Are Lung Cancer Screening Rates Low Because of 'Ostrich Effect'?

Kristin Jenkins

January 04, 2018

US Preventive Services Task Force (USPSTF) guidelines currently recommend that cigarette smokers aged 55 to 80 years have annual low-dose computed tomography (LDCT) screening for lung cancer.

The guidelines, based on findings from the National Lung Screening Trial (NLST), also recommend annual screening for former smokers who have quit within the past 15 years but have a 30-pack-year smoking history.

And yet, lung cancer screening rates remain extremely low (3.3% to 3.9%), even after publication of the USPSTF guidelines in 2010 and in 2015, a recent study shows.

Blame it on the "ostrich effect," suggests an expert in health belief model theory, Martin C.S. Wong, MBChB, MD, MPH, from the Faculty of Medicine, Chinese University of Hong Kong, China.

Writing in a letter to editor published online on December 8, 2017, in JAMA Oncology, Dr Wong says studies of health beliefs show that sometimes, frightened patients just want to stick their heads in the sand and make it all go away.

In one population-based survey looking at factors associated with colorectal cancer (CRC), for instance, a group of gastroenterologists and sociologists who examined the factors associated with screening uptake found that patients who thought they had cancer were 72% less likely to undergo CRC screening. Why? Because they didn't want to face the adverse consequences. The researchers attributed this behavior to the "ostrich effect," explains Dr Wong.

"Smokers may face similar psychological barriers when told to undergo LDCT because they might be less interested in and more apprehensive about periodic health examinations," he says.

The CRC study also showed that a family physician's recommendation increased the likelihood of individuals undergoing CRC screening by 23-fold. However, a 2015 survey of family physicians in South Carolina revealed that most had incorrect knowledge about LDCT screening and limited referrals of patients.

"As family physicians can influence screening uptake, issues related to penetration and educational outreach around LDCT screening to physicians should be examined," Dr Wong suggests.

He also recommends that various health beliefs associated with LDCT screening should be identified and the strongest predictors of screening uptake should be evaluated. Strategies that could successfully reduce psychological barriers should also be identified.

Using Risk Rather Than Cutoff Criteria

Separately, a new study suggests that 5000 more deaths from lung cancer could have been avoided in 2015 if risk-based criteria rather than cutoff-based USPSTF recommendations were used to select patients for LDCT screening, say Li C. Cheung, PhD, from the National Cancer Institute, National Institutes of Health, Bethesda, Maryland, and colleagues.

This study was published online January 2 in Annals of Internal Medicine.

In the same issue, another study showed that risk-based CT screening may improve screening efficiency but was less efficient than USPSTF criteria in terms of cost and quality-adjusted life-years, say Vaibhav Kumar, MD, from Tufts Medical Center, Boston, Massachusetts, and colleagues.

In an accompanying editorial, Angela K. Green, MD, and Peter Bach, MD, from Memorial Sloan Kettering Cancer Center in New York City, call the extremely low rate of lung cancer screening a "more pressing concern" than figuring out screening criteria. They suggest that "determining exactly who should be screened may be only academic currently."

In their own analysis of commercial insurance and Medicare Advantage claims data from early 2017, they discovered that of nearly 7 million people who were eligible for lung cancer screening in the United States, only 1% to 2% actually underwent LDCT. The reasons for this very low rate of screening are not clear, they comment.

"Lung cancer remains the most deadly type of cancer in the United States, and low-dose CT screening offers a potentially effective means to improve on that fact," Dr Green and Dr Bach write. "Although risk-based identification of persons who should be offered screening is empirically superior to using the current cutoffs, the more pressing concern is why people, regardless of how their eligibility is defined, are not receiving the test."

Refined risk stratification has the potential to identify more candidates for screening, but in reality, "it is simply a refinement of cutoff-based identification," they add.

Many Clinicians Remain Skeptical

Many clinicians may still be skeptical about the value of LDCT screening, the editorialists suggest, calling the pace at which lung cancer screening is being adopted "anemic."

Four years ago, the USPSTF and the Centers for Medicare & Medicaid Services published guidelines favorable to a risk-stratification approach. However, these endorsements were tepid, and the approach was given low marks, Dr Green and Dr  Bach say.

Since then, several small randomized trials have failed to find a benefit of CT screening for lung cancer, and after 10 years of follow-up, the large randomized Dutch-Belgian lung cancer screening NELSON trial has still not been published, they point out.

Both studies were funded by the National Institutes of Health/National Cancer Institute. Disclosures for Dr Cheung and colleagues can be viewed online. Dr Kumar has disclosed no relevant financial relationships, although several study coauthors report relationships with industry. Disclosures for the editorialists can be viewed online. Dr Wong has disclosed no relevant financial relationships.

JAMA Oncol. Published online December 28, 2017. Letter to editor

Ann Intern Med. Published online January 2, 2018. Cheung et al study, Kumar et al study, Editorial

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