System May Spot Silent Killer
EVANSTON, Ill., Aug. 2, 2007 -- New optical technology shown to be effective in the early detection of colon cancer now appears promising for detecting pancreatic cancer, the fourth most common cause of cancer deaths in the US.
Known as a silent killer, pancreatic cancer spreads rapidly and seldom is detected in its early stages, which is the primary reason it killed more than 33,000 Americans last year. The pancreas also can become dangerously inflamed if examined directly, so routine inspections for at-risk patients are not usually an option.
Vadim Backman (right) of Northwestern University and Hemant Roy of Evanston-Northwestern Healthcare demonstrate a portable version of the new spectroscopy tool that is showing promise with colon cancer detection. The researchers are now working on developing a portable version of the system to aid with pancreatic cancer detection. (Image: Northwestern University, Evanston-Northwestern Healthcare)
The extraordinarily sensitive new technique, which is minimally invasive and takes advantage of certain light-scattering effects, can detect abnormal changes in cells lining the duodenum (part of the small intestine) even though the cells appear normal when examined with a conventional microscope. The techniques produce an optic fingerprint from the altered tissue and then enhance the data for a clearer diagnosis.
The technique could lead to the first screening method for pancreatic cancer in asymptomatic patients, said Vadim Backman, developer of the technology and professor of biomedical engineering at Northwestern University's Robert R. McCormick School of Engineering and Applied Science.
Backman and Yang Liu, a former graduate student of Backman’s, teamed with physicians at Evanston Northwestern Healthcare (ENH) to test the technique in a pilot study of 51 patients. The researchers found they could detect both early- and advanced-stage pancreatic cancer without touching or imaging the pancreas.
The results build upon prior studies with colon cancer and support the "field effect" hypothesis that suggests initial cancer stages, even precancerous lesions, can cause minute, potentially detectable changes throughout an entire organ. If similar results are found in other organs, the effect could have broad impact in the timely treatment of breast cancer, lung cancer and others.
Pancreatic cancer, unseen at its earliest stages by any other method, can be detected by examining tissue from inside the duodenum, the uppermost section of the small intestine. The pancreatic duct communicates with the duodenum via the Ampulla of Vater. Researchers have shown that cells in a roughly 3-cm radius from this feature can show signs of the presence of cancer. (Image: Zina Deretsky, National Science Foundation)
"This novel technology uses light to probe tissue architecture at submicron scale. We are excited about this technology because it enables sensing subtle changes in tissue that otherwise are undetectable by conventional microscopic examination," said Backman, a co-author of a paper on the research.
By studying tissue extracted from an area adjacent to the pancreas, the researchers were able to screen all 51 patients with little risk of inflammation or other complications. While clinical use is perhaps three to five years in the future, and ongoing studies are needed to confirm the results, the researchers hope the tests can eventually be done without the biopsy.
"We were so encouraged by the successes with colon cancer that we decided to drive the research in a new direction. With colon cancer, you have time, even years, to treat it successfully. Unfortunately, for pancreatic cancer it's not only critical to detect it early, or even before it becomes cancerous, but in many cases it is really the only hope," said Leon Esterowitz, the National Science Foundation (NSF) program officer who has been supporting the research.
The next stages of the research trials incorporate some examinations that are biopsy-free and use a shoebox-sized fiber-optic version of the new system, a device now being tested during colonoscopies.
Researchers can look at how light bounces off of human tissue to detect subtle changes potentially caused by cancer. The spectral image that results is like a fingerprint for disease. The technology was developed by researchers at Northwestern University and colleagues at Evanston-Northwestern Healthcare. (Image: Nicolle Rager Fuller, National Science Foundation)
"Besides improving on the technology, we need to determine whether other medical conditions including other cancer types or diseases of the pancreas such as chronic pancreatitis or acute pancreatitis can be distinguished with our technology from pancreatic cancer. It is also important for us to validate our prediction rule on a larger number of pancreatic cancer cases as well as different control groups." said co-author Randall Brand, a gastroenterologist from ENH and an expert on pancreatic cancer.
In trials that began before the pancreas research, the researchers saw encouraging results with colon cancer detection in a study of 500 patients. The new approach also predicted, with 100 percent accuracy, polyps in patients diagnosed with a simultaneous colonoscopy.
Because the experimental procedure only scans the outer few centimeters of the colon and does not require the uncomfortable cleansing process required for a colonoscopy, the researchers believe the approach will encourage more people to get screened before they develop symptoms of disease.
The portable system was not used in the pancreatic cancer studies because the probe needs to be modified for the different scope used in endoscopy, but the underlying technology behind all of the examinations is the same. Each patient was scanned using a combination of elastic light-scattering and low-coherence enhanced backscattering techniques developed by Backman and his colleagues over the last five years. The researchers developed the four-dimensional elastic light-scattering fingerprinting (4D-ELF) and low-coherence enhanced backscattering spectroscopy (LEBS) systems.
The combined four-dimensional elastic light-scattering fingerprinting (4D-ELF) and low-coherence enhanced backscattering spectroscopy (LEBS) technologies were developed by Vadim Backman and his colleagues at Northwestern University. (Image: Northwestern University, Evanston-Northwestern Healthcare)
Whether in a laboratory or in the portable, fiber-optic system, a xenon lamp shines intense, white light through a series of lenses and filters onto the specimen. The light refracts through the outermost layer of tissues and scatters into a spectrograph, a device that separates a beam of white light into its component wavelengths and measures them. An image sensor captures the result for analysis by a computer.
The technological breakthrough is the ability to cause light to penetrate the cells most affected by cancer without hitting deeper unaffected cells and to scan cell structures on the scale of nanometers, smaller than a doctor can see with a microscope.
"Contemporary diagnostic medicine frequently relies on invasive procedures, such as endoscopy, to detect disease. In the fictional world of 'Star Trek,' a doctor is able to make a diagnosis without ever interrogating an organ. Biophotonics shows that this approach may be closer to reality that one might expect," added Backman.
The nanoscale approach allows the researchers to differentiate cancerous or precancerous tissue from normal tissue, even if the specimens look identical under a normal biopsy. In both studies, the techniques worked regardless of age, tumor size, smoking history or tumor location, although the researchers hope to use the next trial phase to test individuals with serious pancreatic diseases that are not cancer to see if the changes are truly unique to cancer. Eventually, the researchers hope to expand their study to breast cancer, lung cancer and other variations of the disease.
While the new techniques must undergo further study before its effectiveness can be confirmed, the researchers have partnered with American BioOptics to fully develop the technology. In July, American BioOptics received an NSF Small Business Innovation Research grant to further develop the technology for colon cancer screening and ready the system for commercialization.
The pancreatic cancer study was supported by NSF and the National Institutes of Health.
The findings are reported in the Aug. 1 issue of the journal Clinical Cancer Research. Additional co-authors on the paper include Vladimir Turzhitsky and Young Kim of Northwestern University and Hemant Roy, Nahla Hasabou, Charles Sturgis, Dhiren Shah and Curtis Hallof Evanston-Northwestern Healthcare.
For more information, visit: www.northwestern.edu
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