Whole-body CT screening slumps after fast start

June 12, 2002

Even Oprah can't guarantee sustained demandPumped up by publicity from Oprah Winfrey's television talk show over a year ago, whole-body CT screening experienced a burst of business activity and demand by customers willing to

Even Oprah can't guarantee sustained demand

Pumped up by publicity from Oprah Winfrey's television talk show over a year ago, whole-body CT screening experienced a burst of business activity and demand by customers willing to self-refer and pay the bill. CT screening centers popped up nationwide, but public demand has slacked off, leaving many in a precarious financial position.

"Because of the Oprah show, the public began demanding whole-body CT screening, so a whole bunch of centers using spiral scanners opened up," said Douglas P. Boyd, chief scientist at GE Imatron. "Now we are in a negative phase. A lot of those centers are going bankrupt and closing. They are cutting prices."

The market for whole-body screening with CT is likely to remain on a downswing until scientific research catches up to the technology, Boyd said. In the meantime, some CT screening applications that have more solid research support are likely to grow. These include cardiac as well as lung and colon cancer screening.

Boyd is the former chair and founder of Imatron, which was purchased by GE Medical Systems last year. He developed Imatron's electron-beam tomography scanning technology while on the faculty at the University of California, San Francisco.

Prior to being purchased by GE, Imatron sold off its HeartScan cardiac screening business. As the supplier of EBT systems to HeartScan, however, Imatron maintains a strong connection. HeartScan has expanded into noncardiac screening applications, including whole-body screening.

When Imatron first introduced heart screening using its EBT system, it did so after many papers had already been published on the subject, Boyd said. Body scanning started off in a similarly measured fashion, but then it was propelled ahead by the favorable publicity.

"They jumped the gun. Whole-body CT screening got ahead of itself," he said.

While clinicians were questioning the lack of long-term outcome studies of whole-body CT screening, the FDA came out with a statement last year warning of high radiation doses being applied in CT screening applications. Publicity in the general press about this concern helped dampen demand, Boyd said.

Multicenter clinical trials studying low-dose CT lung screening will look for whether cancers can be found that otherwise would not be and, more important, whether this has an impact on mortality from lung cancer, according to Dr. Ron Castellino, chief medical officer for R2 Technology. Castellino is a retired radiologist who formerly headed departments at both Stanford University and Memorial Sloan-Kettering Cancer Center.

"With lung cancer, unfortunately, people have a tendency to die relatively quickly," he said.

R2 is one company that could benefit from the expansion of CT lung screening, since it is developing a CT application of its

computer-aided tumor detection software. The firm remains neutral in the CT screening debate, however. Compared with the potential use of computer-aided detection technology in finding lung nodules through the analysis of all diagnostic spiral CT chest scans, CT lung screening is a small niche, Castellino said.

"When you look at the panoply of reasons why scans are done, currently maybe 1% or less of the CT scans in this country are for lung cancer screening," he said.

Since CT lung cancer screening is performed largely on high-risk patients, particularly smokers, it tends to have a high yield of cancers detected, according to Boyd.

"We know that about 10% of smokers will have lung nodules, and somewhere between 10% and 20% of those nodules will be malignant," he said. "So the yield is pretty good, about 2% malignant. These are small, treatable nodules."

The high yield of CT screening in detecting heart problems as well as lung and colon cancers is a major reason why these applications face better prospects than whole-body screening, Boyd said. Yields are low in whole-body screening both because it is hard to pick out a high-risk group to screen and because many of the cancers found are much rarer than lung cancer. This lower chance of detecting problems then has to be weighed against the risks encountered by patients in the healthcare system.

"When you have a screening test with a low yield, a low percentage of the patients that have it are going to have a positive finding, and there is a higher probability that the risk/benefit ratio won't be positive," Boyd said.