Medicare bucks USPSTF, denies coverage for lung cancer screening

The Centers for Medcare and Medcaid Services sent lung cancer screening's forward momentum into a tailspin last month, when Medicare's advisory panel shocked observers by voting  against covering lung cancer screening with annual low dose chest CT as a standard benefit.

The U.S. Preventive Services Task Force (USPSTF) had already recommended lung cancer screening be included in standard preventive services for current and former heavy smokers, and the Affordable Care Act stipulates that such services be provided for free to patients with private insurance. But Medicare sets its own rules, and in this case took a decidedly contrarian stance to the USPSTF's. The federal government's disagreement with itself sets the stage for a confusing two-tier system for patients according to public vs. private insurance status, and will be seen by many as an example of rationing of an expensive service in an increasingly cost conscious era.

The Center for Medicare and Medicaid Services (CMS) panel cited its concerns about the high false positive rate of abnormal lung cancer screening tests (96%), likely extension of screening into lower risk populations (increasing risk and reducing benefits), and quality control issues in the community (ensuring low radiation doses and good follow-up care).

Lack of generalizability of NLST to the older eligible population was another major concern. More than half of people diagnosed with lung cancer are older than 70, and 80% are older than 60. But only 1/4 of the National Lung Screening Trial were older than 65 (and none older than 74). By this argument, the real-world benefits and risks of lung cancer screening were poorly tested by NLST and remain unknown.

One panelist pointed out that CMS currently spends $1 billion annually on colon cancer screening for octogenarians, despite admonitions to community physicians not to screen this group. Another pointed out that using self-reported pack-year smoking history as the main criterion will lead to worried-but-low-risk patients exaggerating their smoking histories. Another warned of "unrestrained entrepreneurialism" leading to "an explosion of inappropriate activities" should Medicare cover lung cancer screening. (We've already seen the first wave of that, with $99 chest CT scans advertised as loss-leaders for patient-hungry medical centers.)

Meanwhile, a respected new study estimates that lung cancer screening will cost $2 billion to Medicare annually, increasing premiums by $3/month. By comparison, mammography is estimated to add $2.50 to monthly premiums and colon cancer screening, about $1. The study will be reported at the American Society of Clinical Oncology later this month.

Most of this cost is due to the high false positive rate of lung cancer screening, resulting in a lot of wasted dollars, time, fear, etc. Even in the NLST enrollees, all of whom had heavy smoking histories, only 40% of the patients were at particularly high risk and gained the lion's share of benefit of screening. (Conversely, the lower-risk quintiles had very low benefits from screening.) As epidemiologists and biomedical engineers devise more nuanced and clever ways to predict lung cancer risk in smokers, it's likely that all public and private insurance would cover lung cancer screening in the truly high risk subgroups of people with heavy smoking histories.

Lung cancer experts were predictably disappointed by the decision. Don't count out the court of public opinion and political pressure as a lever to reverse Medicare's decision before its "final answer" in 2015 -- although lung cancer hasn't ever gotten much traction in the billion dollar cancer advocacy game.