Cancer diagnosis: Microscopy technique identifies early stage lung cancer via cheek swab
Evanston, IL--Researchers from Northwestern University and NorthShore University HealthSystem (NorthShore) have developed a method to detect early signs of cancer by examining cheek cells in humans using biophotonics technology. "By examining the lining of the cheek with this optical technology, we have the potential to prescreen patients at high risk for lung cancer, such as those who smoke, and identify the individuals who would likely benefit from more invasive and expensive tests versus those who don’t need additional tests," said Hemant K. Roy, M.D., director of gastroenterology research at NorthShore.
The technique is among a growing number of optical cancer detection methods and is called partial wave spectroscopic (PWS) microscopy and was developed by Vadim Backman, professor of biomedical engineering at Northwestern’s McCormick School of Engineering and Applied Science. Backman and Roy earlier used PWS to assess the risk of colon and pancreatic cancers, also with promising results.
The lung cancer findings are published (online October 5; in print October 15) by the journal Cancer Research in a paper entitled "Optical Detection of Buccal Epithelial Nanoarchitectural Alterations in Patients Harboring Lung Cancer: Implications for Screening."
Lung cancer is the leading cause of cancer deaths in the United States. Survival rates are high with surgical resection (removal of the tumor) but only if detected at an early stage. Currently there are no recommended tests for large population screening to detect lung cancer early. The disease is already advanced by the time most lung cancer patients develop symptoms. The five-year survival rate for lung cancer patients is only 15%.
PWS can detect cell features as small as 20 nm, uncovering differences in cells that appear normal using standard microscopy techniques. The PWS-based test makes use of the "field effect," a biological phenomenon in which cells located some distance from the malignant or pre-malignant tumor undergo molecular and other changes.
In a study, 135 participants including 63 smokers with lung cancer and control groups of 37 smokers with chronic obstructive pulmonary disease (COPD), 13 smokers without COPD and 22 non-smokers, were analyzed. The researchers swabbed the inside of patients’ mouths, and then the cheek cells were applied to a slide, fixed in ethanol and optically scanned using PWS to measure the disorder strength of cell nanoarchitecture. Results were markedly elevated (greater than 50%) in patients with lung cancer compared to cancer-free smokers. A further assessment of the performance characteristics of the "disorder strength" (as a biomarker) showed greater than 80% accuracy in discriminating cancer patients from individuals in the three control groups.
"The results are similar to other successful cancer screening techniques, such as the pap smear," Backman said. "Our goal is to develop a technique that can improve the detection of other cancers in order to provide early treatments, much as the pap smear has drastically improved survival rates for cervical cancer." Additional large-scale validation trials are necessary for PWS.
SOURCE: Northwestern University; www.northwestern.edu/newscenter/stories/2010/10/lung-cancer-detection.html
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Gail Overton | Senior Editor (2004-2020)
Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.