Up-to-Date Breast, Cervical, and Colorectal Cancer Screening Test Use in the United States, 2021

INTRODUCTION

We examined national estimates of breast, cervical, and colorectal cancer (CRC) screening test use and compared them with Healthy People 2030 national targets. Test use in 2021 was compared with prepandemic estimates.

METHODS

In 2022, we used 2021 National Health Interview Survey (NHIS) data to estimate proportions of adults up to date with US Preventive Services Task Force recommendations for breast (women aged 50-74 y), cervical (women aged 21-65 y), and CRC screening (adults aged 50-75 y) across sociodemographic and health care access variables. We compared age-standardized estimates from the 2021 and 2019 NHIS.

RESULTS

Percentages of adults up to date in 2021 were 75.7% (95% CI, 74.4%-76.9%), 75.2% (95% CI, 73.9%-76.4%), and 72.2% (95% CI, 71.2%-73.2%) for breast, cervical, and CRC screening, respectively. Estimates were below 50% among those without a wellness check in 3 years (all screening types), among those without a usual source of care or insurance (aged <65 y) (breast and CRC screening), and among those residing in the US for less than 10 years (CRC screening). Percentages of adults who were up to date with breast and cervical cancer screening and colonoscopy were similar in 2019 and 2021. Fecal occult blood/fecal immunochemical test (FOBT/FIT) use was modestly higher in 2021 (P < .001).

CONCLUSIONS

In 2021, approximately 1 in 4 adults of screening age were not up to date with breast, cervical, and CRC screening recommendations, and Healthy People 2030 national targets were not met. Disparities existed across several characteristics, particularly those related to health care access. Breast, cervical, and colonoscopy test use within recommended screening intervals approximated prepandemic levels. FOBT/FIT estimates were modestly higher in 2021.

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.

Percentage Up to Date With Chest Computed Tomography Among Those Eligible for Lung Cancer Screening

INTRODUCTION

Authors aimed to calculate the percentage up-to-date with testing in the context of lung cancer screening across 5 healthcare systems and evaluate differences according to patient and health system characteristics.

METHODS

Lung cancer screening‒eligible individuals receiving care within the 5 systems in the Population-based Research to Optimize the Screening Process Lung consortium from October 1, 2018 to September 30, 2019 were included in analyses. Data collection was completed on June 15, 2021; final analyses were completed on April 1, 2022. Chest computed tomography scans and patient characteristics were obtained through electronic health records and used to calculate the percentage completing a chest computed tomography scan in the previous 12 months (considered up-to-date). The association of patient and healthcare system factors with being up-to-date was evaluated with adjusted prevalence ratios and 95% CIs using log-binomial regression models.

RESULTS

There were 29,417 individuals eligible for lung cancer screening as of September 30, 2019; 8,333 (28.3%) were up-to-date with testing. Those aged 65-74 years (prevalence ratio=1.19; CI=1.15, 1.24, versus ages 55-64), those with chronic obstructive pulmonary disease (prevalence ratio=2.05; CI=1.98, 2.13), and those in higher SES census tracts (prevalence ratio=1.22; CI=1.16, 1.30, highest quintile versus lowest) were more likely to be up-to-date. Currently smoking (prevalence ratio=0.91; CI=0.88, 0.95), having a BMI ≥30 kg/m² (prevalence ratio=0.83; CI=0.77, 0.88), identifying as Native Hawaiian or other Pacific Islander (prevalence ratio=0.79; CI=0.68, 0.92), and having a decentralized lung cancer screening program (prevalence ratio=0.77; CI=0.74, 0.80) were inversely associated with being up-to-date.

CONCLUSIONS

The percentage up-to-date with testing among those eligible for lung cancer screening is well below up-to-date estimates for other types of cancer screening, and disparities in lung cancer screening participation remain.

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.

Racial Disparities in Adherence to Annual Lung Cancer Screening and Recommended Follow-Up Care: A Multicenter Cohort Study

Rationale: Black patients receive recommended lung cancer screening (LCS) follow-up care less frequently than White patients, but it is unknown if this racial disparity persists across both decentralized and centralized LCS programs. Objectives: To determine adherence to American College of Radiology Lung Imaging Reporting and Data System (Lung-RADS) recommendations among individuals undergoing LCS at either decentralized or centralized programs and to evaluate the association of race with LCS adherence. Methods: We performed a multicenter retrospective cohort study of patients receiving LCS at five heterogeneous U.S. healthcare systems. We calculated adherence to annual LCS among patients with a negative baseline screen (Lung-RADS 1 or 2) and recommended follow-up care among those with a positive baseline screen (Lung-RADS 3, 4A, 4B, or 4X) stratified by type of LCS program and evaluated the association between race and adherence using multivariable modified Poisson regression. Results: Of the 6,134 total individuals receiving LCS, 5,142 (83.8%) had negative baseline screens, and 992 (16.2%) had positive baseline screens. Adherence to both annual LCS (34.8% vs. 76.1%; P < 0.001) and recommended follow-up care (63.9% vs. 74.6%; P < 0.001) was lower at decentralized compared with centralized programs. Among individuals with negative baseline screens, a racial disparity in adherence was observed only at decentralized screening programs (interaction term, P < 0.001). At decentralized programs, Black race was associated with 27% reduced adherence to annual LCS (adjusted relative risk [aRR], 0.73; 95% confidence interval [CI], 0.63-0.84), whereas at centralized programs, no effect by race was observed (aRR, 0.98; 95% CI, 0.91-1.05). In contrast, among those with positive baseline screens, there was no significant difference by race for adherence to recommended follow-up care by type of LCS program (decentralized aRR, 0.95; 95% CI, 0.81-1.11; centralized aRR, 0.81; 95% CI, 0.71-0.93; interaction term, P = 0.176). Conclusions: In this large multicenter study of individuals screened for lung cancer, adherence to both annual LCS and recommended follow-up care was greater at centralized screening programs. Black patients were less likely to receive annual LCS than White patients at decentralized compared with centralized LCS programs. Our results highlight the need for further study of healthcare system-level mechanisms to optimize longitudinal LCS care.

Cancer Screening Test Use-U.S., 2019

INTRODUCTION

The U.S. Preventive Services Task Force recommends breast, cervical, and colorectal cancer screening to reduce mortality from these cancers, but screening use has been below national targets. The purpose of this study is to examine the proportion of screening-eligible adults who are up to date with these screenings and how screening use compares with Healthy People 2020 targets.

METHODS

Data from the 2019 National Health Interview Survey were used to examine the percentages of adults up to date with breast cancer screening among women aged 50‒74 years without previous breast cancer, cervical cancer screening among women aged 21‒65 years without previous cervical cancer or hysterectomy, and colorectal cancer screening among adults aged 50‒75 years without previous colorectal cancer. Estimates are presented by sociodemographic characteristics and healthcare access factors. Analyses were conducted in 2021.

RESULTS

Percentages of adults up to date were 76.2% (95% CI= 75.0, 77.5) for breast cancer screening, 76.4% (95% CI= 75.2, 77.6) for cervical cancer screening, and 68.3% (95% CI= 67.3, 69.3) for colorectal cancer screening. Although some population subgroups met breast and colorectal cancer screening targets (81.1% and 70.5%, respectively), many did not, and cervical cancer screening was below the target for all examined subgroups. Lower education and income, nonmetropolitan county of residence (which included rural counties), no usual source of care or health insurance coverage, and Medicaid coverage were associated with lower screening test use.

CONCLUSIONS

Estimated use of breast, cervical, and colorectal cancer screening tests based on the 2019 National Health Interview Survey were below national targets. Continued monitoring may allow for examination of screening trends, inform interventions, and track progress in eliminating disparities.

Estimating Cancer Screening Sensitivity and Specificity Using Healthcare Utilization Data: Defining the Accuracy Assessment Interval

The effectiveness and efficiency of cancer screening in real-world settings depend on many factors, including test sensitivity and specificity. Outside of select experimental studies, not everyone receives a gold standard test that can serve as a comparator in estimating screening test accuracy. Thus, many studies of screening test accuracy use the passage of time to infer whether or not cancer was present at the time of the screening test, particularly for patients with a negative screening test. We define the accuracy assessment interval as the period of time after a screening test that is used to estimate the test's accuracy. We describe how the length of this interval may bias sensitivity and specificity estimates. We call for future research to quantify bias and uncertainty in accuracy estimates and to provide guidance on setting accuracy assessment interval lengths for different cancers and screening modalities.

Cancer screening in the U.S. through the COVID-19 pandemic, recovery, and beyond

COVID-19 has proved enormously disruptive to the provision of cancer screening, which does not just represent an initial test but an entire process, including risk detection, diagnostic follow-up, and treatment. Successful delivery of services at all points in the process has been negatively affected by the pandemic. There is a void in empirical high-quality evidence to support a specific strategy for administering cancer screening during a pandemic and its resolution phase, but several pragmatic considerations can help guide prioritization efforts. Targeting guideline-eligible people who have never been screened, or those who are significantly out of date with screening, has the potential to maximize benefits now and into the future. Disruptions to care due to the pandemic could represent an unparalleled opportunity to reassess early detection programs towards an explicit, thoughtful, and just prioritization of populations historically experiencing cancer disparities. By focusing screening services on populations that have the most to gain, and by careful and deliberate planning for the period following the pandemic, we can positively affect cancer outcomes for all.

Community-based lung cancer screening adherence to Lung-RADS recommendations

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Background: In the NLST and NELSON trials, most low-dose CT (LDCT) screen-detected lung cancers were not diagnosed during the first round of screening, suggesting that longitudinal adherence to lung cancer screening (LCS) recommendations is key. Adherence was as high as 95% in clinical trials, but limited data exist regarding LCS adherence in clinical practice. We aimed to determine adherence to Lung-RADS recommendations among community-based patients undergoing LCS. Methods: We performed a multicenter retrospective cohort study of patients screened for lung cancer at healthcare systems within the Lung Population-based Research to Optimize the Screening Process (PROSPR) Consortium. We included 55-80 year-old current or former smokers who received a baseline (T0) LDCT with a Lung-RADS score between January 1, 2015 and September 30, 2017 and excluded patients who were diagnosed with lung cancer prior to the T0 scan. Over a 24-month period, we calculated the proportion of patients adherent to Lung-RADS recommendations and evaluated associations with patient-level (age, sex, race, ethnicity, smoking status, body mass index, Elixhauser comorbidities, year of T0 scan, and Lung-RADS score) and census tract (median family income, level of education) data, using multivariable logistic regression with mixed effects to account for site variability. Results: Of the 6,723 patients in our cohort (median age 65 years [IQR 60-69]; 45.1% female; 73.0% white; 59.0% current smokers), 5,583 (83.0%) had Lung-RADS 1 or 2 T0 scans, 733 (10.9%) Lung-RADS 3, 274 (4.1%) Lung-RADS 4A, and 133 (2.0%) Lung-RADS 4B or 4X. Overall, 55.2% (3,709/6,723) of patients were adherent (Table). In the final multivariable model, Black patients had reduced adherence compared to white patients (adjusted odds ratio [aOR] 0.79, 95% CI 0.66-0.94), while greater adherence was observed in former smokers compared to current smokers (aOR 1.33, 95% 1.19-1.49). Compared to individuals with a negative T0 scan (Lung-RADS 1 or 2), those with Lung-RADS 3 (aOR 1.56, 95% CI 1.31-1.86), 4A (aOR 1.63, 95% CI 1.24-2.15), or 4B/4X (aOR 3.59, 95% CI 2.30-5.60) T0 scans had greater odds of adherence. Conclusions: In the largest study of real-world patients receiving LCS to date, adherence to Lung-RADS recommendations is lower than previously observed in clinical trials. Our results highlight the need for further study of system-level mechanisms to improve longitudinal LCS adherence rates.[Table: see text]

Evaluating Progestogens for Preventing Preterm birth International Collaborative (EPPPIC): meta-analysis of individual participant data from randomised controlled trials

BACKGROUND

Preterm birth is a global health priority. Using a progestogen during high-risk pregnancy could reduce preterm birth and adverse neonatal outcomes.

METHODS

We did a systematic review of randomised trials comparing vaginal progesterone, intramuscular 17-hydroxyprogesterone caproate (17-OHPC), or oral progesterone with control, or with each other, in asymptomatic women at risk of preterm birth. We identified published and unpublished trials that completed primary data collection before July 30, 2016, (12 months before data collection began), by searching MEDLINE, Embase, CINAHL, the Maternity and Infant Care Database, and relevant trial registers between inception and July 30, 2019. Trials of progestogen to prevent early miscarriage or immediately-threatened preterm birth were excluded. Individual participant data were requested from investigators of eligible trials. Outcomes included preterm birth, early preterm birth, and mid-trimester birth. Adverse neonatal sequelae associated with early births were assessed using a composite of serious neonatal complications, and individually. Adverse maternal outcomes were investigated as a composite and individually. Individual participant data were checked and risk of bias assessed independently by two researchers. Primary meta-analyses used one-stage generalised linear mixed models that incorporated random effects to allow for heterogeneity across trials. This meta-analysis is registered with PROSPERO, CRD42017068299.

FINDINGS

Initial searches identified 47 eligible trials. Individual participant data were available for 30 of these trials. An additional trial was later included in a targeted update. Data were therefore available from a total of 31 trials (11 644 women and 16185 offspring). Trials in singleton pregnancies included mostly women with previous spontaneous preterm birth or short cervix. Preterm birth before 34 weeks was reduced in such women who received vaginal progesterone (nine trials, 3769 women; relative risk [RR] 0·78, 95% CI 0·68-0·90), 17-OHPC (five trials, 3053 women; 0·83, 0·68-1·01), and oral progesterone (two trials, 181 women; 0·60, 0·40-0·90). Results for other birth and neonatal outcomes were consistently favourable, but less certain. A possible increase in maternal complications was suggested, but this was uncertain. We identified no consistent evidence of treatment interaction with any participant characteristics examined, although analyses within subpopulations questioned efficacy in women who did not have a short cervix. Trials in multifetal pregnancies mostly included women without additional risk factors. For twins, vaginal progesterone did not reduce preterm birth before 34 weeks (eight trials, 2046 women: RR 1·01, 95% CI 0·84-1·20) nor did 17-OHPC for twins or triplets (eight trials, 2253 women: 1·04, 0·92-1·18). Preterm premature rupture of membranes was increased with 17-OHPC exposure in multifetal gestations (rupture <34 weeks RR 1·59, 95% CI 1·15-2·22), but we found no consistent evidence of benefit or harm for other outcomes with either vaginal progesterone or 17-OHPC.

INTERPRETATION

Vaginal progesterone and 17-OHPC both reduced birth before 34 weeks' gestation in high-risk singleton pregnancies. Given increased underlying risk, absolute risk reduction is greater for women with a short cervix, hence treatment might be most useful for these women. Evidence for oral progesterone is insufficient to support its use. Shared decision making with woman with high-risk singleton pregnancies should discuss an individual's risk, potential benefits, harms and practicalities of intervention. Treatment of unselected multifetal pregnancies with a progestogen is not supported by the evidence.

FUNDING

Patient-Centered Outcomes Research Institute.

Collaborative Modeling: Experience of the U.S. Preventive Services Task Force

Models can be valuable tools to address uncertainty, trade-offs, and preferences when trying to understand the effects of interventions. Availability of results from two or more independently developed models that examine the same question (comparative modeling) allows systematic exploration of differences between models and the effect of these differences on model findings. Guideline groups sometimes commission comparative modeling to support their recommendation process. In this commissioned collaborative modeling, modelers work with the people who are developing a recommendation or policy not only to define the questions to be addressed but ideally, work side-by-side with each other and with systematic reviewers to standardize selected inputs and incorporate selected common assumptions. This paper describes the use of commissioned collaborative modeling by the U.S. Preventive Services Task Force (USPSTF), highlighting the general challenges and opportunities encountered and specific challenges for some topics. It delineates other approaches to use modeling to support evidence-based recommendations and the many strengths of collaborative modeling compared with other approaches. Unlike systematic reviews prepared for the USPSTF, the commissioned collaborative modeling reports used by the USPSTF in making recommendations about screening have not been required to follow a common format, sometimes making it challenging to understand key model features. This paper presents a checklist developed to critically appraise commissioned collaborative modeling reports about cancer screening topics prepared for the USPSTF.

Screening for prostate cancer: a review of the evidence for the U.S. Preventive Services Task Force

BACKGROUND

Screening can detect prostate cancer at earlier, asymptomatic stages, when treatments might be more effective.

PURPOSE

To update the 2002 and 2008 U.S. Preventive Services Task Force evidence reviews on screening and treatments for prostate cancer.

DATA SOURCES

MEDLINE (2002 to July 2011) and the Cochrane Library Database (through second quarter of 2011).

STUDY SELECTION

Randomized trials of prostate-specific antigen-based screening, randomized trials and cohort studies of prostatectomy or radiation therapy versus watchful waiting, and large observational studies of perioperative harms.

DATA EXTRACTION

Investigators abstracted and checked study details and quality using predefined criteria.

DATA SYNTHESIS

Of 5 screening trials, the 2 largest and highest-quality studies reported conflicting results. One found that screening was associated with reduced prostate cancer-specific mortality compared with no screening in a subgroup of men aged 55 to 69 years after 9 years (relative risk, 0.80 [95% CI, 0.65 to 0.98]; absolute risk reduction, 0.07 percentage point). The other found no statistically significant effect after 10 years (relative risk, 1.1 [CI, 0.80 to 1.5]). After 3 or 4 screening rounds, 12% to 13% of screened men had false-positive results. Serious infections or urine retention occurred after 0.5% to 1.0% of prostate biopsies. There were 3 randomized trials and 23 cohort studies of treatments. One good-quality trial found that prostatectomy for localized prostate cancer decreased risk for prostate cancer-specific mortality compared with watchful waiting through 13 years of follow-up (relative risk, 0.62 [CI, 0.44 to 0.87]; absolute risk reduction, 6.1%). Benefits seemed to be limited to men younger than 65 years. Treating approximately 3 men with prostatectomy or 7 men with radiation therapy instead of watchful waiting would each result in 1 additional case of erectile dysfunction. Treating approximately 5 men with prostatectomy would result in 1 additional case of urinary incontinence. Prostatectomy was associated with perioperative death (about 0.5%) and cardiovascular events (0.6% to 3%), and radiation therapy was associated with bowel dysfunction.

LIMITATIONS

Only English-language articles were included. Few studies evaluated newer therapies.

CONCLUSION

Prostate-specific antigen-based screening results in small or no reduction in prostate cancer-specific mortality and is associated with harms related to subsequent evaluation and treatments, some of which may be unnecessary.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Screening for prostate cancer with PSA testing: current status and future directions

The ultimate utility of the serum prostate specific antigen (PSA) assay as a screening test for reducing prostate cancer mortality has been an area of intense controversy since its introduction. PSA testing was not initially envisioned as a screening tool, but as a way to evaluate treatment responses in men with prostate cancer. Far in advance of evidence from randomized trials, the rapid and widespread uptake of PSA screening into US practice was initially driven by the intuitively logical assumption that the earlier one detects a malignancy, the more likely treatment is to be curative while minimizing associated harms. However, a growing body of observational evidence began to point to a substantial burden of associated overdiagnosis and overtreatment triggered by PSA testing. The interim results of several randomized clinical trials specifically designed to evaluate the impact of PSA testing on prostate cancer mortality have recently become available, but their incongruent results seem to have added fuel to the debate. This article presents a review of the literature on screening for prostate cancer with PSA testing; we include a detailed discussion of potential explanations for the contradictory results of the two largest randomized trials as well as reflections on the future of prostate cancer screening.

Principles of cancer screening: lessons from history and study design issues

Early detection of cancer has held great promise and intuitive appeal in the medical community for well over a century. Its history developed in tandem with that of the periodic health examination, in which any deviations--subtle or glaring--from a clearly demarcated "normal" were to be rooted out, given the underlying hypothesis that diseases develop along progressive linear paths of increasing abnormalities. This model of disease development drove the logical deduction that early detection, by "breaking the chain" of cancer development, must be of benefit to affected individuals. In the latter half of the 20th century, researchers and guidelines organizations began to explicitly challenge the core assumptions underpinning many clinical practices. A move away from intuitive thinking began with the development of evidence-based medicine. One key method developed to explicitly quantify the overall risk-benefit profile of a given procedure was the analytic framework. The shift away from pure deductive reasoning and reliance on personal observation was driven, in part, by a rising awareness of critical biases in cancer screening that can mislead clinicians, including healthy volunteer bias, length-biased sampling, lead-time bias, and overdiagnosis. A new focus on the net balance of both benefits and harms when determining the overall worth of an intervention also arose: it was recognized that the potential downsides of early detection were frequently overlooked or discounted because screening is performed on basically healthy persons and initially involves relatively noninvasive methods. Although still inconsistently applied to early detection programs, policies, and belief systems in the United States, an evidence-based approach is essential to counteract the misleading--even potentially harmful--allure of intuition and individual observation.

Cumulative incidence of false-positive test results in lung cancer screening: a randomized trial

BACKGROUND

Direct-to-consumer promotion of lung cancer screening has increased, especially low-dose computed tomography (CT). However, screening exposes healthy persons to potential harms, and cumulative false-positive rates for low-dose CT have never been formally reported.

OBJECTIVE

To quantify the cumulative risk that a person who participated in a 1- or 2-year lung cancer screening examination would receive at least 1 false-positive result, as well as rates of unnecessary diagnostic procedures.

DESIGN

Randomized, controlled trial of low-dose CT versus chest radiography. (ClinicalTrials.gov registration number: NCT00006382)

SETTING

Feasibility study for the ongoing National Lung Screening Trial.

PATIENTS

Current or former smokers, aged 55 to 74 years, with a smoking history of 30 pack-years or more and no history of lung cancer (n = 3190).

INTERVENTION

Random assignment to low-dose CT or chest radiography with baseline and 1 repeated annual screening; 1-year follow-up after the final screening. Randomization was centralized and stratified by age, sex, and study center.

MEASUREMENTS

False-positive screenings, defined as a positive screening with a completed negative work-up or 12 months or more of follow-up with no lung cancer diagnosis.

RESULTS

By using a Kaplan-Meier analysis, a person's cumulative probability of 1 or more false-positive low-dose CT examinations was 21% (95% CI, 19% to 23%) after 1 screening and 33% (CI, 31% to 35%) after 2. The rates for chest radiography were 9% (CI, 8% to 11%) and 15% (CI, 13% to 16%), respectively. A total of 7% of participants with a false-positive low-dose CT examination and 4% with a false-positive chest radiography had a resulting invasive procedure.

LIMITATIONS

Screening was limited to 2 rounds. Follow-up after the second screening was limited to 12 months. The false-negative rate is probably an underestimate.

CONCLUSION

Risks for false-positive results on lung cancer screening tests are substantial after only 2 annual examinations, particularly for low-dose CT. Further study of resulting economic, psychosocial, and physical burdens of these methods is warranted.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Clinical trial design and evidence-based outcomes in the study of liver diseases

Current medical training often does not include the formal study of trial design, forcing clinicians to acquire this knowledge independently. This article reviews the foundational elements of clinical trial design. An overarching hierarchy of clinical evidence is introduced, and the relative strengths and limitations of the major types of study designs are discussed. A corollary to the hierarchy of evidence in trial designs is proposed for trial outcomes: the "pyramid of endpoints." This pyramid represents a spectrum of outcomes from tangible health events to intermediate markers with no direct physical impact on an individual. The potential advantages and difficulties inherent in the use of surrogate endpoints for final health outcomes are explored. Randomized controlled trials utilizing "hard" clinical endpoints are advocated as the most efficient and reliable way to directly assess the benefits and harms of a therapy; however, using a case study of treatments for hepatocellular carcinoma, we highlight the challenges that can complicate even the highest levels of evidence. All trials have a "signal-to-noise" ratio - this review emphasizes the need for careful and deliberate consideration of the potential limitations of every study, and provides basic tools to assist the practitioner in identifying common pitfalls of clinical trials.