With President Barack Obama pushing his Precision Medicine Initiative, and a slew of new genetic diagnostic tests entering the market, it's worth revisiting the recent payment history for PET scans, the go-go imaging technology whose use exploded in the early 2000s.
Positron emission tomography maps hot spots inside the body by injecting radioactive tracers into the blood that attach themselves to hyperactive cells. Different isotopes used in the scans attach to different cells and are able to cross different internal barriers. It is a form of diagnostic-imaging targeting that parallels the tumor-specific drug targeting of precision medicine.
The attraction of PET, as opposed to regular CT or MRI scans, is its ability to identify diseases such as cancer or Alzheimer's disease early on, or to track their spread in hard-to-see places. However, hard clinical-trial evidence that its use improves outcomes for patients is lacking.
Despite that absence of evidence, over the past decade, the CMS, with private insurers in tow, has approved coverage for PET scans. However, Medicare has tied approval to evidence development, which requires suppliers and physician groups backing the technology to prove that it is actually useful in treating or managing disease.
It's not a cheap technology. A PET installation can cost up to $2 million or more. But with payment at $1,000 a scan, even with the restrictions, the technology has become quite common at community hospitals, many of which now advertise its availability for use with cancer patients.
Last week, though, Medicare proposed withdrawing coverage for one type of PET scan used to monitor cancers that have metastasized to surrounding bones, which most commonly happens in metastatic breast and prostate cancer. The withdrawal—a rarity—was the second setback for this particular technology. The CMS made a similar decision in 2013 for PET's use in identifying early onset of Alzheimer's disease.
In last week's ruling, which goes into effect near year-end, the CMS cited its 2010 decision to pay for coverage, which required companies and the physicians who use it to produce evidence that it improves outcomes. Five years later, the studies remain incomplete.
The agency said it would pay for any uses in ongoing studies for another year, but unless evidence appeared in a peer-reviewed journal documenting that using this form of PET—it uses a sodium fluoride isotope as the tracer— actually improved patient outcomes, it would stop Medicare coverage entirely.
“Studies have been underway since this (coverage with evidence development) decision was posted over five years ago,” the CMS decision memo said. “We are perplexed why additional analyses were not performed and published to confirm actual changes in patient management that improved health outcomes occurred.”
This particular use of PET isn't the only one under siege. Insurers are scrambling to limit the use of PET and other advanced imaging technologies for screening patients every three months after cancer treatment, even when there are no symptoms that the disease has recurred. Some insurers limit scans to two per patient; others require prior authorization.
It's not only insurers questioning the technology. The American Society of Clinical Oncology has put excessive use of PET, along with other expensive diagnostic imaging tests, such as CT and MRI tests, on its “Choosing Wisely” list of technologies to consider carefully before deploying. ASCO now recommends against using imaging tests for low-risk, early stage breast cancer and prostate cancer.
Given the potential for overtreatment because of false positives associated with any imaging test, and the significant doses of radiation absorbed with each scan, “the risks of imaging far outweigh any potential benefit,” the physician group warned.
The CMS stance on PET is an artifact of fee-for-service medicine. In a few years, as insurers in both the public and private sectors gravitate toward episode-based and bundled care, the risk of using expensive and unproven technologies that don't improve outcomes won't fall on payers. It will fall on the purchasers of those expensive technologies which, for PET scanners, are mostly hospitals.
Going forward, it won't just be the government that will need to ask hard questions about the medical evidence justifying large investments in advanced technologies.