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A direct comparison of American Cancer Society (ACS), American College of Chest Physicians (ACCP), Canadian Task Force on Preventive Health Care (CTFPHC), and U.S. Preventive Services Task Force (USPSTF) recommendations for lung cancer screening in asymptomatic patients is provided in the tables below. The guidelines differ somewhat in scope and focus, with some of the guidelines offering recommendations beyond screening. For example, ACCP's lung cancer screening guideline represents just one chapter from a more comprehensive guideline supplement including recommendations related to lung cancer prevention, diagnosis, initial evaluation and staging, treatment, follow-up/surveillance, palliative treatment, and end of life care. In addition to the interventions compared in this synthesis (chest x-ray, sputum cytology, and low-dose computed tomography), the ACS, ACCP and USPSTF guidelines include discussion of other detection methods such as fluorescence bronchoscopy and biomolecular marker screening, though no formal recommendations regarding these techniques are made.
ACS released its guidance on early lung cancer detection in response to recommendations resulting from the 1998 International Conference on the Prevention and Early Diagnosis of Lung Cancer held in Varese, Italy which called for "national governments and public health organizations involved in cancer prevention and control to more aggressively address tobacco control and to urgently consider the issues surrounding the early detection of lung cancer."
ACCP, CTFPHC, and USPSTF each considered ACS recommendations when developing and/or updating their own recommendations. ACCP also reviewed USPSTF's 2004 recommendations; CTFPHC likewise reviewed USPSTF's 1996 recommendations as well as the 2003 version of ACCP's guideline. USPSTF refers readers to recommendations issued by CTFPHC and ACS.
The tables below provide a side-by-side comparison of key attributes of each guideline, including specific interventions and practices that are addressed. The language used in these tables, particularly that which is used in Table 3, Table 4, and Table 5, is in most cases taken verbatim from the original guidelines.
A summary discussion of the areas of agreement and areas of differences among the guidelines is presented following the content comparison tables.
Listed below are common abbreviations used within the tables and discussions:
TABLE 1: COMPARISON OF INTERVENTIONS AND PRACTICES CONSIDERED ("" indicates topic is addressed) |
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ACS (2001) | ACCP (2007) | CTFPHC (2003) | USPSTF (2004) | |
CXR |
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LDCT |
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Sputum cytology |
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TABLE 3: COMPARISON OF RECOMMENDATIONS FOR LUNG CANCER SCREENING | |
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ACS (2001) |
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ACCP (2007) |
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CTFPHC (2003) |
Chest X-ray The CTFPHC concludes that there is fair evidence to recommend against screening asymptomatic people for lung cancer using chest radiographic examination. (D recommendation) (Manser et al., 2002 [I, fair]; Kubik, Parkin, & Zatloukal, 2000 [I, fair]; Marcus et al., 2000 [I, fair]; Nishii et al., 2001 [II-2, fair]; Okamoto et al., 1999 [II-2, fair]; Sagawa et al., 2001 [II-2, fair]; Sobue, 2000 [II-2, fair]; Tsukada et al., 2001 [II-2, fair]). Low Dose Computed Tomography The CTFPHC concludes that there is insufficient evidence (in quantity and/or quality) to make a recommendation as to whether spiral CT scanning should be used for screening asymptomatic people for lung cancer. However, other factors may influence decision-making. (I recommendation). (Henschke et al., 1999; Henschke et al., 2001; Sone et al., 1998; Sone et al., 2001; Diederich et al., 2000 [II-2, III]). |
USPSTF (2004) |
The USPSTF concludes that the evidence is insufficient to recommend for or against screening asymptomatic persons for lung cancer with either LDCT, CXR, sputum cytology, or a combination of these tests. I recommendation Clinical Considerations
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TABLE 5: EVIDENCE RATING SCHEMES AND REFERENCES | |
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ACCP (2007) |
Quality of Evidence Scale High (A) Randomized controlled trials (RCTs) without important limitations or overwhelming evidence from observational studies Moderate (B) RCTs with important limitations (inconsistent results, methodologic flaws, indirect, or imprecise) or exceptionally strong evidence from observational studies Low or very low (C) Observational studies or case series Strength of Recommendations 1A - Strong recommendation 1B - Strong recommendation 1C - Strong recommendation 2A - Weak recommendation 2B - Weak recommendation 2C - Weak recommendation |
CTFPHC (2003) |
Levels of Evidence - Research Design Rating I: Evidence from randomized controlled trials (RCT) II-1: Evidence from controlled trials without randomization II-2: Evidence from cohort or case-control analytic studies, preferably from more than 1 centre or research group II-3: Evidence from comparisons between times or places with or without the intervention; dramatic results in uncontrolled experiments could also be included here III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees Quality (Internal Validity) Rating Good: A study that meets all design-specific criteria* well Fair: A study that does not meet (or it is not clear that it meets) at least one design-specific criterion* but has no known "fatal flaw" Poor: A study that has at least one design-specific* "fatal flaw," or an accumulation of lesser flaws to the extent that the results of the study are not deemed able to inform recommendations *General design-specific criteria are outlined in Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow CD, Teutsch SM, Atkins D. Current Methods of the U.S. Preventive Services Task Force: A Review of the Process. Am J Prev Med 2001;20(suppl 3):21-35. Recommendations Grades for Specific Clinical Preventive Actions A: The Canadian Task Force (CTF) concludes that there is good evidence to recommend the clinical preventive action. B: The CTF concludes that there is fair evidence to recommend the clinical preventive action. C: The CTF concludes that the existing evidence is conflicting and does not allow making a recommendation for or against use of the clinical preventive action; however, other factors may influence decision-making. D: The CTF concludes that there is fair evidence to recommend against the clinical preventive action. E: The CTF concludes that there is good evidence to recommend against the clinical preventive action. I: The CTF concludes that there is insufficient evidence (in quantity and/or quality) to make a recommendation; however, other factors may influence decision-making. References
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USPSTF (2004) |
The USPSTF grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor): Good Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes. Fair Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes. Poor Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes. The USPSTF grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms): A The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms. B The USPSTF recommends that clinicians provide [the service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health outcomes and concludes that benefits outweigh harms. C The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes that the balance of benefits and harms is too close to justify a general recommendation. D The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh benefits. I The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that [the service] is effective is lacking, of poor quality, or conflicting and the balance of benefits and harms cannot be determined. |
The American Cancer Society (ACS), American College of Chest Physicians (ACCP), Canadian Task Force on Preventive Health Care (CTFPHC) and the U.S. Preventive Services Task Force (USPSTF) present recommendations for screening for lung cancer based on evidence available at the time of each report and provide explicit reasoning behind their judgments. ACCP, CTFPHC, and USPSTF rate the quality of their recommendations and the type of evidence supporting them; CTFPHC also provides literature citations to support their major recommendations. ACS recommendations are provided in narrative form. Both ACCP and USPSTF include a review of the evidence supporting their recommendations. ACCP, CTFPHC, and USPSTF all provide comparisons with other national guidelines, including ACS's recommendations.
The four groups are in general agreement regarding the inappropriateness of routine lung cancer screening in asymptomatic individuals. ACS specifically recommends against any routine screening, while the other three make recommendations based on specific diagnostic tests. All guidelines note the need for more research into the effectiveness of screening for lung cancer, most notably, randomized controlled trials on LDCT. ACS and USPSTF mention the National Cancer Institute's Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial as a prospective study that may eventually provide additional insight. ACCP addresses the National Cancer Institute's National Lung Screening Trial (NLST).
None of the four guidelines recommends CXR to screen for lung cancer in asymptomatic patients. Both ACCP and CTFPHC explicitly recommend against screening for lung cancer with CXR, while USPSTF concludes that there is insufficient evidence to recommend for or against screening for lung cancer with chest x-ray. Although ACS makes no specific recommendations concerning CXR, they do not recommend any routine screening, though they note that individual patients and physicians may decide that the evidence warrants screening on an individual basis.
All four guidelines agree directly or indirectly that LDCT is more sensitive than CXR in detecting lung cancer. Each group however, acknowledges that this greater test sensitivity may be associated with a higher rate of false positives, which may result in the use of additional diagnostic procedures that carry a significant risk of harms. Each of the guidelines further note that currently, the evidence is not yet sufficient to determine whether or not detection of smaller lung cancers with LDCT reduces lung cancer mortality.
ACCP does not recommend that LDCT be used to screen for lung cancer except in the context of a well-designed clinical trial. CTFPHC and USPSTF conclude that there is insufficient evidence to recommend for or against the use of LDCT to screen asymptomatic patients at risk for lung cancer. ACS expresses concern that this technology may disseminate broadly before the technology is validated and encourages individuals interested in early detection to participate in clinical trials.
None of the four guidelines recommend the use of sputum cytology for screening for lung cancer. ACCP explicitly recommends against its use, while USPSTF finds insufficient evidence to recommend for or against the technology. ACS further notes that one disadvantage of this technology is that positive test results require additional testing to identify location of the cancer. CTFPHC offers no recommendations regarding sputum cytology.
While not described in the table above, it is important to note that all of the developers included in this comparison emphasize that smoking cessation is the best way to reduce lung cancer mortality at this time.
While all four guidelines are in general agreement about the lack of evidence supporting the efficacy of lung cancer screening, ACS makes a distinction between its recommendation against mass screening and decisions made by individual patients and their doctors, noting that their recommendations are not intended to discourage individuals from having early detection tests if they and their doctors determine that testing is appropriate. However, ACS notes that because of increasing availability and promotion of testing, it is critically important that individuals who are interested in testing understand both the potential benefits of screening with LDCT, as well as potential harms associated with diagnostic procedures and treatment. ACS offers guidance for patients and their doctors, and discourages testing in a setting that is not linked to multidisciplinary specialty groups for diagnosis and follow-up. ACS further states that individuals who decide to undergo testing should have access to state-of-the art testing and follow-up.
ACCP also notes that the election to screen an individual who is at risk for lung cancer should be based on shared, informed decision making between provider and patient.
This Synthesis was prepared by ECRI on October 8, 2005. This synthesis was verified by: CTFPHC on November 2, 2005; ACCP on November 28, 2005; USPSTF on November 30, 2005; and ACS on December 2, 2005. This synthesis was revised on January 13, 2008 to update ACCP recommendations.
Internet citation: National Guideline Clearinghouse (NGC). Guideline synthesis: Screening for lung cancer. In: National Guideline Clearinghouse (NGC) [website]. Rockville (MD): 2005 Dec (revised 2008 Feb). [cited YYYY Mon DD]. Available: http://www.guideline.gov.