New Research Could Lead to Better Treatment for Lung Cancer
Posted December 14, 2006
Helen Sewell never had any reason to think about lung cancer. She never smoked.
"I had no symptoms. I've never had a symptom of lung cancer," she said.
Yet, a routine chest X-ray 3½ years ago showed that's just what she had. Nonsmokers make up only 10 percent of lung cancer patients. Sewell had surgery to remove a part of her right lung.
"They thought they got it all. It looked good then. But then it came back in six months," Sewell said.
Since then, she has been on five different chemotherapy drugs with varying degrees of success. She has the most common of two types of lung tumors -- non-small cell. However, even among patients with that type, there are different responses to treatment.
Sometimes, chemotherapy is effective and sometimes it is not. Some patients experience metastasis to the brain while others cancer spreads to the bone.
That unpredictability and uncertainty for both patients and oncologists is why UNC researchers thought they might be able to identify different subtypes of non-small cell lung cancer.
"What we describe in the current work is a DNA fingerprint of lung cancer that helps remove some of that uncertainty for patients," said Dr. David Neal Hayes, a UNC oncologist and lead study author.
The DNA fingerprint of a tumor is found through a DNA microarray analysis. Glass slides containing a sample from a tumor go into the analysis machine. An image appears on a computer screen full of colored dots. Each dot is a gene within the tumor. A combination of images reveals genetic patterns that helps doctors identify three tumor subtypes.
The subtypes are bronchoid, squamoid and magnoid. One difference, for example, is bronchoid tumors are less likely to spread to the brain and more resistant to chemotherapy than the others. Researchers said tumor subtypes also determine the likelihood of survival in early or advanced stages of cancer.
"We like to stop dealing with treatments by averages and start tailoring our therapy to individual patients," Hayes said.
Being able to identify subtypes and their characteristics of survival and spread patterns, doctors can design a better treatment strategy.