Targeted contrast agent reveals colon cancer

The Norwegian subsidiary of international medical giant GE Healthcare is conducting pioneering research on new medical procedures based on targeted contrast agents. A new product now under development could play an important role in diagnosing colon cancer. This research receives some of its funding under the Research Council's Programme for User-driven Research-based Innovation (BIA), an open competitive arena with no thematic restrictions.

Common and lethal

Among all cancer types, colon cancer ranks second only to lung cancer in number of deaths caused.

In Norway, one in 24 women and one in 29 men contract colon cancer -- roughly 3 500 people per year. Of these, only half survive five years after being diagnosed.

We believe there is a great deal to gain by improving diagnostics for this type of cancer," says project manager Geir Torheim of GE Healthcare. "There are strong indications that we can now make it far easier to not only find but also remove the most dangerous cancerous polyps in the colon."

Seeks out cancer

Colon cancer was thought to be relatively simple to detect through colonoscopy, a procedure using a camera mounted on the end of a flexible tube to enable doctors to see the mushroom-shaped growths called polyps. An instrument in the same tube is used to excise the polyps.

It has become clear, however, that these easily visible polyps are not the only danger.

"Japanese doctors discovered that there are also flat polyps in the colon that are far more difficult to detect visually," explains Mr Torheim. "The new contrast agent will be valuable for detecting those."

The contrast agent for detecting colon cancer is called GE-137. It is a targeted agent, meaning that once it is injected by needle in the patient's arm, it seeks out the cancer.

New instrument and colon prototype

After roughly 90 minutes the substance has been absorbed in areas where cancer is present.

This is where the other part of the cancer research project comes in: locating the substance is the next step in the procedure. GE Healthcare AS in Norway has drawn on parent company General Electric (GE) -- one of the world's largest conglomerates and a developer of both pharmaceuticals and medical equipment -- to refine the colonoscopy system and camera apparatus used in the project.

GE Global Research, a diversified industrial research laboratory, provided substantial help with the new instrument. It works in much the same way as previous models, but also shines a strong red light. The contrast agent changes the colour of this light so it can be detected by the new camera equipment and compared against regular-colour images.

In a prototype of a colon containing nearly invisible malignant polyps, these dangerous growths are easy to see when the red light is directed on them. The prototype was developed by the research foundation SINTEF in Trondheim.

Aiding surgeons

The contrast agent and medical equipment could greatly ease the task of the surgeons wielding the camera and monitor at the operating table.

The contrast agent has now been fully tested on animal subjects, and researchers have launched a phase-1 clinical trial on people.

GE Healthcare has already examined the substance's effect on healthy volunteers and so far has found no side effects whatsoever. Trials such as these are time-consuming, however, and must be carried out meticulously, so much work remains to be done.