Finding Colon Cancer Sooner

While working on his doctoral degree in medical engineering and medical physics at Harvard University, Vadim Backman thought hard about becoming a medical doctor, but he decided instead to pursue a research career and come to Northwestern. Now medicine and society stand to benefit enormously from that decision.

Colon cancer, the second leading cause of cancer deaths in the country, will be the loser.

Backman, professor of biomedical engineering, his former graduate student Young Kim (GMcC02, 05), now a student in the Feinberg School of Medicine, and their colleagues have developed a promising method for the early detection of colon cancer. Their optical technique, which takes advantage of certain light-scattering effects, can detect abnormal changes in cells lining the colon long before those changes can be seen under a microscope, and even before polyps form.

The colon cancer–screening test is currently in clinical trials at Evanston Hospital in collaboration with Hemant Roy (FSM89), a gastroenterologist with Evanston Northwestern Healthcare. Funded by the National Institutes of Health, the study will have nearly 3,000 participants by the time it ends in three years.

More than 50,000 people die each year in the United States of colon cancer. The disease, however, is easily treated if detected early. Most precancerous lesions appear as polyps, which can be removed during a colonoscopy.

Annual colonoscopies are recommended starting at age 50, but many people avoid the test because of the bowel preparation required. Another reality is that if the approximately 75 million Americans now over 50 actually had the test done, with each colonoscopy costing at least $1,000, the health care system couldn’t handle the financial burden.

“Our hope is that similar to how the routine Pap smear drastically reduced deaths from cervical cancer, this new technology could do the same when it comes to colon cancer,” says Backman. He anticipates their test will cost under $200 and would be used by a physician as part of a routine checkup.

The extraordinarily sensitive technique involves a simple fiber-optic probe the size of a pen being inserted into the rectum. Light shines on the tissue and scatters, and some of it bounces back to sensors in the probe. A computer analyzes the pattern of light scattering, looking for the “fingerprint” of carcinogenesis in the nanoarchitecture of the cells.

“If you have a precancerous lesion in one part of the colon,” explains Backman, “even tissue that looks normal and is located far from the lesion or polyp will have molecular and other kinds of changes. It’s the biological phenomenon called the ‘field effect.’ No one can detect these changes earlier than we can.”

The clinical study is being conducted with patients already slated to get a colonoscopy. More than 500 patients have undergone the new test, which takes only five minutes, followed by a traditional colonoscopy.

The results have been excellent: Backman’s method identified with 100 percent accuracy each person who had a polyp. Some people were singled out who turned out not to have polyps, but that could mean those people need to be watched closely. All those marked as negative had no polyps. — M.F.