Researchers find new ways to detect cancer lesions

March 16, 2010 12:00:00 AM PDT
Bay Area researchers are working to improve the detection of tiny lesions that can carry a big cancer risk. They're a version of traditional polyps, that doctors look for during colonoscopies, but these can be much harder to spot.

Steven, a patient at the VA Hospital in Palo Alto is getting ready to have a colonoscopy. It's a test that may have already saved his life once, when doctors discovered and removed three advanced stage polyps.

"Oh, I might have come down with cancer," he said.

But in addition to traditional polyps, Doctor Roy Soetikno will be looking for a type known as flat lesions.

"The important part about this pancake-looking lesions is that they actually carry a higher risk to contain precancerous or even early cancer," he said.

Traditional polyps hang down from the intestinal wall and resemble mini light bulbs. But flat polyps or lesions can appear as small bumps, be completely flat, or even depressed below the intestine wall.

On-going research by Soetikno and colleagues found the lesions are more prevalent than previously believed among American patients, and these lesions are also harder to spot.

"Certainly, with a cloudy view you cannot see them, when the colon is clean, then you can see them as red patches," Soetikno said.

Soetikno begins by flushing Steven's intestine and he then carefully examines the lining. At first the surface looks clear, but about 15 minutes into the procedure, the surgical team spots the lesion, visible on the screen as a discolored circle.

The doctor inserts a lasso-like device into the catheter and then biopsies the tissue.

"The biopsy will tell us what kind of flat polyp it is, and whether there's already any kind of cancer in it or not," Soetikno said.

Current data indicates flat polyps, though far less common than regular polyps, are up to 10 times more likely to be cancerous, or pre-cancerous. The next phase of research is focused on the genetic differences between these two types of polyps.

"We really don't know why the flat is likelier to become cancerous than the hanging ones, we just have no idea to why that is," Soetikno said.

Finding the answer could eventually save the lives of countless patients like Steven; facing a disease that is now the second leading cause of cancer death in the U.S.

Because the lesions are so close to the intestinal wall, Soetikno is also refining delicate surgical techniques that are used to remove them more safely.

Written and produced by Tim Didion


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