Science Video

Shedding Light On Colon Cancer
Gastroenterologists Use Optics To Detect Early Stages Of Colon Cancer

January 1, 2008 — Biomedical engineers have developed a new technique to detect colon cancer. A thin optical fiber shines light onto the interior of the colon. Computer analysis of the backscattered light indicates if the colon is a breeding ground for polyps. This technique can detect changes in the cells very early in the development of polyps. The technique is also used to detect

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When colon cancer symptoms appear, the cancer is often already at an advanced stage. To catch it early, regular screening is a must. Soon, screening for colon cancer may not only be a whole lot easier -- but could also detect it earlier than ever before.

"Over 150,000 Americans will be diagnosed with colon cancer." Hemant Roy, M.D., gastroenterologist at Evanston Northwestern Health Care in Evanston, Ill., told Ivanhoe.

It's a statistic that worries gastroenterologist Dr. Roy -- only half the people who need a colonoscopy will get one.

While colonoscopies are effective, they're also invasive. Now, Dr. Roy says this tiny light could be the next best defense. This technique is sensitive to things 10 to 20 times smaller than can be seen with a conventional microscope. The light scattering probe spots danger before polyps ever form.

"Since this will be minimally intrusive, maybe we can get more of the people screened," Dr. Roy said.

The probe is tiny compared to a standard colonoscope and it lights up rectal tissue with no need to go through the whole colon. Computer analysis of the backscattered light shows if the colon is a breeding ground for polyps. In studies, the probe is 90 percent accurate at telling if cancerous polyps will form.

Twenty-seven year old Reid Foster knows he has the colon cancer gene. "Starting at age 25, I started getting colonoscopies," said Foster.

He's had the new light probe too and says the difference is night and day.

"You just look at the diameter, I mean, it's an optical fiber versus something the diameter of a drumstick. I mean, you just tell that to somebody, most people would choose fiber!" said Foster.

It's an obvious benefit, but be patient. The probe is about five years away from FDA approval.

WHAT ARE COLONOSCOPIES? Colonoscopies are viewed as the "gold standard" for catching colorectal cancer before it has a chance to take root and spread. Gastroenterologists recommend that men and women over the age of 50, without a risk of colon cancer, get a colonoscopy every ten years, while those at high risk should receive one earlier and more frequently. In colonoscopies, physicians visually examine the lining of the colon and rectum. Upper endoscopies are used to examine the esophagus, stomach and the upper part of the small intestine (the duodenum).

The colonoscope is a thin flexible instrument measuring between 48 inches to 72 inches long. It has a small video camera attached to the end so it can record images of the large intestine. The "scope" is passed through the rectum and into the colon to directly examine the lining of the lower digestive tract -- a full five feet of twists and turns.

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.