CBET Award Achievements
Notable Accomplishments from CBET Awards
 

Early Colon Cancer Screening without Colonoscopy

Vadim Backman, Northwestern University

Background:  Contemporary diagnostic medicine frequently relies on invasive procedures, such as endoscopy, to detect disease.  In the fictional world of Star Trek, a physician is able to make a diagnosis without invasive procedures analyzing an organ.  Advances in biophotonics made by the Backman Group at Northwestern University in coordination with industry may bring this fictional technology closer to reality.

The Backman Group with their industrial partner invented and developed a novel optical technology called low-coherence enhanced backscattering (LEBS), which senses subtle changes in tissue nanoarchitecture otherwise undetectable by histopathology.  LEBS can detect alterations in histologically normal-appearing cells due to the presence of precancer in a different part of an organ.  This may lead to dramatic advances in both medicine and cancer research as it may no longer be necessary to interrogate an organ in order to find precancerous tissue.

In particular, the researchers focused on colon cancer.  Colon cancer remains the second leading cause of cancer deaths in the U.S. largely because screening the entire eligible population (about 87 million Americans over age 50) via colonoscopy is practically impossible for reasons including expense (this screening would cost up to $100 billions annually), patient reluctance, and insufficient number of endoscopists.  Instead of performing colonoscopy on the entire population, a noninvasive screening test that identifies who does and does not harbor precancerous colonic lesions would allow selecting patients who can actually benefit from colonoscopy.  The strategy has certain parallels with Pap-smear screening for cervical cancer: 50 years ago, cervical cancer used to be the first major cause of cancer deaths in women.  The incidence was reduced by more than 70% by introduction of the Pap-smear as an initial screening test.  Currently, no such initial screening test is available for colon cancer.

Results:  The Backman Group used LEBS to analyze tissue in the rectum in patients undergoing colonoscopy.  The results of the LEBS analysis were then correlated with the colonoscopic findings such as the presence of precancerous adenomas anywhere in the colon.  Enhanced backscattering is a fascinating light-scattering phenomenon in random media due to the constructive interference of photons traveling time-reversed paths.  LEBS enables depth-resolved spectroscopic analysis of nano and microarchitecture of tissue and is sensitive to changes in tissue organization that are otherwise undetectable by histology.  A key capability of LEBS is that it senses changes in histologically normal-appearing tissue at a distance from a precancerous lesion.  The biological underpinnings are the concept of field-carcinogenesis (aka. field-effect) in the colon.  This opens a possibility to identifying patients harboring adenomas in the colon by assessment of histologically and colonoscopically normal-appearing rectal tissue without the need for colonoscopy or bowel purging.

A study on 200 patients demonstrated that LEBS analysis of rectal tissue had excellent accuracy for the identification of patients harboring precancerous lesions anywhere in the colon with 100% sensitivity and 88% specificity.  No other noninvasive technique allows similar performance with conventional techniques such as fecal occult blood test being less than 10% sensitive.  This result demonstrates that this novel biophotonics technology could be used for colon cancer screening.  The Backman Group is currently extending this methodology to noninvasive screening for other leading cancers including pancreatic, breast and lung cancers.

Vadim Backman Image
 
This image shows an LEBS signal from human rectal tissue.  The signals contain information
about tissue nano/microarchitecture.  Any signal alteration, in otherwise histologically
normal-appearing tissue, is a diagnostic test for the presence of precancer.

Credit:  Bachman, V. and Kim, Y; Northwestern University


Scientific Uniqueness:  The Backman Group reported the phenomenon of LEBS for the first time.  Although enhanced backscattering has previously been studied in non-biological systems, it was extremely difficult to observe this effect in weakly scattering media such as biological tissue.  The Group overcame all major barriers preventing the use of LEBS in biological applications by recording enhanced backscattering under spatially low-coherence illumination.  Furthermore, the Group was the first to combine a biophotonics methodology with the biological concept of the field effect in carcinogenesis.  Finally, the study helped discover that alterations in cell nano and submicron architecture develop extremely early in carcinogenesis.

Impact on Industry and/or Society:  LEBS has the potential to become the population-wide initial screening test for colon cancer.  The inventors formed an enterprise dedicated to bringing this technology to clinical practice.  The Backman Group envisions the use of LEBS fiber-optic probe during an annual rectal exam by a primary care physician to determine the need for colonoscopy.  This test can be performed without the need for colonoscopy or colon preparation.  The latter is one of the major reasons for patientsí non-compliance for colonoscopy.  Based on the results of the LEBS test, a patient may be indicated to undergo a colonoscopy.  Thus, patients at a higher risk for colon cancer will receive colonoscopies as appropriate, whereas low-risk patients will not undergo these expensive and uncomfortable procedures.

Work is notable because the Backman Group discovered a novel physical phenomenon which led to the development of a novel biophotonics technology and to successful clinical studies.  The work is also notable because of its profound societal implications as it has the potential to change current medical practice by allowing accurate population screening for a number of major cancers.

Work involves multidisciplinary research:  The conception and execution of the project was based on close collaboration among biomedical engineers, physicists, biologists, and clinicians.  The project was based on combining recent developments in physics, optics, and cancer biology.

This project addresses the NSF Goals of:  (1) Discovery and (2) LearningThis work is at the forefront of discovering new photonics techniques and their integration with advances in cancer biology with the potential to substantially reduce cancer mortality by early screening for colon and, in the future, other types of cancer.  The project trained graduate, undergraduate and high-school students in a multidisciplinary approach to biomedical problems.

This Nugget represents transformative research.  This novel technology could dramatically reduce cancer mortality by enabling, for the first time, truly population-wide screening for colon cancer and, in the future, other types of cancer including the lung, breast, pancreas, etc.



     
Program Officer:   Leon Esterowitz
     
NSF Award Number:   0620303
     
Award Title:   SGER: Biophotonics Techniques for Accurate Diagnosis of Pancreatic Cancer
     
PI Name:   Vadim Backman
     
Institution Name:   Northwestern University
     
Program Element:   7236
     

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This Nugget was Updated on 28 October 2008.