November 5, 2010
CT Scans May Reduce Lung Cancer Fatalities
A special type of CT scan can help detect lung cancer early in smokers, reducing their mortality rates by 20-percent versus chest X-rays, a new National Cancer Institute (NCI) study has found.
The results come from the National Lung Screening Trial (NLST), a national study of more than 53,000 adults between the ages of 55 and 74, all of whom were currently heavy smokers, or had been previously in their lives. They were also required to have a smoking history of at least 30 "pack-years"--a figure obtained by multiplying the average number of packs of cigarettes smoked per day by the number of years a person has smoked--and no prior history of lung cancer.
The tests began in August 2002 and took place over a 20-month period at 33 sites throughout the U.S. Participants were randomly given either low-dose helical CT scans or standard chest X-rays three times per year, and the results were monitored throughout the trial. Through October 20, a total of 354 lung cancer deaths occurred among those receiving CT scans, compared to 442 for X-ray recipients.
The results were published this week in the online edition of the journal Radiology.
"The findings we're announcing today offer the first definitive evidence for the effectiveness of helical CT screening smokers for lung cancer," Constantine Gatsonis, a lead biostatistician in the study and the director of the American College of Radiology Imaging Network's (ACRIN) Biostatistics and Data Management Center, said in a statement Thursday. "This is a major step in the formulation of appropriate screening strategies for this deadly disease."
"Everyone who participated in this trial has played an important role in providing hard evidence of a mortality benefit from CT screening for lung cancer as well as a road map for public policy development in the future," added Denise R. Aberle, the national principal investigator for NLST ACRIN.
Helical CT scans, also known as spiral CT scans, use X-rays to create a multiple-image scan of a person's entire chest, thus allowing medical professionals to see potential health problems that could otherwise have been masked by other parts of an individual's anatomy.
"This finding has important implications for public health with the potential to save many lives among those at greatest risk for lung cancer," NCI Director Harold Varmus told Washington Post Staff Writer Rob Stein. "This finding will be an important factor in subsequent efforts to protect the tens of millions of former and current smokers in this country against the lethality of lung cancer."
Previous research into the matter conducted by Dr. Claudia Henschke from the Mount Sinai School of Medicine has shown even greater success, according to a Thursday article by Reuters Health and Science Editor Maggie Fox. Henschke worked on a research team that in 1999 claimed that spiral CT scans could detect up to 85-percent of small lung tumors while they were still removable. She and her colleagues also reported similar success in a 2006 New England Journal of Medicine study.
Henschke told Fox that she was "thrilled" about the results of the new study, "because it makes such a difference for people's lives." At the same time, though, she expressed frustration that her earlier research was often ignored or dismissed, telling Fox, "This has now taken 10 years"¦ If you think about it, in the United States we have 160,000 deaths each year from lung cancer. That's 1.6 million."
Image Caption: Computed tomography examines the lungs from many perspectives. It reduced lung cancer deaths by 20 percent compared to using chest X-rays in a major national study. Credit: ACRIN
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