NCA - Screening for Lung Cancer with Low Dose Computed Tomography (LDCT) (CAG-00439R) - Decision Memo

APPENDIX AGeneral Methodological Principles of Study Design(Section VI of the Decision Memorandum)When making national coverage determinations, CMS evaluates relevant clinical evidence to determine whether or not the evidence is of sufficient quality to support a finding that an item or service is reasonable and necessary. The overall objective for the critical appraisal of the evidence is to determine to what degree we are confident that: 1) the specific assessment questions can be answered conclusively; and 2) the intervention will improve health outcomes for patients.We divide the assessment of clinical evidence into three stages: 1) the quality of the individual studies; 2) the generalizability of findings from individual studies to the Medicare population; and 3) overarching conclusions that can be drawn from the body of the evidence on the direction and magnitude of the interventions potential risks and benefits.The methodological principles described below represent a broad discussion of the issues we consider when reviewing clinical evidence. However, it should be noted that each coverage determination has its unique methodological aspects.Assessing Individual StudiesMethodologists have developed criteria to determine weaknesses and strengths of clinical research. Strength of evidence generally refers to: 1) the scientific validity underlying study findings regarding causal relationships between health care interventions and health outcomes; and 2) the reduction of bias. In general, some of the methodological attributes associated with stronger evidence include those listed below:Use of randomization (allocation of patients to either intervention or control group) in order to minimize bias.Use of contemporaneous control groups (rather than historical controls) in order to ensure comparability between the intervention and control groups.Prospective (rather than retrospective) studies to ensure a more thorough and systematical assessment of factors related to outcomes.Larger sample sizes in studies to demonstrate both statistically significant as well as clinically significant outcomes that can be extrapolated to the Medicare  population. Sample size should be large enough to make chance an unlikely explanation for what was found.Masking (blinding) to ensure patients and investigators do not know to that group patients were assigned (intervention or control). This is important especially in subjective outcomes, such as pain or quality of life, where     enthusiasm and psychological factors may lead to an improved perceived     outcome by either the patient or assessor.Regardless of whether the design of a study is a randomized controlled trial, a non-randomized controlled trial, a cohort study or a case-control study, the primary criterion for methodological strength or quality is to the extent that differences between intervention and control groups can be attributed to the intervention studied. This is known as internal validity. Various types of bias can undermine internal validity. These include:Different characteristics between patients participating and those theoretically eligible for study but not participating (selection bias).Co-interventions or provision of care apart from the intervention under evaluation (performance bias).Differential assessment of outcome (detection bias).Occurrence and reporting of patients who do not complete the study (attrition bias).In principle, rankings of research design have been based on the ability of each study design category to minimize these biases. A randomized controlled trial minimizes systematic bias (in theory) by selecting a sample of participants from a particular population and allocating them randomly to the intervention and control groups. Thus, in general, randomized controlled studies have been typically assigned the greatest strength, followed by non-randomized clinical trials and controlled observational studies. The design, conduct and analysis of trials are important factors as well. For example, a well-designed and conducted observational study with a large sample size may provide stronger evidence than a poorly designed and conducted randomized controlled trial with a small sample size. The following is a representative list of study designs (some of that have alternative names) ranked from most to least methodologically rigorous in their potential ability to minimize systematic bias:Randomized controlled trialsNon-randomized controlled trialsProspective cohort studiesRetrospective case control studiesCross-sectional studiesSurveillance studies (e. g. , using registries or surveys)Consecutive case seriesSingle case reportsWhen there are merely associations but not causal relationships between a studys variables and outcomes, it is important not to draw causal inferences. Confounding refers to independent variables that systematically vary with the causal variable. This distorts measurement of the outcome of interest because its effect size is mixed with the effects of other extraneous factors.  For observational, and in some cases randomized controlled trials, the method in that confounding factors are handled (either through stratification or appropriate statistical modeling) are of particular concern. For example, in order to interpret and generalize conclusions to our population of Medicare patients, it may be necessary for studies to match or stratify their intervention and control groups by patient age or co-morbidities.Methodological strength is, therefore, a multidimensional concept that relates to the design, implementation and analysis of a clinical study. In addition, thorough documentation of the conduct of the research, particularly study selection criteria, rate of attrition and process for data collection, is essential for CMS to adequately assess and consider the evidence.Generalizability of Clinical Evidence to the Medicare PopulationThe applicability of the results of a study to other populations, settings, treatment regimens and outcomes assessed is known as external validity.  Even well-designed and well-conducted trials may not supply the evidence needed if the results of a study are not applicable to the Medicare population.  Evidence that provides accurate information about a population or setting not well represented in the Medicare program would be considered but would suffer from limited generalizability.The extent to that the results of a trial are applicable to other circumstances is often a matter of judgment that depends on specific study characteristics, primarily the patient population studied (age, sex, severity of disease and presence of co-morbidities) and the care setting (primary to tertiary level of care, as well as the experience and specialization of the care provider). Additional relevant variables are treatment regimens (dosage, timing and route of administration), co-interventions or concomitant therapies, and type of outcome and length of follow-up.The level of care and the experience of the providers in the study are other crucial elements in assessing a studys external validity. Trial participants in an academic medical center may receive more or different attention than is typically available in non-tertiary settings. For example, an investigators lengthy and detailed explanations of the potential benefits of the intervention and/or the use of new equipment provided to the academic center by the study sponsor may raise doubts about the applicability of study findings to community practice.Given the evidence available in the research literature, some degree of generalization about an interventions potential benefits and harms is invariably required in making coverage determinations for the Medicare population. Conditions that assist us in making reasonable generalizations are biologic plausibility, similarities between the populations studied and Medicare patients (age, sex, ethnicity and clinical presentation) and similarities of the intervention studied to those that would be routinely available in community practice.A studys selected outcomes are an important consideration in generalizing available clinical evidence to Medicare coverage determinations. One of the goals of our determination process is to assess health outcomes. These outcomes include resultant risks and benefits such as increased or decreased morbidity and mortality. In order to make this determination, it is often necessary to evaluate whether the strength of the evidence is adequate to draw conclusions about the direction and magnitude of each individual outcome relevant to the intervention under study. In addition, it is important that an interventions benefits are clinically significant and durable, rather than marginal or short-lived. Generally, an intervention is not reasonable and necessary if its risks outweigh its benefits.If key health outcomes have not been studied or the direction of clinical effect is inconclusive, we may also evaluate the strength and adequacy of indirect evidence linking intermediate or surrogate outcomes to our outcomes of interest.Assessing the Relative Magnitude of Risks and BenefitsGenerally, an intervention is not reasonable and necessary if its risks outweigh its benefits. Health outcomes are one of several considerations in determining whether an item or service is reasonable and necessary. CMS places greater emphasis on health outcomes actually experienced by patients, such as quality of life, functional status, duration of disability, morbidity and mortality, and less emphasis on outcomes that patients do not directly experience, such as intermediate outcomes, surrogate outcomes, and laboratory or radiographic responses. The direction, magnitude, and consistency of the risks and benefits across studies are also important considerations. Based on the analysis of the strength of the evidence, CMS assesses the relative magnitude of an intervention or technologys benefits and risk of harm to Medicare beneficiaries.APPENDIX BMedicare National Coverage Determinations ManualDraftThis draft NCD is subject to formal revisions and formatting changes prior to the release of the final NCD contractor instructions and publication in the Medicare National Coverage Determinations Manual.Table of Contents(Rev.)210.14  Lung Cancer Screening with Low Dose Computed Tomography (LDCT)A. GeneralLung cancer is the third most common cancer and the leading cause of cancer deaths in the United States. Cancer of the lung and bronchus accountedfor over 130,000 deaths in 2021 (more than the total number of estimated deaths from colon, breast and prostate cancer combined)with a median age at death of 72 years. Computed tomography (CT) is an imaging procedure that uses specialized x-ray equipment to create detailed pictures of areas inside the body. Low dose computed tomography (LDCT) is a chest CT scan performed at settings to minimize radiation exposure compared to a standard chest CT. Under 1861(ddd) of the Social Security Act (the Act), the Centers for Medicare & Medicaid Services (CMS) has the authority to add coverage of additional preventive services through the Medicare national coverage determination (NCD) process if certain statutory requirements are met: (1) reasonable and necessary for the prevention or early detection of illness or disability, (2) recommended with a grade of A or B by the United States Preventive Services Task Force (USPSTF), and (3) appropriate for individuals entitled to benefits under Part A or enrolled under Part B.B. Nationally Covered IndicationsEffective for claims with dates of service on or after 2/10/2022 , CMS has determined that the evidence is sufficient to cover, under Medicare Part B, a lung cancer screening counseling and shared decision-making visit, and for appropriate beneficiaries, annual screening for lung cancer with LDCT, as an additional preventive service benefit under the Medicare program only if all of the following eligibility criteria are met.Beneficiary Eligibility CriteriaFor purposes of Medicare coverage of lung cancer screening with LDCT, beneficiaries must meet all of the following eligibility criteria:Age50 77 years;Asymptomatic (no signs or symptoms of lung cancer);Tobacco smoking history of at least20pack-years (one pack-year = smoking one pack per day for one year; 1 pack = 20 cigarettes);Current smoker or one who has quit smoking within the last 15 years; andReceive an order for lung cancer screening with LDCT.Counseling and Shared Decision-Making VisitBefore the beneficiarys first lung cancer LDCT screening, the beneficiary must receive a counseling and shared decision-making visit that meets all of the following criteria, and is appropriately documented in the beneficiarys medical records:Determination of beneficiary eligibility;Shared decision-making, including the use of one or more decision aids;Counseling on the importance of adherence to annual lung cancer LDCT screening, impact of comorbidities and ability or willingness to undergo diagnosis and treatment; andCounseling on the importance of maintaining cigarette smoking abstinence if former smoker; or the importance of smoking cessation if current smoker and, if appropriate, furnishing of information about tobacco cessation interventions.Reading Radiologist Eligibility CriteriaFor purposes of Medicare coverage of lung cancer screening with LDCT, the reading radiologist must have board certification or board eligibility with the American Board of Radiology or equivalent organization.Radiology Imaging Facility Eligibility CriteriaFor purposes of Medicare coverage,lung cancer screeningwith LDCT must be furnished in a radiology imaging facility that utilizes a standardized lung nodule identification, classification and reporting system.C. Nationally Non-Covered IndicationsPreventive services are non-covered by Medicare unless specifically covered in this NCD, any other NCD or in statute or regulations.D. OtherMedicare Part B coinsurance and deductible are waived for this preventive service.(This NCD last reviewed 02/10/2022.)