'Life Gain' Approach to Lung Cancer Screening Boosts Benefit

Liam Davenport

October 21, 2019

Selecting individuals for lung cancer screening based on their expected gain in life expectancy could help maximize the benefits and minimize the harms to patients, say researchers reporting a new modeling study.

Li C. Cheung, PhD, and colleagues from the division of cancer epidemiology and genetics at the National Cancer Institute, Bethesda, Maryland, looked at data on over 130,000 "ever smokers" who took part in a US national health survey.

They developed a mathematical model based on prior trial results, and found that balancing an individual's lung cancer risk against his or her potential for life gain from screening resulted in the selection of a younger population that would be missed by other approaches.

Currently, candidates for lung cancer screening are selected by risk, mainly on the basis of their cigarette smoking history. However, such a selection process based on risk "would preferentially include older, heavy smokers with multiple comorbidities who have shorter life expectancy and, consequently, less life gained from screening," the team points out.

In their model, they added an individualized prediction model for overall mortality and life expectancy.

When they compared the two approaches, they found that the individuals picked out by their "life-gain strategy" had a lower average 5-year risk of lung cancer death, at 1.16% vs 1.93% for the risk-based strategy.

However, they had a much greater gain in life expectancy per lung cancer death averted, at 21.7 vs 8.9 years.

They were also younger, at a mean age of 59.5 years vs 75.0 years, were more likely to current smokers, at 76.7% vs 20.8%, and had fewer comorbidities, at an average of 0.75 vs 3.7 for the risk based strategy.

Using such a life-gain strategy instead of the current risk-based strategy would markedly improve the total life expectancy gained from computed tomography (CT) screening for lung cancer, the team concludes.

The research was published online today in the Annals of Internal Medicine.

The authors say their results "have public health implications."

"Our life-gained–based framework could aid in the development of lung cancer screening guidelines such that benefits are maximized; harms are minimized; and the number of prevented deaths, effectiveness, and efficiency are maintained at high levels," the authors claim.

Cheung told Medscape Medical News said that the "numbers of people referred to screening under life-gained–based or risk-based strategies would largely depend on the thresholds for referral."

However, the life-gained approach "can identify moderately high-risk individuals for whom screening could greatly extend life expectancy but may otherwise be missed by both the current approach and risk-based screening" and so "will refer more ever-smokers who are both at high risk and have high life-expectancy," Cheung said.

Cheung believes that the principle of the life-gain approach also could be applied to the screening of other cancers.

"In particular, the age at which to stop screening for cancer depends strongly on an individual's life expectancy," and therefore it "naturally obviates the need to define an upper age to curtail cancer screening," he said.

Instead, using their model based on the life-gain approach, "as long as an individual could gain sufficient life-years from screening, she/he would continue screening," he added.

In an accompanying editorial, Tanner J. Caverly, MD, MPH, and Rafael Meza, PhD, from University of Michigan in Ann Arbor, underline that the life-gain approach is not opposed to risk-based screening but adds "a new step."

"This increases complexity but aligns with goals that all clinicians strive to achieve," Caverly and Meza write.

However, the "added accuracy of screening using a risk-based or life-gained–based approach requires inputs and calculations that might still be challenging to implement for many healthcare systems."

Caverly told Medscape Medical News that this gets at "one of the barriers for people when they think about" CT-based screening for lung cancer: that it is "too complex to implement."

"One of the points I wanted to make is that it's no longer very complex in a lot of health systems to implement this approach. In fact, it can be automated," Caverly emphasized.

He gave the examples of the Veterans Affairs health system, Kaiser Permanente, or "a large academic health system," where "you have a little bit more resources to do a calculation" of an individual's risk and their life expectancy.

Caverly said that the real change is "in thinking about how you select patients for an intervention."

He explained: "I think once clinicians understand intuitively that lung cancer risk is the key here, and the other key is understanding how healthy the person is, their life expectancy…[then] it's no longer complex to implement."

The research was funded by the Intramural Research Program of the National Cancer Institute, National Institutes of Health. Cheung reports that he previously coauthored a manuscript proposing the Lung Cancer Death Risk Assessment Tool model. Coauthor Christine D. Berg, MD, reports consultancies for GRAIL and Medial EarlySign and reports that she is the chair of the Policy Task Group of the American Cancer Society National Lung Cancer Roundtable. The other coauthors have disclosed no relevant financial relationships. Caverly reports grants from Genentech Corporate Scientific Giving Program outside the submitted work. Meza has disclosed no relevant financial relationships.

Ann Intern Med. Published online October 21, 2019. Abstract, Editorial

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