USPSTF Recommends Lung Cancer Screening with Low-dose CT

New Criteria Increase Patient Eligibility

March 25, 2021, 5:47 p.m. News Staff — On March 9, the U.S. Preventive Services Task Force issued a final recommendation statement, final evidence review, final modeling report, modeling study and evidence summary on screening for lung cancer with low-dose CT.

In December 2013, the USPSTF recommended annual screening for lung cancer with LDCT in adults ages 55 to 80 who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years – a “B”-level recommendation.

To update the 2013 recommendation, the task force commissioned a systematic review to examine the accuracy of screening with low-dose CT in populations and the benefits and harms of screening for lung cancer. The review also assessed whether the benefits of screening varied by subgroups such as race or sex or by the number or frequency of low-dose CT scans, and whether the harms associated with screening and the evaluation of lung nodules differ based on the type of approach used.

In addition to the evidence review, the USPSTF commissioned a collaborative modeling study from investigators of the Cancer Intervention and Surveillance Modeling Network Lung Group to provide information on a number of variables, including:

• optimal age at which to begin and end screening,
• optimal screening interval, and
• relative benefits and harms of different screening strategies.

The review included English-language studies from PubMed, Medline and the Cochrane Library, and trial registries through May 28, 2019. Other data sources included reference lists of retrieved articles, outside experts and reviewers, with literature surveillance conducted through Nov. 20, 2020.

The evidence review included 223 publications. Seven randomized clinical trials evaluated lung cancer screening with low-dose CT; of those, only the National Lung Screening Trial and the NELSON (Nederlands-Leuvens Longkanker Screenings Onderzoek) study were adequately powered.

Findings

Overall, the evidence review found that screening those at high risk for lung cancer with low-dose CT can reduce lung cancer mortality and may reduce all-cause mortality. However, screening also causes false-positive results that may lead to unnecessary tests, invasive procedures, overdiagnosis, incidental findings, increases in patient distress or anxiety and, in rare instances, radiation-induced cancers.

The evidence for benefits of lung cancer screening was found to have come primarily from the NLST and NELSON studies. However, the researchers noted that these trials had limited racial and ethnic diversity, and that the trial participants were younger and less likely to be current smokers than the U.S. screening-eligible population. It also was noted that these trials were conducted mainly at large academic centers, which could potentially limit their applicability in the community setting.

The review also found that application of lung cancer screening with current nodule management protocols such as Lung-RADS might improve the balance of benefits and harms. However, most studies reviewed did not use current protocols.

Eligibility for Screening Increased

Based on the findings in the evidence review, the task force made two notable changes regarding screening eligibility. First, the new recommendation lowers the age at which the task force recommends that annual screening for lung cancer begin from 55 to 50. Second, the new recommendation lowers the number of pack years of smoking history that makes an individual eligible for screening from 30 to 20.

Based on the expanded screening criteria, the task force stated in its press release that these changes will nearly double the number of people eligible for lung cancer screening. The new screening criteria could also prove beneficial to Black patients, as recent research has indicated that collectively, Black individuals have the highest death rates and shortest survival times of any racial or ethnic group in the United States for most cancers.

“The changes to this recommendation mean more Black people and women are now eligible for lung cancer screening, which is a step in the right direction,” said John Wong, M.D., a task force member. “However, to save more lives and ensure that everyone who would benefit is screened, it is critical that screening is implemented broadly and equitably.”

Results from the CISNET modeling study provided additional data in support of screening with low-dose CT.  The modeling analysis indicated that low-dose CT screening could lead to important reductions in lung cancer death and result in significant life years gained when optimally targeted. In particular, the analysis found that lung cancer screening in individuals ages 50 or 55 through 80 with 20 or more pack-years of smoking exposure would result in more benefits than in screening using the criteria in the USPSTF’s 2013 recommendation, and that it would reduce disparities in eligibility by sex and race or ethnicity.

Additional Research Needed

The task force concluded that several research gaps need to be addressed. Specifically, the task force noted that further research is needed to

• address how to increase the uptake of lung cancer screening discussions in clinical practice, particularly among populations that are at increased risk of death from lung cancer or that are socially and economically disadvantaged;
• evaluate whether the balance of benefits and harms of lung cancer screening observed in randomized controlled trials differs from those observed when screening is implemented in more diverse community settings;
• identify biomarkers that can accurately indicate individuals at increased risk;
• identify technologies that can better differentiate between benign and malignant lung nodules; and
• determine the benefits and harms of using risk prediction models to select patients for lung cancer screening.

Response to Public Comment

A draft version of the recommendation statement was posted for public comment on the USPSTF website from July 7, 2020, to Aug. 3, 2020.

Some individuals commented on broadening the eligibility criteria for lung cancer screening, while others mentioned that additional risk factors for lung cancer other than smoking exist or that lung cancer can occur in people who never smoked. In response, the USPSTF said the current evidence does not support incorporation of these risk factors as determinants of eligibility for lung cancer screening. The task force also said smoking is the major risk factor for lung cancer, that all trials of screening for lung cancer have been conducted among current or former smokers, and that trial and modeling data support the current USPSTF recommendation as offering a reasonable balance of benefits and harms.

In response to a suggestion that the task force use more complex risk prediction models to determine eligibility for lung cancer screening, the USPSTF provided language clarifying that use of these risk production models might make implementation more difficult, and that there are currently no lung cancer screening trials prospectively comparing USPSTF eligibility criteria with risk prediction models.

The USPSTF also added information on the effect of the current recommendation on screening eligibility in Latinx/Hispanic individuals, and provided links to several new tools and websites from the CDC and other organizations, including

• How to Quit Smoking,
• Lung Cancer Screening (PDQ) – Health Professional Version and Patient Version, 
• Smoking Cessation: Fast Facts, and
• Tips From Former Smokers.
  

Up Next

The AAFP did not support the USPSTF’s 2013 recommendation statement, which based its findings primarily on the results of the NLST. Instead, the Academy reviewed the available evidence at the time and concluded that there was insufficient evidence to recommend for or against screening for lung cancer with low-dose CT.

In response to the new final recommendation statement, Academy President Ada Stewart, M.D., of Columbia, S.C., said it is AAFP policy to wait until a final recommendation and evidence review are published before the Academy updates its own recommendations. The AAFP, Stewart added, has not updated its lung cancer screening recommendation since 2013 because it has been waiting for the USPSTF to conduct a comprehensive evidence review, which would allow the Academy to assess the totality of the evidence. 

Now that the task force’s evidence review has been published, the Academy is working on updating its own recommendation. Once that update is complete, the recommendation will be published on AAFP.org and members will be notified.

"The AAFP Commission on Health of the Public and Science is conducting a thorough review of the final updated USPSTF recommendation and evidence report, so it may be several weeks before a final decision is made," Stewart told USA Today in a story published March 9.