The utility and value of low-dose computed tomography (LDCT) annual lung cancer screening for high-risk patients remains controversial, even though the 2011 results of the National Lung Screening Trial (NLST) demonstrated that screening could substantially reduce mortality through early detection. The benefit of preventing three lung cancer deaths per 1,000 persons screened is offset by high false-positive rates, potentially triggering additional diagnostic tests, clinical procedures, anxiety, and expense to both patients and the healthcare system.1 Additionally, research has shown that absolute risk reduction varies greatly among at-risk individuals.2
Researchers from the VA Center for Clinical Management Research and University of Michigan Medical School in Ann Arbor developed a complex microsimulation model to examine the effect of patient preferences on the net benefit of screening. The National Health Interview Survey (NHIS) was used to simulate a nationally representative sample of 1 million persons aged 55 to 80 who met the U.S. Preventive Services Task Force (USPSTF) criteria for heavy smoking. The authors describe the model in detail and report the circumstances in which patient preferences can be clinically in the Annals of Internal Medicine published online May 29. They also provide recommendations for personalizing LDCT screening discussions based on estimating annual lung cancer risk.
The microsimulation modeling analysis directly addressed the question: When is screening necessary for the health of a patient and when can patient preferences to avoid screening be considered valid? In addition to patient demographics and clinical history, the model incorporated “disutilities” and degrees of dislike, quantifying such features as negative feelings about LDCT screening, direct costs to patients, screening outcomes, and recommended follow-up tests and treatment. Besides analyzing how quality-of-life year (QOLY) gains varied across a range of disutilities for a large, diversified population of LDCT-eligible patients, the researchers also examined the effect of varying the rates of false-positive results and overdiagnosis associated with LDCT screening.
The researchers determined that the clinical benefit and QOLY gains provided by annual screening depended on a patient’s life expectancy and annual risk for lung cancer. Lead author Tanner J. Caverly, MD, and colleagues reported that for the approximately 53% of patients with a life expectancy of more than 11 years and a high annual lung cancer risk greater than 0.3%, preferences against screening would diminish potential benefits of catching an early cancer, but would not necessarily provide such superior health benefits that it should be a clinical necessity. And for patients with a life expectancy less than 11 years and low annual cancer risk, screening benefits were negligible and could even lead to harm. The authors wrote that “the large absolute mortality benefit of LDCT screening among high-risks patients translates into substantial QOLY gains only when the patient also has a long life expectancy.”
Highly influential factors with respect to annual screenings and health and QOLY gains were risk for lung cancer, competing health risks, estimated life expectancy based on age and other co-morbidities, and patient preference. In general, about 50% of the high-risk population would benefit from screening regardless of whether they preferred not to have the exam. Of particular interest was that false-positive rates between 10% and 60% had little impact on the model’s results.
The authors suggest that physicians evaluate the risks and benefits of LDCT lung cancer screening on a case-by-case basis They encourage using a screening decision support tool, and have created one that is based on the microsimulation analysis. Available in English and Spanish and designed for patient as well as physician use, it can be freely accessed at www.shouldiscreen.com.
Patient preference impact on LDCT lung cancer screening. Appl Radiol.