Colon cancer is the third-most-common cancer in men and women, with about 150,000 people diagnosed each year.

Typically it is detected through a colonoscopy, when a doctor takes a sample called a biopsy, and sends it to a pathology lab to screen for cancer. The problem is the step takes time and not all people have such immediate access to a pathologist. What also happens is that doctors biopsy only the cancers that form easily visible growths called polyps. The early-stage cancers remain flat and can't be detected.

A new technique developed by a team of researchers at the Stanford University School of Medicine (Stanford, California) is opening up the door for doctors to be able to detect early stages of colon cancer without a biopsy and at a much quicker pace. Christopher Contag, PhD, an associate professor of pediatrics and of microbiology and of immunology, at Stanford led the study, which was funded through the National Institutes of Health (NIH), the Doris Duke Charitable Foundation, the Stanford School of Medicine Dean's Fellowship and the John and Cynthia Fry Gunn Research Fund. Contag said he hoped the technique might be one of the first to be routinely for early detection of cancer.

Study results were published online on March 16th in Nature Medicine.

The technique, which has been described as real-time cancer screening, is comprised of two parts. The first is the development of a new peptide attached to a fluorescent beacon that sticks to cancerous cells and creates an easily visible fluorescent patch.

The key in detecting cancer without a biopsy is to find a way of seeing which cells are cancerous while they are still in the body and that's something this technique has been proven to do.

The short protein sticks to colon cells in the early stages of cancer. Before screening a person, the researchers would spray the short protein attached to a fluorescent beacon into the colon. The protein then gloms on to any cancerous cells and creates that fluorescent patch.

The second part of the technique relies on the use of Cellvizio's (Newton, Pennsylvania) miniaturized microscope, the Cellvizio GI, which is a confocle probe-based technology that gives researchers a better look at the colon, or in this case, the fluorescent patch created from the protein attaching to the cancerous tissue in the colon.

"The probe itself is a flexible probe. It's about 2.5 mm in diameter and it goes through the working channel of a conventional endoscope, and the probe itself is attached to a software that allows for a visual depiction of the scanned area," Chris Tihansky, president of Cellvizio, told Medical Device Daily.

The microscopic view of cells is displayed on a screen in the operating theater adjacent to the endoscope's macro view allowing a clinician to perform what is called an "optical biopsy" of suspect tissue; thereby significantly reducing the number of tissue samples extracted for lab analysis from an average of 24 to half a dozen.

In the initial trial with 15 patients, the technique detected about 82% of the polyps that were considered cancerous by a pathologist. Contag said the next step for the research team is to work with some of the additional small proteins they've found that also attach to cancerous cells. He added that the combination of those proteins would make the technique more accurate.

In the future there are plans to adapt the technique to detect cancers in the mouth, esophagus and stomach. In addition this sort of real-time screening could be used as a way of determining if chemotherapy is working. For instance, if a tumor responds to a given chemotherapy, changes in the cells might be visible immediately that response could allow for doctors to switch patients to more effective treatments if the first one doesn't have any improvements.

For Cellvizio, which is a subsidiary of Mauna Kea Technologies (Paris), plans call for the spread of the device to be used in the lungs and other parts of the body.

"I think we feel there are many other applications we can use the device for," Tihansky said. "Right now we're only approved for gastroenterological and pulmonary procedures."

The device received FDA clearance in 2005, and was developed by Mauna Kea Technologies.

Cellvizio has had a presence in the U.S. for about three years but it was significantly boosted last year through a $30 million financing led by the Psilos Group. The company closed on the financing earlier this year (Medical Device Daily, Jan. 29, 2008). It was part of an effort to maximize the company's U.S. presence.