CT Scans Can Detect Lung Cancer That X-Rays Cannot

Nov. 10, 2005 — -- Colleen Crayton smoked for more than 40 years before she quit. After hearing of Peter Jennings' battle with lung cancer, she decided to ask for a CT lung scan even though she no longer smoked and had no symptoms.

"I did not think that there was a chance that I was going to be found with cancer in my lung," she said.

Crayton believes the scan may have saved her life. A small tumor was found in her right lung. She had it removed a week later and is undergoing chemotherapy.

"If I had not done this scan when I did, well, that's all she wrote. It's over," she said.

By the time symptoms appear, lung cancer has usually spread beyond the lungs and the five-year survival rate is only 15 percent. Studies have shown traditional chest X-rays do not catch lung cancer early enough to reduce the death rate. That's why some researchers are so enthusiastic about the new, more sensitive CT scans.

Dr. Claudia Henschke started the Early Lung Cancer Action Program at New York Presbyterian Hospital 10 years ago and more than 30,000 people have received scans in the program.

"Eighty percent of the cancers we find are of early stage, where it hasn't spread, where if you take it out, it can be cured," Henschke said.

The scan takes only a few minutes and delivers approximately 260 images of the lungs. In one patient, two tumors about 4 centimeters in size that were clearly visible on the CT scan did not show up at all on the X-ray. That's why many people at high risk for lung cancer have chosen to get CT scans even though they are not covered by insurance.

So, should every current and former smoker get a CT scan? The American Cancer Society says not yet.

"We're waiting for the evidence to find out whether or not these are really effective in decreasing the rate of death from lung cancer," said Dr. Len Lichtenfeld of the American Cancer Society.

While CT scans can identify small tumors in the lung, some researchers say there is no proof yet that finding them actually saves lives. They say early detection may simply lead to a longer period of treatment without any change in ultimate outcome.

Furthermore, said Lichtenfeld, "They may have always been there, they may never have caused a problem so we don't know how much of the cancer we're finding would have been, in fact, a problem for patients."

CT scans can also result in additional risks for the patient. Once a suspicious spot is found, invasive biopsies are usually ordered, which can result in infection or collapsed lungs. That is why many medical groups say before a recommendation is made for regular screening of 90 million current and former smokers, they want to be certain the test saves lives.

ABC News' Dr. Tim Johnson filed this report for "World News Tonight."