Benefit small from lung cancer screening method
11 june 2008--A high-tech X-ray called a spiral CT scan may help reduce lung cancer deaths in smokers and former smokers, but only reduces their overall risk of premature death by 4 percent, researchers reported on Tuesday.
Heart disease, respiratory disease and other types of cancer are still highly likely to kill smokers and former smokers early, the team at Harvard Medical School and the Mayo Clinic in Rochester, Minnesota, found.
Their study, published in the journal Radiology, will likely add to a debate on the value of screening smokers for lung cancer.
"Our study suggests that screening may be one way to reduce risk of death from lung cancer," Dr. Pamela McMahon of Massachusetts General Hospital and Harvard said in a statement.
"However, the number-one goal should still be to quit smoking, because it will reduce risk of death from many causes, including lung cancer."
Lung cancer is the leading cause of cancer death in the United States -- the American Cancer Society estimates it will kill 168,840 people in 2008. About 87 percent of lung cancer cases are caused by smoking.
It is so deadly in part because it causes few symptoms in early stages -- only 15 percent of lung tumors are found before they have spread. If diagnosed in the earliest stages, half of lung cancer patients live five years or more, but that survival rate drops to 2 percent for people diagnosed in later stages.
Some experts have proposed spiral computed tomography, or spiral CT scans, as a way to screen smokers and other high-risk people.
McMahon's team looked at a study done at the Mayo Clinic of 1,520 current and former smokers who got helical, or spiral, CT scans. They entered data into a computer model of lung cancer development.
The computer projection showed that patients who had five annual screenings had an estimated 37 percent relative increase in lung cancer detection, compared with those who had not been screened. The relative reduction in lung cancer-specific death was 28 percent.
But they said those who were screened would be only 4 percent less likely to die of all causes, compared with people not screened.
After 15 years, those who got screened annually would be 15 percent less likely to have died of lung cancer and 2 percent less likely to have died of anything.
"Our study fills in a piece of the puzzle but does not solve it," McMahon said in a statement. "We are hopeful that randomized trials conducted by the National Cancer Institute will show a benefit from screening. Until then, patients should think carefully about undergoing a test that has no direct evidence of benefit."
Some experts worry that screening can lead to detection of tumors that would never have grown into something serious for the patient.
X-rays can also find lesions that must be tested with a biopsy -- a small piece of tissue -- taken from the lung. Taking a biopsy carries a small risk of collapsing a lung.
11 june 2008--A high-tech X-ray called a spiral CT scan may help reduce lung cancer deaths in smokers and former smokers, but only reduces their overall risk of premature death by 4 percent, researchers reported on Tuesday.
Heart disease, respiratory disease and other types of cancer are still highly likely to kill smokers and former smokers early, the team at Harvard Medical School and the Mayo Clinic in Rochester, Minnesota, found.
Their study, published in the journal Radiology, will likely add to a debate on the value of screening smokers for lung cancer.
"Our study suggests that screening may be one way to reduce risk of death from lung cancer," Dr. Pamela McMahon of Massachusetts General Hospital and Harvard said in a statement.
"However, the number-one goal should still be to quit smoking, because it will reduce risk of death from many causes, including lung cancer."
Lung cancer is the leading cause of cancer death in the United States -- the American Cancer Society estimates it will kill 168,840 people in 2008. About 87 percent of lung cancer cases are caused by smoking.
It is so deadly in part because it causes few symptoms in early stages -- only 15 percent of lung tumors are found before they have spread. If diagnosed in the earliest stages, half of lung cancer patients live five years or more, but that survival rate drops to 2 percent for people diagnosed in later stages.
Some experts have proposed spiral computed tomography, or spiral CT scans, as a way to screen smokers and other high-risk people.
McMahon's team looked at a study done at the Mayo Clinic of 1,520 current and former smokers who got helical, or spiral, CT scans. They entered data into a computer model of lung cancer development.
The computer projection showed that patients who had five annual screenings had an estimated 37 percent relative increase in lung cancer detection, compared with those who had not been screened. The relative reduction in lung cancer-specific death was 28 percent.
But they said those who were screened would be only 4 percent less likely to die of all causes, compared with people not screened.
After 15 years, those who got screened annually would be 15 percent less likely to have died of lung cancer and 2 percent less likely to have died of anything.
"Our study fills in a piece of the puzzle but does not solve it," McMahon said in a statement. "We are hopeful that randomized trials conducted by the National Cancer Institute will show a benefit from screening. Until then, patients should think carefully about undergoing a test that has no direct evidence of benefit."
Some experts worry that screening can lead to detection of tumors that would never have grown into something serious for the patient.
X-rays can also find lesions that must be tested with a biopsy -- a small piece of tissue -- taken from the lung. Taking a biopsy carries a small risk of collapsing a lung.
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