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UW study: low-dose CT scans for lung cancer too costly?

by February 15th, 2012

A new study from University of Washington and Fred Hutchinson Cancer Research Center experts in Seattle finds that the overall costs of detecting and treating lung cancer among heavy smokers through a potentially promising process involving screening with low-dose CT scans may currently be too costly to a nation struggling to control growing health care costs, even though some lives would be saved. They urge development of cost-effectiveness standards to guide further policy-making, and emphasize that costs can be cut if health care providers improve their diagnostic skills to more frequently sidestep “false positive” results of the scans.

Concerns about radiation from CT scans
Computed tomography or CT scans, give a transparent view of the body and have been used to help detect colon polyps, conditions of the heart and brain, and for angiograms. But the scans can have a high dose of radiation which may put patients at some degree of added risk for cancer.

Low-dose CT scans emerge
In response, low-dose CT scan technology has been developed as a screening strategy for lung cancer and a National Cancer Institute screening trial found its use among heavy smokers achieved a 20 percent relative decrease in lung cancer deaths.

A way forward in lung cancer diagnosis?
The authors of the new UW/Fred Hutch study, published in the February edition of the Journal of the National Comprehensive Cancer Network, note that those national trial results “sparked intense debate….about..implementing LDCT (low-dose CT scan) screening nationwide. The main concerns include the financial burden that a national LDCT screening program would impose on the U.S. health care system, which currently struggles to contain escalating expenditures, and the patient burden that results from a high false-positive screening rate…including unnecessary costs and harms caused by additional imaging tests and surgical procedures.”

Modeling costs and benefits
So they set out to develop a ‘budget impact model” to assess the costs and benefits of low-dose CT scan screening of the eligible heavy smoker/former heavy smoker population in the U.S. Drawing on sample criteria from the earlier national screening trials, they focused on those aged 55 to 74 who smoked at least 30 packs of cigarettes per year or had done so within the last 15 years. This is about 10 percent of all smokers. They then applied two variants, the actual at-risk U.S. screening rates of 50 and 75 percent, respectively, for colorectal and breast cancers. Using current data on false-positive rates and costs of additional procedures after initial positive diagnoses of lung cancer, they developed their model. A key consideration from the scientific literature, factored into their model, was that 320 patients have to be screened for lung cancer with low-dose CT scans for one lung cancer death to be avoided.

Results of running the model
The authors reported that the results of applying their model were eye-opening. At the 50 percent screening rate of the eligible population, 1.7 million people would be screened and more than 486,000 would be found by the initial low-dose CT scan to have a positive screening test, or a lung nodule greater than 4 mm, prompting further confirmatory testing. However all but just more than 17,500 of those 486,000 so-called “positives” would upon further diagnosis and treatment turn out to be “false positives.” The total costs of screening and follow-up procedures would be $1.3 billion per year and 5,428 lives would be saved annually, from the low-dose CT scans for early-stage lung cancer. The cost would be $240,081 per lung cancer death avoided.

At the 75 percent screening rate, 2.6 million people would be screened; more than 729,000 would be initially classified as positives; but only 26,000-plus would turn out to be true positives. The costs per year would total $1.9 billion and the cost per lung cancer death avoided would be $242,074.

CDC Report: U.S. Adult Smoking Not Fading Away,” Public Data Ferret

The need for cost-effectiveness standards…
The authors drew several conclusions from running their model. As designed it would increase current U.S. lung cancer-related expenditures 12 to 19 percent and would “impose additional challenges to public and private insurers who struggle to contain the escalating costs of health care.” The cost per life saved of $240,000 needs to be further evaluated, they say, using cost-effectiveness standards that haven’t yet been developed. Expanding the inclusion criteria for low-dose CT screening of lung cancer to slightly less heavy smokers (20 packs per year now or within the last 15 years) “could increase expenditures sharply, with no evidence showing a mortality benefit,” they add.

…and better analysis of results
The authors say that the elephant in the room is the high false positive rate, which may be able to be reduced through more careful analysis of the low-dose CT scans, including better adherence to so-caled “diagnostic algorithms” available for analysis afterward.

Source: Lung Cancer Screening With Computed Tomography: Costs, National Expenditures, and Cost-Effectiveness/Journal of the National Comprehensive Cancer Network

The study was authored by Dr. Bernardo H. L. Goulart of the University of Washington and the Fred Hutchinson Cancer Research Center; Dr. Mark E. Bensink and David G. Mummy MBA, of the FHCRC’s Research and Economic Assessment of Cancer and Healthcare (REACH) group; and Dr. Scott D. Ramsey of the University of Washington and the FHCRC.

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