New Minimally Invasive Sampling Technique Allows for Earlier Diagnosis of Pancreatic Cancer
August 1, 2007
Field(s) of Research
PHILADELPHIA - A new optical technology, coupled with routine endoscopy, may enable doctors to detect the subtle tell-tale traces of early pancreatic cancer, according to researchers at Northwestern University in Illinois. The optical technology, developed by biomedical engineers at Northwestern exposes cellular changes indicative of cancer in tissue near the pancreas that had previously been detectable only through intensive radiologic scanning or invasive surgery, two techniques that can put pancreatic cancer patients at risk.
The results of the pilot study, presented in the August 1 issue of Clinical Cancer Research, a journal of the American Association for Cancer Research, could represent a new approach to detecting pancreatic cancer at a very early stage, when treatment is most likely to succeed.
"Pancreatic cancer is not often detected early because it is a rather inaccessible organ, so this technique holds the potential to be the first reliable, routine screening tool for pancreatic cancer," said co-author Randall Brand, M.D., an associate professor of medicine at Northwestern University and clinician at Evanston Northwestern Healthcare. "If we could apply this to those at high risk - such as people with chronic pancreatitis or who have a family history of pancreatic cancer- we might see a drastic improvement in pancreatic cancer survival."
Pancreatic cancer is one of the leading causes of cancer death in America - over 33,000 Americans will likely die from pancreatic cancer in 2007, according to projections from the American Cancer Society. The five-year survival rate for pancreatic cancer is less than five percent of all cases. However, if caught at an early stage, available treatments cause the five-year survival rate to jump 10-fold to 50 percent, Dr. Brand said.
Although the pancreas is a difficult organ to study, the researchers took advantage of the so-called "field effect" of pancreatic cancer, where cancerous tissue exerts subtle physical changes in surrounding tissue. In an examination of 51 patients using tissue sampled through upper endoscopy (a minimally invasive procedure that entails the placement of an endoscope down the throat and through the stomach to the duodenum), the researchers were able to identify those patients with pancreatic cancer from the control group with a 95 percent accuracy. Importantly, the researchers could identify all 10 patients with early stage tumors that could be removed surgically.
"If we could reliably detect the presence of cancer prior to our ability to visualize it with our current imaging studies such as a CT scan or MRI, we would then have the justification to pursue aggressive surgical options," Dr. Brand said.
The optical technology used to detect the field effect of pancreatic cancer was developed by the senior author of the study Vadim Backman, Ph.D., a professor of biomedical engineering at Northwestern along with his graduate student, Yang Liu, Ph.D, the first author on the report. With a single instrument, Backman can use two different means of detecting the optical properties of a tissue sample, both of which were developed in his laboratory: four-dimensional elastic light scattering fingerprinting (4D-ELF) and low-coherence enhanced backscattering spectroscopy (LEBS).
In essence, the 4D-ELF/LEBS instrument shines an intense white light onto a tissue sample and then measures how cellular structures on the micro- or nanoscale (on the order of a billionth of a meter) refract the light, causing it to scatter in different directions. Computer analysis of the scatter patterns can then determine if these cellular structures are different than those seen in structures within "normal" tissue. The researchers looked for the same optical changes that had been identified in a colorectal cancer study by Backman and Hemant Roy, M.D., an associate professor at Northwestern University and clinician at Evanston Northwestern Healthcare.
"We are able to use the optical properties of a cell's structure to serve as a marker for disease," said Backman. "These are changes within the tissue that cannot be detected through any other means. Neither antibodies nor diagnostic assays can detect them."
According to Backman, optical markers are independent of other factors within the tissue microenvironment. "The markers do not change if the patient is a smoker. And the markers do not change with the location, stage or size of the tumor in the pancreas," Backman said.
With the success of the pilot study, the researchers are currently involved in a larger study of the technique and its refinement. They estimate that the technology may be put into practice within three years.
Additional co-authors include Vladimir Turzhitsky and Young Kim of Northwestern University and Hemant Roy, Nahla Hasabou, Charles Sturgis, Dhiren Shah and Curtis Hall of Evanston-Northwestern Healthcare.
The study was supported by funding from the National Science Foundation and the National Institutes of Health.
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