627 controls) had either negative sigmoidoscopy only (n = 592) or negative sigmoidoscopy with subsequent screening fecal occult blood test (n = 239). Fifty-six (27.5%) of the 204 patients dying of colorectal cancer and 183 (29.2%) of the 627 colorectal cancer-free patients received fecal occult blood test following a negative sigmoidoscopy. Conditional regressions found no significant association between fecal occult blood test receipt and colorectal cancer death risk, overall (adjusted odds ratio = 0.93, confidence interval: 0.65-1.33), or for right (odds ratio = 1.02, confidence interval: 0.65-1.60) or left-colon/rectum (odds ratio = 0.77, confidence interval: 0.39-1.52) cancers. Similar results were obtained in sensitivity analyses with alternative exposure ascertainment windows or timing of fecal occult blood test.

CONCLUSIONS

Our results suggest that receipt of at least one fecal occult blood test during the several years after a negative sigmoidoscopy did not substantially reduce mortality from colorectal cancer.

Evaluating Lung Cancer Screening Uptake, Outcomes, and Costs in the United States: Challenges With Existing Data and Recommendations for Improvement

The National Lung Screening Trial (NLST) reported substantial reduction in lung cancer mortality among high-risk individuals screened annually with low-dose helical computed tomography (LDCT). As a result, the US Preventive Services Task Force issued a B recommendation for annual LDCT in high-risk individuals, which requires private insurers to cover it without cost-sharing. The Medicare program also covers LDCT for high-risk beneficiaries without cost-sharing. However, the NLST findings may not be generalizable to the community setting because of differences in patients, providers, and practices participating in the NLST. Thus, examining uptake of LDCT screening in community practice is critical, as is evaluating the immediate and downstream outcomes of screening, including false-positive scans, follow-up examinations and adverse events, costs, stage of disease at diagnosis, and survival. This commentary presents an overview of the landscape of the data resources currently available to evaluate the uptake, outcomes, and costs of LDCT screening in the United States. We describe the strengths and limitations of existing data sources, including administrative databases, surveys, and registries. Thereafter, we provide recommendations for improving the data infrastructure pertaining to three overarching research areas: receipt of guideline-consistent screening and follow-up, weighing benefits and harms of screening, and costs of screening.

Accuracy of Self-reported Colonic Polyps: Results from the Prostate, Lung, Colorectal, and Ovarian Screening Trial Study of Colonoscopy Utilization

BACKGROUND

Colonoscopy follow-up recommendations depend on the presence or absence of polyps, and if found, their number, size, and histology. Patients may be responsible for conveying results between primary and specialty care or providing medical information to family members; thus, accurate reporting is critical. This analysis assessed the accuracy of self-reported colonoscopy findings.

METHODS

3,986 participants from the Study of Colonoscopy Utilization, an ancillary study nested within the Prostate, Lung, Colorectal, and Ovarian Screening Trial, were included. Self-reports of polyp and adenoma were compared to medical records, and measures of sensitivity and specificity were calculated. Correlates of accurate self-report of polyp were assessed using logistic regression and weighted to account for study sampling.

RESULTS

The sensitivity and specificity of self-reported polyp findings were 88% and 85%, respectively, and for adenoma 11% and 99%, respectively. Among participants with a polyp, older age was associated with lower likelihood while polyp severity and non-white race were associated with increased likelihood of accurate recall. Among participants without a polyp, having multiple colonoscopies was associated with lower likelihood while family history of colorectal cancer was associated with increased likelihood of accurate recall. Among both groups, longer time since colonoscopy was associated with lower likelihood of accurate recall.

CONCLUSIONS

Participants recalled with reasonable accuracy whether they had a prior polyp; however, recall of histology, specifically adenoma, was much less accurate.

IMPACT

Identification of strategies to increase accurate self-report of colonic polyps are needed, particularly for patient-provider communications and patient reporting of results to family members.

Evaluating Lung Cancer Screening Across Diverse Healthcare Systems: A Process Model from the Lung PROSPR Consortium

Numerous organizations, including the United States Preventive Services Task Force, recommend annual lung cancer screening (LCS) with low-dose CT for high risk adults who meet specific criteria. Despite recommendations and national coverage for screening eligible adults through the Centers for Medicare and Medicaid Services, LCS uptake in the United States remains low (<4%). In recognition of the need to improve and understand LCS across the population, as part of the larger Population-based Research to Optimize the Screening PRocess (PROSPR) consortium, the NCI (Bethesda, MD) funded the Lung PROSPR Research Consortium consisting of five diverse healthcare systems in Colorado, Hawaii, Michigan, Pennsylvania, and Wisconsin. Using various methods and data sources, the center aims to examine utilization and outcomes of LCS across diverse populations, and assess how variations in the implementation of LCS programs shape outcomes across the screening process. This commentary presents the PROSPR LCS process model, which outlines the interrelated steps needed to complete the screening process from risk assessment to treatment. In addition to guiding planned projects within the Lung PROSPR Research Consortium, this model provides insights on the complex steps needed to implement, evaluate, and improve LCS outcomes in community practice.

Screening colonoscopy and flexible sigmoidoscopy for reduction of colorectal cancer incidence: A case-control study

BACKGROUND

Flexible sigmoidoscopy and colonoscopy are both recommended colorectal cancer screening options, but their relative effectiveness needs clarification. The aim of this study was to compare the effectiveness of colonoscopy and flexible sigmoidoscopy for reduction of colorectal cancer incidence.

METHODS

We conducted a case-control study within the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Cases were subjects age 70-85 years in the SEER-Medicare database diagnosed with CRC during 2004-2013. Up to 3 controls were matched to each case by birth year, sex, race, and SEER region. Receipt of screening colonoscopy or flexible sigmoidoscopy was ascertained from Medicare claims. Conditional logistic regression models were developed to estimate the odds ratios (ORs) and 95% confidence intervals (CI) for a history of screening in cases vs. controls. We conducted secondary analyses by sex, race, endoscopist characteristics, and with varying timing and duration of the look-back period.

RESULTS

Receipt of screening colonoscopy and sigmoidoscopy was associated with a 59% (OR 0.41, 95%CI 0.39, 0.43) and 22% reduction (OR 0.78, 95%CI 0.67, 0.92) in colorectal cancer incidence, respectively. Colonoscopy was associated with greater reduction in the distal colorectal cancer incidence (OR 0.22, 95%CI 0.20, 0.24) than proximal colorectal cancer incidence (OR 0.62, 95%CI 0.59, 0.66). Sigmoidoscopy was associated with a 52% reduction in distal colorectal cancer incidence (OR 0.48, 95%CI 0.37, 0.63), but with no reduction in proximal colorectal cancer incidence. These associations were stronger in men than in women. No differences by race or endoscopist characteristics were observed.

CONCLUSION

Both screening colonoscopy and sigmoidoscopy were associated with reductions in overall colorectal cancer incidence, with a greater magnitude of reduction observed with colonoscopy.

Colonoscopy Indication Algorithm Performance Across Diverse Health Care Systems in the PROSPR Consortium

BACKGROUND

Despite the importance of characterizing colonoscopy indication for quality monitoring and cancer screening program evaluation, there is no standard approach to documenting colonoscopy indication in medical records.

METHODS

We applied two algorithms in three health care systems to assign colonoscopy indication to persons 50-89 years old who received a colonoscopy during 2010-2013. Both algorithms used standard procedure, diagnostic, and laboratory codes. One algorithm, the KPNC algorithm, used a hierarchical approach to classify exam indication into: diagnostic, surveillance, or screening; whereas the other, the SEARCH algorithm, used a logistic regression-based algorithm to provide the probability that colonoscopy was performed for screening. Gold standard assessment of indication was from medical records abstraction.

RESULTS

There were 1,796 colonoscopy exams included in analyses; age and racial/ethnic distributions of participants differed across health care systems. The KPNC algorithm's sensitivities and specificities for screening indication ranged from 0.78-0.82 and 0.78-0.91, respectively; sensitivities and specificities for diagnostic indication ranged from 0.78-0.89 and 0.74-0.82, respectively. The KPNC algorithm had poor sensitivities (ranging from 0.11-0.67) and high specificities for surveillance exams. The Area Under the Curve (AUC) of the SEARCH algorithm for screening indication ranged from 0.76-0.84 across health care systems. For screening indication, the KPNC algorithm obtained higher specificities than the SEARCH algorithm at the same sensitivity.

CONCLUSION

Despite standardized implementation of these indication algorithms across three health care systems, the capture of colonoscopy indication data was imperfect. Thus, we recommend that standard, systematic documentation of colonoscopy indication should be added to medical records to ensure efficient and accurate data capture.

Case-Control Studies of the Efficacy of Screening Tests That Seek to Prevent Cancer Incidence: Results of an Approach That Utilizes Administrative Claims Data That Do Not Provide Information Regarding Test Indication

Case-control studies evaluating a screening test's efficacy in reducing cancer mortality require accurate classification of test indication to obtain a valid result. However, for analogous studies of cancer incidence, determination of test indication is not as critical because, to define exposure, we need consider only tests that can identify precursor lesions whose treatment might prevent cancer, not tests leading to cancer diagnosis. This study utilizes US Surveillance, Epidemiology, and End Results (SEER)-Medicare data, which do not include information about colonoscopy indication, to evaluate the efficacy of colonoscopy in preventing colorectal cancer (CRC) incidence. Cases were Medicare enrollees diagnosed with CRC between 1996 and 2013; up to 3 controls were matched to each case. Colonoscopy receipt prior to presumed onset of occult cancer was associated with an approximately 60% reduction in CRC incidence (odds ratio = 0.41, 95% confidence interval: 0.40, 0.42). The association was robust to differing exposure windows and estimates of occult cancer duration and is similar to those from CRC incidence studies in which exam indication was available. Our results suggest that, when it is impractical/impossible to determine whether tests were conducted for screening, the efficacy of a test in preventing cancer incidence can still be estimated using a case-control study design.

Collaborating on Data, Science, and Infrastructure: The 20-Year Journey of the Cancer Research Network

The Cancer Research Network (CRN) is a consortium of 12 research groups, each affiliated with a nonprofit integrated health care delivery system, that was first funded in 1998. The overall goal of the CRN is to support and facilitate collaborative cancer research within its component delivery systems. This paper describes the CRN's 20-year experience and evolution. The network combined its members' scientific capabilities and data resources to create an infrastructure that has ultimately supported over 275 projects. Insights about the strengths and limitations of electronic health data for research, approaches to optimizing multidisciplinary collaboration, and the role of a health services research infrastructure to complement traditional clinical trials and large observational datasets are described, along with recommendations for other research consortia.

Lung Cancer Screening Inconsistent With U.S. Preventive Services Task Force Recommendations

INTRODUCTION

Prior studies suggest overuse of nonrecommended lung cancer screening tests in U.S. community practice and underuse of recommended tests.

METHODS

Data from the 2010 and 2015 National Health Interview Surveys was analyzed from 2016 to 2018. Prevalence, populations, and number of chest computed tomography (CT) and chest x-ray tests were estimated for people who did and did not meet U.S. Preventive Services Task Force (USPSTF) criteria for lung cancer screening, among people aged ≥40 years without lung cancer.

RESULTS

In 2015, among those who met USPSTF criteria, 4.4% (95% CI=3.0%, 6.6%), or 360,000 (95% CI=240,000, 535,000) people reported lung cancer screening with a chest CT; and 8.5% (95% CI=6.5%, 11.1%), or 689,000 (95% CI=526,000, 898,000) people reported a chest x ray. Among those who did not meet USPSTF criteria, 2.3% (95% CI=2.0%, 2.6%), or 3,259,000 (95% CI=2,850,000, 3,724,000) people reported a chest x ray; and 1.3% (95% CI=1.1%, 1.5%), or 1,806,000 (95% CI=1,495,000, 2,173,000) people reported a chest CT. The estimated population meeting USPSTF criteria for lung cancer screening in 2015 was 8,098,000 (95% CI=7,533,000, 8,702,000), which was smaller than the 9,620,000 people (95% CI=8,960,000, 10,325,000) in 2010.

CONCLUSIONS

The number of adults inappropriately screened for lung cancer greatly exceeds the number screened according to USPSTF recommendations, the prevalence of appropriate lung cancer screening is low, and the population meeting USPSTF criteria is shrinking. To realize the potential benefits of screening, better processes to appropriately triage eligible individuals to screening, plus screening with a USPSTF-recommended test, would be beneficial.

Cervical cancer screening research in the PROSPR I consortium: Rationale, methods and baseline findings from a US cohort

Little is known about the effect of evolving risk-based cervical cancer screening and management guidelines on United States (US) clinical practice and patient outcomes. We describe the National Cancer Institute's Population-based Research Optimizing Screening through Personalized Regimens (PROSPR I) consortium, methods and baseline findings from its cervical sites: Kaiser Permanente Washington, Kaiser Permanente Northern California, Kaiser Permanente Southern California, Parkland Health & Hospital System/University of Texas Southwestern (Parkland-UTSW) and New Mexico HPV Pap Registry housed by University of New Mexico (UNM-NMHPVPR). Across these diverse healthcare settings, we collected data on human papillomavirus (HPV) vaccinations, screening tests/results, diagnostic and treatment procedures/results and cancer diagnoses on nearly 4.7 million women aged 18-89 years from 2010 to 2014. We calculated baseline (2012 for UNM-NMHPVPR; 2010 for other sites) frequencies for sociodemographics, cervical cancer risk factors and key screening process measures for each site's cohort. Healthcare delivery settings, cervical cancer screening strategy, race/ethnicity and insurance status varied among sites. The proportion of women receiving a Pap test during the baseline year was similar across sites (26.1-36.1%). Most high-risk HPV tests were performed either reflexively or as cotests, and utilization pattern varied by site. Prevalence of colposcopy or biopsy was higher at Parkland-UTSW (3.6%) than other sites (1.3-1.4%). Incident cervical cancer was rare. HPV vaccination among age-eligible women not already immunized was modest across sites (0.1-7.2%). Cervical PROSPR I makes available high-quality, multilevel, longitudinal screening process data from a large and diverse cohort of women to evaluate and improve the effectiveness of US cervical cancer screening delivery.

Receipt of Colonoscopy Following Diagnosis of Advanced Adenomas: An Analysis within Integrated Healthcare Delivery Systems

BACKGROUND

To reduce colorectal cancer incidence and mortality, experts recommend surveillance colonoscopy 3 years after advanced adenoma removal. Little is known about adherence to that interval.

METHODS

We describe patterns of and factors associated with subsequent colonoscopy among persons with ≥3 adenomas and/or ≥1 adenoma with villous/tubulovillous histology in four U.S. integrated healthcare delivery systems. We report Kaplan-Meier estimators of the cumulative percentage of patients undergoing colonoscopy 6 months to 3.5 years after an index colonoscopy with high-risk findings. Combining data from three healthcare systems, we used multivariable logistic regression with inverse probability of censoring weights to estimate ORs and 95% confidence intervals (CI) for associations between patient characteristics and receipt of subsequent colonoscopy.

RESULTS

Among 6,909 persons with advanced adenomas, the percent receiving a subsequent colonoscopy 6 months to 3.5 years later ranged from 18.3% (95% CI: 11.7%-27.8%) to 59.5% (95% CI: 53.8%-65.2%) across healthcare systems. Differences remained significant in the multivariable model. Patients with ≥3 adenomas were more likely than those with 1 to 2 villous/tubulovillous adenomas to undergo subsequent colonoscopy. Subsequent colonoscopy was also more common for patients ages 60-74 and less common for patients ages 80 to 89 compared with those ages 50 to 54 years at their index colonoscopy. Sex, race/ethnicity, and comorbidity index score were generally not associated with subsequent colonoscopy receipt.

CONCLUSIONS

Colonoscopy within the recommended interval following advanced adenoma was underutilized and varied by healthcare system, age, and number of adenomas.

IMPACT

Strategies to improve adherence to surveillance colonoscopy following advanced adenomas are needed.

Colorectal cancer screening in the United States: Trends from 2008 to 2015 and variation by health insurance coverage

Regular colorectal cancer (CRC) screening is recommended for reducing CRC incidence and mortality. This paper provides an updated analysis of CRC screening in the United States (US) and examines CRC screening by several features of health insurance coverage. Recommendation-consistent CRC screening was calculated for adults aged 50-75 in 2008, 2010, 2013 and 2015 using data from the National Health Interview Survey. CRC screening prevalence in 2015 was described overall and by sociodemographic subgroups. CRC screening by health insurance coverage was further examined using multivariable logistic regression, stratified by age (50-64 years and 65-75 years) and adjusted for age, race/ethnicity, sex, education, income, time in US, and comorbid conditions. Recommendation-consistent screening increased from 51.6% in 2008 to 58.3% in 2010 (p < 0.001). Use plateaued from 2010 to 2013 but increased to 61.3% in 2015 (p < 0.001). In 2015, adults aged 50-64 years with traditional employer-sponsored private insurance were more likely to be screened (62.2%) than those with traditional private direct purchase plans (50.9%) and the uninsured (24.8%) (p < 0.01, respectively). After multivariable adjustment, differences between traditional employer-sponsored private insurance and the uninsured remained statistically significant. Adults aged 65-75 with Medicare and private insurance were more likely to be screened (76.3%) than those with Medicare, no supplemental insurance (68.8%) or Medicare and Medicaid (65.2%) (p < 0.001). After multivariable adjustment, the differences between Medicare and private insurance and Medicare no supplemental insurance remained statistically significant. CRC screening rates have increased over time, but certain segments of the population, especially the uninsured, continue to screen below recommended levels.

Effectiveness of screening colonoscopy in reducing the risk of death from right and left colon cancer: a large community-based study

OBJECTIVE

Screening colonoscopy's effectiveness in reducing colorectal cancer mortality risk in community populations is unclear, particularly for right-colon cancers, leading to recommendations against its use for screening in some countries. This study aimed to determine whether, among average-risk people, receipt of screening colonoscopy reduces the risk of dying from both right-colon and left-colon/rectal cancers.

DESIGN

We conducted a nested case-control study with incidence-density matching in screening-eligible Kaiser Permanente members. Patients who were 55-90 years old on their colorectal cancer death date during 2006-2012 were matched on diagnosis (reference) date to controls on age, sex, health plan enrolment duration and geographical region. We excluded patients at increased colorectal cancer risk, or with prior colorectal cancer diagnosis or colectomy. The association between screening colonoscopy receipt in the 10-year period before the reference date and colorectal cancer death risk was evaluated while accounting for other screening exposures.

RESULTS

We analysed 1747 patients who died from colorectal cancer and 3460 colorectal cancer-free controls. Compared with no endoscopic screening, receipt of a screening colonoscopy was associated with a 67% reduction in the risk of death from any colorectal cancer (adjusted OR (aOR)=0.33, 95% CI 0.21 to 0.52). By cancer location, screening colonoscopy was associated with a 65% reduction in risk of death for right-colon cancers (aOR=0.35, CI 0.18 to 0.65) and a 75% reduction for left-colon/rectal cancers (aOR=0.25, CI 0.12 to 0.53).

CONCLUSIONS

Screening colonoscopy was associated with a substantial and comparably decreased mortality risk for both right-sided and left-sided cancers within a large community-based population.

Training in the Conduct of Population-Based Multi-Site and Multi-Disciplinary Studies: the Cancer Research Network's Scholars Program

Expanding research capacity of large research networks within health care delivery systems requires strategically training both embedded and external investigators in necessary skills for this purpose. Researchers new to these settings frequently lack the skills and specialized knowledge conducive to multi-site and multi-disciplinary research set in delivery systems. This report describes the goals and components of the Cancer Research Network (CRN) Scholars Program, a 26-month training program developed to increase the capacity for cancer research conducted within the network's participating sites, its progression from training embedded investigators to a mix of internal and external investigators, and the content evolution of the training program. The CRN Scholars program was launched in 2007 to assist junior investigators from member sites develop independent and sustainable research programs within the CRN. Resulting from CRN's increased emphasis on promoting external collaborations, the 2013 Scholars program began recruiting junior investigators from external institutions committed to conducting delivery system science. Based on involvement of this broader population and feedback from prior Scholar cohorts, the program has honed its focus on specific opportunities and issues encountered in conducting cancer research within health care delivery systems. Efficiency and effectiveness of working within networks is accelerated by strategic and mentored navigation of these networks. Investing in training programs specific to these settings provides the opportunity to improve multi-disciplinary and multi-institutional collaboration, particularly for early-stage investigators. Aspects of the CRN Scholars Program may help inform others considering developing similar programs to expand delivery system research or within large, multi-disciplinary research networks.

Population-Based Precision Cancer Screening: A Symposium on Evidence, Epidemiology, and Next Steps

Precision medicine, an emerging approach for disease treatment that takes into account individual variability in genes, environment, and lifestyle, is under consideration for preventive interventions, including cancer screening. On September 29, 2015, the National Cancer Institute sponsored a symposium entitled "Precision Cancer Screening in the General Population: Evidence, Epidemiology, and Next Steps". The goal was two-fold: to share current information on the evidence, practices, and challenges surrounding precision screening for breast, cervical, colorectal, lung, and prostate cancers, and to allow for in-depth discussion among experts in relevant fields regarding how epidemiology and other population sciences can be used to generate evidence to inform precision screening strategies. Attendees concluded that the strength of evidence for efficacy and effectiveness of precision strategies varies by cancer site, that no one research strategy or methodology would be able or appropriate to address the many knowledge gaps in precision screening, and that issues surrounding implementation must be researched as well. Additional discussion needs to occur to identify the high priority research areas in precision cancer screening for pertinent organs and to gather the necessary evidence to determine whether further implementation of precision cancer screening strategies in the general population would be feasible and beneficial. Cancer Epidemiol Biomarkers Prev; 25(11); 1449-55. ©2016 AACR.

Validation of Models Used to Inform Colorectal Cancer Screening Guidelines: Accuracy and Implications

BACKGROUND

Microsimulation models synthesize evidence about disease processes and interventions, providing a method for predicting long-term benefits and harms of prevention, screening, and treatment strategies. Because models often require assumptions about unobservable processes, assessing a model's predictive accuracy is important.

METHODS

We validated 3 colorectal cancer (CRC) microsimulation models against outcomes from the United Kingdom Flexible Sigmoidoscopy Screening (UKFSS) Trial, a randomized controlled trial that examined the effectiveness of one-time flexible sigmoidoscopy screening to reduce CRC mortality. The models incorporate different assumptions about the time from adenoma initiation to development of preclinical and symptomatic CRC. Analyses compare model predictions to study estimates across a range of outcomes to provide insight into the accuracy of model assumptions.

RESULTS

All 3 models accurately predicted the relative reduction in CRC mortality 10 years after screening (predicted hazard ratios, with 95% percentile intervals: 0.56 [0.44, 0.71], 0.63 [0.51, 0.75], 0.68 [0.53, 0.83]; estimated with 95% confidence interval: 0.56 [0.45, 0.69]). Two models with longer average preclinical duration accurately predicted the relative reduction in 10-year CRC incidence. Two models with longer mean sojourn time accurately predicted the number of screen-detected cancers. All 3 models predicted too many proximal adenomas among patients referred to colonoscopy.

CONCLUSION

Model accuracy can only be established through external validation. Analyses such as these are therefore essential for any decision model. Results supported the assumptions that the average time from adenoma initiation to development of preclinical cancer is long (up to 25 years), and mean sojourn time is close to 4 years, suggesting the window for early detection and intervention by screening is relatively long. Variation in dwell time remains uncertain and could have important clinical and policy implications.

Estimation of Benefits, Burden, and Harms of Colorectal Cancer Screening Strategies: Modeling Study for the US Preventive Services Task Force

IMPORTANCE

The US Preventive Services Task Force (USPSTF) is updating its 2008 colorectal cancer (CRC) screening recommendations.

OBJECTIVE

To inform the USPSTF by modeling the benefits, burden, and harms of CRC screening strategies; estimating the optimal ages to begin and end screening; and identifying a set of model-recommendable strategies that provide similar life-years gained (LYG) and a comparable balance between LYG and screening burden.

DESIGN, SETTING, AND PARTICIPANTS

Comparative modeling with 3 microsimulation models of a hypothetical cohort of previously unscreened US 40-year-olds with no prior CRC diagnosis.

EXPOSURES

Screening with sensitive guaiac-based fecal occult blood testing, fecal immunochemical testing (FIT), multitarget stool DNA testing, flexible sigmoidoscopy with or without stool testing, computed tomographic colonography (CTC), or colonoscopy starting at age 45, 50, or 55 years and ending at age 75, 80, or 85 years. Screening intervals varied by modality. Full adherence for all strategies was assumed.

MAIN OUTCOMES AND MEASURES

Life-years gained compared with no screening (benefit), lifetime number of colonoscopies required (burden), lifetime number of colonoscopy complications (harms), and ratios of incremental burden and benefit (efficiency ratios) per 1000 40-year-olds.

RESULTS

The screening strategies provided LYG in the range of 152 to 313 per 1000 40-year-olds. Lifetime colonoscopy burden per 1000 persons ranged from fewer than 900 (FIT every 3 years from ages 55-75 years) to more than 7500 (colonoscopy screening every 5 years from ages 45-85 years). Harm from screening was at most 23 complications per 1000 persons screened. Strategies with screening beginning at age 50 years generally provided more LYG as well as more additional LYG per additional colonoscopy than strategies with screening beginning at age 55 years. There were limited empirical data to support a start age of 45 years. For persons adequately screened up to age 75 years, additional screening yielded small increases in LYG relative to the increase in colonoscopy burden. With screening from ages 50 to 75 years, 4 strategies yielded a comparable balance of screening burden and similar LYG (median LYG per 1000 across the models): colonoscopy every 10 years (270 LYG); sigmoidoscopy every 10 years with annual FIT (256 LYG); CTC every 5 years (248 LYG); and annual FIT (244 LYG).

CONCLUSIONS AND RELEVANCE

In this microsimulation modeling study of a previously unscreened population undergoing CRC screening that assumed 100% adherence, the strategies of colonoscopy every 10 years, annual FIT, sigmoidoscopy every 10 years with annual FIT, and CTC every 5 years performed from ages 50 through 75 years provided similar LYG and a comparable balance of benefit and screening burden.

Ten-year incidence of colorectal cancer following a negative screening sigmoidoscopy: an update from the Colorectal Cancer Prevention (CoCaP) programme

OBJECTIVE

To examine the rates of colorectal cancer (CRC) following a negative screening sigmoidoscopy.

DESIGN

Cohort study.

SETTING

An integrated healthcare delivery organisation in California, USA.

PARTICIPANTS

72,483 men and women aged 50 years and above who had a negative screening sigmoidoscopy between 1994 and 1996. Those at elevated risk of CRC due to inflammatory bowel disease, prior polyps or CRC, or a strong family history of CRC were excluded.

MAIN OUTCOME MEASURES

Incidence rates of distal and proximal CRC. Standardised Incidence Ratios were used to compare annual incidence rates of distal and proximal CRC in the cohort to expected rates based on Surveillance, Epidemiology, and End Results data. Additionally, rate ratios (RR) and rate differences (RD) comparing the incidence rate of distal CRC in years 6+ postscreening with that in years 1-5 were calculated.

RESULTS

Incidence rates of distal CRC were lower than those in the San Francisco Bay area population at large during each of the first 10 years postsigmoidoscopy screening. However, the incidence of distal CRC rose steadily, from 3 per 100,000 in the first year of follow-up to 40 per 100,000 in the 10th year. During the second half of follow-up, the rate of distal CRC was twice as high as in the first half (RR 2 .08, 95% CI 1.38 to 3.16; RD 14 per 100,000 person-years, 95% CI 6 to 22).

CONCLUSIONS

Though still below population levels, the incidence of CRC during years 6-10 following a negative sigmoiodoscopy is appreciably higher than during the first 5 years.

Occurrence of Distal Colorectal Neoplasia Among Whites and Blacks Following Negative Flexible Sigmoidoscopy: An Analysis of PLCO Trial

BACKGROUND

It is unclear whether the higher rate of colorectal cancer (CRC) among non-Hispanic blacks (blacks) is due to lower rates of CRC screening or greater biologic risk.

OBJECTIVE

We aimed to evaluate whether blacks are more likely than non-Hispanic whites (whites) to develop distal colon neoplasia (adenoma and/or cancer) after negative flexible sigmoidoscopy (FSG).

DESIGN

We analyzed data of participants with negative FSGs at baseline in the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial who underwent repeat FSGs 3 or 5 years later. Subjects with polyps or masses were referred to their physicians for diagnostic colonoscopy. We collected and reviewed the records of diagnostic evaluations.

PARTICIPANTS

Our analytic cohort consisted of 21,550 whites and 975 blacks.

MAIN MEASURES

We did a comparison by race (whites vs. blacks) in the findings of polyps or masses at repeat FSG, the follow-up of abnormal test results and the detection of colorectal neoplasia at diagnostic colonoscopy.

KEY RESULTS

At the follow-up FSG examination, 304 blacks (31.2 %) and 4183 whites (19.4 %) had abnormal FSG, [adjusted relative risk (RR) = 1.00; 95 % confidence interval (CI), 0.90-1.10]. However, blacks were less likely to undergo diagnostic colonoscopy (76.6 % vs. 83.1 %; RR = 0.90; 95 % CI, 0.84-0.96). Among all included patients, blacks had similar risk of any distal adenoma (RR = 0.86; 95 % CI, 0.65-1.14) and distal advanced adenoma (RR = 1.01; 95 % CI, 0.60-1.68). Similar results were obtained when we restricted our analysis to compliant subjects who underwent diagnostic colonoscopy (RR = 1.01; 95 % CI, 0.80-1.29) for any distal adenoma and (RR = 1.18; 95 % CI, 0.73-1.92) for distal advanced adenoma.

CONCLUSIONS

We did not find any differences between blacks and whites in the risk of distal colorectal adenoma 3-5 years after negative FSG. However, follow-up evaluations were lower among blacks.

Observational methods to assess the effectiveness of screening colonoscopy in reducing right colon cancer mortality risk: SCOLAR

AIMS

Screening colonoscopy's effectiveness in reducing risk of death from right colon cancers remains unclear. Methodological challenges of existing observational studies addressing this issue motivated the design of 'Effectiveness of Screening for Colorectal Cancer in Average-Risk Adults (SCOLAR)'.

METHODS

SCOLAR is a nested case-control study based on two large integrated health systems. This affords access to a large, well-defined historical cohort linked to integrated data on cancer outcomes, patient eligibility, test indications and important confounders.

RESULTS

We found electronic data adequate for excluding ineligible patients (except family history), but not the detailed information needed for test indication assignment.

CONCLUSION

The lessons of SCOLAR's design and implementation may be useful for future studies seeking to evaluate the effectiveness of screening tests in community settings.

Development of an Algorithm to Classify Colonoscopy Indication from Coded Health Care Data

Introduction:

Electronic health data are potentially valuable resources for evaluating colonoscopy screening utilization and effectiveness. The ability to distinguish screening colonoscopies from exams performed for other purposes is critical for research that examines factors related to screening uptake and adherence, and the impact of screening on patient outcomes, but distinguishing between these indications in secondary health data proves challenging. The objective of this study is to develop a new and more accurate algorithm for identification of screening colonoscopies using electronic health data.

Methods:

Data from a case-control study of colorectal cancer with adjudicated colonoscopy indication was used to develop logistic regression-based algorithms. The proposed algorithms predict the probability that a colonoscopy was indicated for screening, with variables selected for inclusion in the models using the Least Absolute Shrinkage and Selection Operator (LASSO).

Results:

The algorithms had excellent classification accuracy in internal validation. The primary, restricted model had AUC= 0.94, sensitivity=0.91, and specificity=0.82. The secondary, extended model had AUC=0.96, sensitivity=0.88, and specificity=0.90.

Discussion:

The LASSO approach enabled estimation of parsimonious algorithms that identified screening colonoscopies with high accuracy in our study population. External validation is needed to replicate these results and to explore the performance of these algorithms in other settings.

Leveraging biospecimen resources for discovery or validation of markers for early cancer detection

Validation of early detection cancer biomarkers has proven to be disappointing when initial promising claims have often not been reproducible in diagnostic samples or did not extend to prediagnostic samples. The previously reported lack of rigorous internal validity (systematic differences between compared groups) and external validity (lack of generalizability beyond compared groups) may be effectively addressed by utilizing blood specimens and data collected within well-conducted cohort studies. Cohort studies with prediagnostic specimens (eg, blood specimens collected prior to development of clinical symptoms) and clinical data have recently been used to assess the validity of some early detection biomarkers. With this background, the Division of Cancer Control and Population Sciences (DCCPS) and the Division of Cancer Prevention (DCP) of the National Cancer Institute (NCI) held a joint workshop in August 2013. The goal was to advance early detection cancer research by considering how the infrastructure of cohort studies that already exist or are being developed might be leveraged to include appropriate blood specimens, including prediagnostic specimens, ideally collected at periodic intervals, along with clinical data about symptom status and cancer diagnosis. Three overarching recommendations emerged from the discussions: 1) facilitate sharing of existing specimens and data, 2) encourage collaboration among scientists developing biomarkers and those conducting observational cohort studies or managing healthcare systems with cohorts followed over time, and 3) conduct pilot projects that identify and address key logistic and feasibility issues regarding how appropriate specimens and clinical data might be collected at reasonable effort and cost within existing or future cohorts.

Vital signs: cervical cancer incidence, mortality, and screening - United States, 2007-2012

BACKGROUND

Cervical cancer screening is one of the greatest cancer prevention achievements, yet some women still develop or die from this disease.

OBJECTIVE

To assess recent trends in cervical cancer incidence and mortality, current screening percentages, and factors associated with higher incidence and death rates and inadequate screening.

METHODS

Percentages of women who had not been screened for cervical cancer in the past 5 years were estimated using data from the 2012 Behavioral Risk Factor Surveillance System survey. State-specific cervical cancer incidence data from the United States Cancer Statistics and mortality data from the National Vital Statistics System were used to calculate incidence and death rates for 2011 by state. Incidence and death rates and annual percentage changes from 2007 to 2011 were calculated by state and U.S. Census region.

RESULTS

In 2012, the percentage of women who had not been screened for cervical cancer in the past 5 years was estimated to be 11.4%; the percentage was larger for women without health insurance (23.1%) and for those without a regular health care provider (25.5%). From 2007 to 2011, the cervical cancer incidence rate decreased by 1.9% per year while the death rate remained stable. The South had the highest incidence rate (8.5 per 100,000), death rate (2.7 per 100,000), and percentage of women who had not been screened in the past 5 years (12.3%).

CONCLUSIONS

Trends in cervical cancer incidence rates have decreased slightly while death rates have been stable over the last 5 years. The proportion of inadequately screened women is higher among older women, Asians/Pacific Islanders, and American Indians/Alaska Natives.

IMPLICATIONS FOR PUBLIC HEALTH PRACTICE

There continue to be women who are not screened as recommended, and women who die from this preventable cancer. Evidence-based public health approaches are available to increase women's access to screening and timely follow-up of abnormal results.

Treatment of de novo acute myeloid leukemia in the United States: a report from the Patterns of Care program

Few US studies have examined patterns of care (POC) for acute myeloid leukemia (AML) in community settings. We examined treatment and survival in 978 adults with AML sampled from Surveillance, Epidemiology, and End Results (SEER) registries through the POC program. Logistic regression was used to evaluate the association between patient/hospital characteristics and receipt of chemotherapy and allogeneic transplant. Survival was examined using proportional hazards models. Treatment with cytarabine/anthracycline occurred in > 80% of patients without acute promeyelocytic leukemia (non-APL) < 60, but only about one-third of older non-APL patients. Ultimately, 27% of those < 60 received an allogeneic transplant. Thirty-seven percent of those < 40 and 4% of those ≥ 80 were alive at the end of follow-up. About three-quarters of patients with APL received all-trans retinoic acid (ATRA) and either an anthracycline or arsenic trioxide, with 71% surviving. Age and APL diagnosis were the strongest predictors of treatment and survival. Trends in dissemination of novel diagnostic tests and treatments and in survival will be monitored by POC in future years.

Approaches for classifying the indications for colonoscopy using detailed clinical data

Background

Accurate indication classification is critical for obtaining unbiased estimates of colonoscopy effectiveness and quality improvement efforts, but there is a dearth of published systematic classification approaches. The objective of this study was to evaluate the effects of data-source and adjudication on indication classification and on estimates of the effectiveness of screening colonoscopy on late-stage colorectal cancer diagnosis risk.

Methods

This was an observational study in members of four U.S. health plans. Eligible persons (n = 1039) were age 55–85 and had been enrolled for 5 years or longer in their health plans during 2006–2008. Patients were selected based on late-stage colorectal cancer diagnosis in a case–control design; each case patient was matched to 1–2 controls by study site, age, sex, and health plan enrollment duration. Reasons for colonoscopies received in the 10-year period before the reference date were collected from three medical records sources (progress notes; referral notes; procedure reports) and categorized using an algorithm, with committee adjudication of some tests. We evaluated indication classification concordance before and after adjudication and used logistic regressions with the Wald Chi-square test to compare estimates of the effects of screening colonoscopy on late-stage colorectal cancer diagnosis risk for each of our data sources to the adjudicated indication.

Results

Classification agreement between each data-source and adjudication was 78.8-94.0% (weighted kappa = 0.53-0.72); the highest agreement (weighted kappa = 0.86-0.88) was when information from all data sources was considered together. The choice of data-source influenced the association between screening colonoscopy and late-stage colorectal cancer diagnosis; estimates based on progress notes were closest to those based on the adjudicated indication (% difference in regression coefficients = 2.4%, p-value = 0.98), as compared to estimates from only referral notes (% difference in coefficients = 34.9%, p-value = 0.12) or procedure reports (% difference in coefficients = 27.4%, p-value = 0.23).

Conclusion

There was no single gold-standard source of information in medical records. The estimates of colonoscopy effectiveness from progress notes alone were the closest to estimates using adjudicated indications. Thus, the details in the medical records are necessary for accurate indication classification.

Uncontrolled confounding in studies of screening effectiveness: an example of colonoscopy

OBJECTIVE

To estimate the expected magnitude of error produced by uncontrolled confounding from health behaviours in observational medical record-based studies evaluating effectiveness of screening colonoscopy.

METHODS

We used data from the prospective National Institutes of Health American Association of Retired Persons (NIH-AARP) Diet and Health Study to assess the impact of health behaviour related factors (lifestyle, education, and use of non-steroidal anti-inflammatory drugs [NSAID]) on the association between colonoscopy and colorectal cancer (CRC) mortality. We first examined the difference between adjusted and unadjusted results within the cohort data, and then estimated a broader range of likely confounding errors based on the Breslow-Day approach that uses prevalence of confounders among persons with and without exposure, and the rate ratio reflecting the association between these confounders and the outcome of interest. As dietary factors and habits are often inter-correlated, we combined these variables (physical activity, body mass index, waist-to-hip ratio, alcohol consumption, and intakes of red meat, processed meat, fibre, milk, and calcium) into a "healthy lifestyle score" (HLS).

RESULTS

The estimated error (a ratio of biased-to-true result) attributable to confounding by HLS was 0.959-0.997, indicating less than 5% departure from the true effect of colonoscopy on CRC mortality. The corresponding errors ranged from 0.970 to 0.996 for NSAID, and from 0.974 to 1.006 for education (all ≤3% difference). The results for other CRC screening tests were similar.

CONCLUSION

Health behaviour-related confounders, either alone or in combination, seem unlikely to strongly affect the association between colonoscopy and CRC mortality in observational studies of CRC screening.

Measurement in comparative effectiveness research

Comparative effectiveness research (CER) on preventive services can shape policy and help patients, their providers, and public health practitioners select regimens and programs for disease prevention. Patients and providers need information about the relative effectiveness of various regimens they may choose. Decision makers need information about the relative effectiveness of various programs to offer or recommend. The goal of this paper is to define and differentiate measures of relative effectiveness of regimens and programs for disease prevention. Cancer screening is used to demonstrate how these measures differ in an example of two hypothetical screening regimens and programs. Conceptually and algebraically defined measures of relative regimen and program effectiveness also are presented. The measures evaluate preventive services that range from individual tests through organized, population-wide prevention programs. Examples illustrate how effective screening regimens may not result in effective screening programs and how measures can vary across subgroups and settings. Both regimen and program relative effectiveness measures assess benefits of prevention services in real-world settings, but each addresses different scientific and policy questions. As the body of CER grows, a common lexicon for various measures of relative effectiveness becomes increasingly important to facilitate communication and shared understanding among researchers, healthcare providers, patients, and policymakers.

Screening colonoscopy and risk for incident late-stage colorectal cancer diagnosis in average-risk adults: a nested case-control study

BACKGROUND

The effectiveness of screening colonoscopy in average-risk adults is uncertain, particularly for right colon cancer.

OBJECTIVE

To examine the association between screening colonoscopy and risk for incident late-stage colorectal cancer (CRC).

DESIGN

Nested case-control study.

SETTING

Four U.S. health plans.

PATIENTS

1039 average-risk adults enrolled for at least 5 years in one of the health plans. Case patients were aged 55 to 85 years on their diagnosis date (reference date) of stage IIB or higher (late-stage) CRC during 2006 to 2008. One or 2 control patients were selected for each case patient, matched on birth year, sex, health plan, and prior enrollment duration.

MEASUREMENTS

Receipt of CRC screening 3 months to 10 years before the reference date, ascertained through medical record audits. Case patients and control patients were compared on receipt of screening colonoscopy or sigmoidoscopy by using conditional logistic regression that accounted for health history, socioeconomic status, and other screening exposures.

RESULTS

In analyses restricted to 471 eligible case patients and their 509 matched control patients, 13 case patients (2.8%) and 46 control patients (9.0%) had undergone screening colonoscopy, which corresponded to an adjusted odds ratio (AOR) of 0.29 (95% CI, 0.15 to 0.58) for any late-stage CRC, 0.36 (CI, 0.16 to 0.80) for right colon cancer, and 0.26 (CI, 0.06 to 1.11; P = 0.069) for left colon/rectum cancer. Ninety-two case patients (19.5%) and 173 control patients (34.0%) had screening sigmoidoscopy, corresponding to an AOR of 0.50 (CI, 0.36 to 0.70) overall, 0.79 (CI, 0.51 to 1.23) for right colon late-stage cancer, and 0.26 (CI, 0.14 to 0.48) for left colon cancer.

LIMITATION

The small number of screening colonoscopies affected the precision of the estimates.

CONCLUSION

Screening with colonoscopy in average-risk persons was associated with reduced risk for diagnosis of incident late-stage CRC, including right-sided colon cancer. For sigmoidoscopy, this association was seen for left CRC, but the association for right colon late-stage cancer was not statistically significant.

Factors associated with the risk of adenoma recurrence in distal and proximal colon

BACKGROUND/AIMS

Colonoscopy may be less effective in preventing cancer in the proximal colon. We evaluated whether risk factors for adenoma recurrence exhibit differential effect on adenoma recurrence by colon subsite.

METHODS

We examined the association of age, sex, body mass index, smoking status and use of nonsteroidal anti-inflammatory drugs (NSAIDs) on proximal and distal adenoma recurrence among 1,864 participants in the Polyp Prevention Trial. We used multinomial logistic regression models to calculate the relative risk ratios (RRR) and 95% CI.

RESULTS

733 (39.3%) participants had adenoma recurrence (228 distal only, 369 proximal only and 136 synchronous proximal and distal adenoma). When compared to participants without adenoma recurrence, no factor was associated with an increased risk of distal only adenoma recurrence. Age 65-69 years (RRR = 1.47, 95% CI 1.00-2.16), age ≥70 years (RRR = 2.24, 95% CI 1.57-3.20), and male sex (RRR = 1.73, 95% CI 1.32-2.27) were positively associated with proximal only adenoma recurrence. NSAIDs use was associated with a reduced risk of adenoma recurrence by similar magnitude in distal (RRR = 0.78, 95% CI 0.58-1.07) and proximal colon (RRR = 0.77, 95% CI 0.60-1.00).

CONCLUSIONS

We did not find any modifiable risk factor that differentially increases proximal as compared to distal adenoma recurrence to be clinically useful for targeted intervention.

Use of lung cancer screening tests in the United States: results from the 2010 National Health Interview Survey

BACKGROUND

Before evidence of efficacy, lung cancer screening was being ordered by many physicians. The National Lung Screening Trial (NLST), which showed a 20% reduction in lung cancer mortality among those randomized to receive low-dose computed tomography (LDCT), will likely lead to increased screening use.

METHODS

We estimated the prevalence of chest X-ray and CT use in the United States using data from the 2010 National Health Interview Survey (NHIS). Subjects included 15,537 NHIS respondents aged ≥40 years without prior diagnosis of lung cancer. Estimates of the size of the U. S. population by age and smoking status were calculated. Multivariate logistic regression examined predictors of test use adjusting for potential confounders.

RESULTS

Twenty-three percent of adults reported chest X-ray in the previous year and 2.5% reported chest X-ray specifically to check for lung cancer; corresponding numbers for chest CT were 7.5% and 1.3%. Older age, black race, male gender, smoking, respiratory disease, personal history of cancer, and having health insurance were associated with test use. Approximately, 8.7 million adults in the United States would be eligible for LDCT screening according to NLST eligibility criteria.

CONCLUSIONS AND IMPACT

Monitoring of trends in the use of lung screening tests will be vital to assess the impact of NLST and possible changes in lung cancer screening recommendations and insurance coverage in the future. Education of patients by their physicians, and of the general public, may help ensure that screening is used appropriately, in those most likely to benefit.

Association between colonoscopy and colorectal cancer mortality in a US cohort according to site of cancer and colonoscopist specialty

PURPOSE

We designed this study to evaluate the association of colonoscopy with colorectal cancer (CRC) death in the United States by site of CRC and endoscopist specialty.

METHODS

We designed a case-control study using Surveillance, Epidemiology, and End Results (SEER)-Medicare data. We identified patients (cases) diagnosed with CRC age 70 to 89 years from January 1998 through December 2002 who died as a result of CRC by 2007. We selected three matched controls without cancer for each case. Controls were assigned a referent date (date of diagnosis of the case). Colonoscopy performed from January 1991 through 6 months before the diagnosis/referent date was our primary exposure. We compared exposure to colonoscopy in cases and controls by using conditional logistic regression controlling for covariates, stratified by site of CRC. We determined endoscopist specialty by linkage to the American Medical Association (AMA) Masterfile. We assessed whether the association between colonoscopy and CRC death varied with endoscopist specialty.

RESULTS

We identified 9,458 cases (3,963 proximal [41.9%], 4,685 distal [49.5%], and 810 unknown site [8.6%]) and 27,641 controls. In all, 11.3% of cases and 23.7% of controls underwent colonoscopy more than 6 months before diagnosis. Compared with controls, cases were less likely to have undergone colonoscopy (odds ratio [OR], 0.40; 95% CI, 0.37 to 0.43); the association was stronger for distal (OR, 0.24; 95% CI, 0.21 to 0.27) than proximal (OR, 0.58; 95% CI, 0.53 to 0.64) CRC. The strength of the association varied with endoscopist specialty.

CONCLUSION

Colonoscopy is associated with a reduced risk of death from CRC, with the association considerably and consistently stronger for distal versus proximal CRC. The overall association was strongest if colonoscopy was performed by a gastroenterologist.