- The Washington Times - Thursday, August 11, 2005

A key reason lung cancer is the deadliest cancer in America is that it is rarely detected early and usually has spread beyond the lungs when diagnosed.

There is no established screening test for lung cancer, which killed ABC News anchor Peter Jennings this week and is afflicting Dana Reeve, widow of actor and director Christopher Reeve.

But that could change as a result of clinical studies that are trying to determine whether a new X-ray technique known as low-dose spiral CT scanning can detect lung cancer early enough to save lives in those most at risk.

This year, lung cancer will kill about 90,000 men and 73,000 women, according to the American Cancer Society (ACS). The five-year survival rate for people diagnosed with lung cancer is about 13 percent.

A study under way called the National Lung Screening Trial is examining nearly 53,500 smokers and former smokers. It is sponsored by the National Cancer Institute (NCI). The ACS assisted with recruitment.

Dr. Christine D. Berg, chief of the Early Detection Research Group in NCI’s Division of Cancer Prevention and leader of the study, said every participant had smoked a pack of cigarettes daily for at least 30 years.

“We have reason for hope that with this trial we’ll have a [screening] tool … we see great possibilities … and we should definitely be excited about these possibilities,” said Dr. Thomas Glynn, director of science and trends for ACS.

The ACS Web site says spiral CT scanning already has proven “successful in detecting early lung cancers in smokers and former smokers.”

However, Dr. Glynn said: “It is not approved for use as a lung [screening] tool, as there is no evidence it reduces lung cancer mortality. So we can’t recommend it until we get the results from the trial.”

Still, Dr. Berg was optimistic about the effect spiral CT scans could have on lung cancer rates.

She said trial investigators anticipate a 20 percent reduction in lung cancer mortality because of the scans. “That would be significant, since it would mean 30,000 lives saved a year,” Dr. Berg said.

Among the known benefits of spiral CT scans, said Dr. Paul Bunn, director of the University of Colorado Cancer Center, is that they “use less radiation and are cheaper to use” than traditional chest X-rays and produce three-dimensional, rather than two-dimensional, images.

“They are very good at finding nodules in the lungs and can see those behind the ribs or heart, which can’t be seen in two dimension. Spiral CT scans can find smaller nodules, since it can detect them much earlier” than other diagnostic techniques, said Dr. Bunn, who also is executive director of the International Association for the Study of Lung Cancer.

But he and Dr. Glynn said it has not been proven that spiral CT scans will lower the chances of dying from lung cancer.

And because of that, neither private nor government health insurers will pay for the procedure, which ranges from $300 to $1,200.

One major problem with the spiral CT test is that it finds a lot of abnormalities that turn out not to be cancer. This can lead to a lot of unnecessary worry, testing and even surgery.

“Fifty percent or more” of growths detected with spiral CT scans “can be false positives,” Dr. Glynn said.

The ACS says false positives are “common” with spiral CT scanning.

Dr. Berg said she expects the large number of false positives will be “a difficult problem to get around” and anticipates a “multipronged approach” for lung cancer screening.

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