June 1, 2000 -- A whole new generation of tests to diagnose disease is on the horizon. Some laboratory tests and imaging studies may even cost less than current alternatives, making early cancer detection a reality more often.
In response to consumer demand for cancer screening, imaging centers in Southern California are offering full-body CT scans (pronounced 'cat' scans and similar to an X-ray) for healthy people. "Most full-body scans just identify scar tissue and [noncancerous] growths, but invasive follow-up tests are often needed to rule out serious disease, says Deborah Baumgarten, MD, an associate professor of radiology at Emory University School of Medicine in Atlanta.
Full-body CT scans are not covered by managed care health plans, but new laboratory tests may soon be. As a low cost-screening tool, detection of genetic mutations holds promise for many cancers and requires just a few drops of blood, urine, and saliva. "In five years, [these] tests will be routine for common cancers," says co-developer David Sidransky, MD, professor of oncology and otolaryngology at Johns Hopkins University School of Medicine in Baltimore.
In diagnosing cancer, Sidransky tells WebMD that these new tests won't replace traditional testing, but will probably serve as a first step. A urine test for bladder cancer could be available within the next two years. Soon after, blood and saliva tests for lung, breast, prostate, and colon cancers will be available at a cost of about $200.
Until then, new approaches in bowel imaging are less invasive than traditional exams. Virtual colonoscopy allows doctors to see inside the colon without a scope inserted into the rectum. "Computer software turns a simple CT scan into a fantastic voyage of the colon," says Joseph Ferucci, MD, chairman of radiology at Boston Medical Center and professor of radiology at Boston University School of Medicine.
Virtual colonoscopy eliminates the risk of penetrating the bowel wall with the instruments and the need for sedation, but won't replace traditional colonoscopy for everyone. "If large pre-cancerous polyps are found, they'll have to be snared with a colonoscope," Ferucci tells WebMD. "But for most people, the virtual procedure is two thirds the cost of traditional colonoscopy and will ultimately be the price of a mammogram."
Another approach to imaging of the digestive track is as simple as swallowing a capsule. Researchers in the U.K. and Israel have developed a wireless video camera that transmits images, of the stomach and intestines, as it moves though the digestive tract. "It's a gulpable minicam," says Sandra Ziv, the marketing manager at Given Imaging in Yogneam in Israel. "The capsules shoot an eight-hour movie, then computer software turns it into a 20-minute film clip."
The video capsules are not likely to replace gastroscopy and endoscopy, in which a long flexible scope is passed through the throat. "Capsules have fewer risks and don't require sedation, but traditional procedures will still be needed to treat digestive disorders," adds Ziv. "For diagnosing problems, the cost will be about the same and patients can continue their daily activities without interruption." Ziv tells WebMD that the new device could be available later this year.
Computer software also can be used to increase the value of imaging tests. Doctors miss one in four breast cancers with mammograms, but computer-aided diagnosis makes doctors better, according to David Ku, MD, PhD, an assistant professor of surgery at Emory University School of Medicine and professor of mechanical engineering at Georgia Institute of Technology, both in Atlanta.
With Ku's Internet-based application, doctors can compare abnormalities to a growing database of digital mammograms, providing a virtual second opinion. In addition to early cancer detection, Ku believes computer-aided diagnosis will reduce the number of false positive readings, resulting in fewer breast biopsies. The makers plan to launch the program in January.
Intelligent computers also may provide an alternative to the arteriogram, where a small tube is fed through the groin to view blood vessels of the heart and neck. "A traditional MRI scan [similar to an x-ray] overestimates blockage, but artificial intelligence makes it as accurate as an arteriogram, without all the risks," says Harris Bergman, PhD, a biomedical engineer and co-founder of Atlanta-based MediZeus. "Bergman tells WebMD that the MRAngiogram will be available in about three years at one quarter the cost of the traditional method.
- Researchers say over the next few years, a new generation of laboratory tests and imaging techniques will become available to help doctors screen patients for disease. The advances promise to be less invasive and may even be cheaper than current procedures.
- Computers and data bases may even help doctors analyze test results so fewer patients with diseases are missed.
- The new techniques will supply physicians with different initial tests to diagnose disease before they have to resort to the standard tests that are used today.