RSNA News - April 2005

A press release has been sent to the medical news media for the following scientific article appearing in the April 2005 issue of Radiology (rsna.org/radiologyjnl):

"CT Screening for Lung Cancer: 5-Year Prospective Experience"

CT screening for lung cancer may not help reduce mortality from lung cancer and may, in fact, do more harm than good because of false-positive results and over-diagnosis.

Stephen J. Swensen, M.D., from the Mayo Clinic in Rochester, Minn., and colleagues prospectively studied 1,520 people at high-risk for lung cancer. Each agreed to undergo an annual low-dose helical chest CT scan.

After five annual CT scans, the researchers identified 3,356 uncalcified lung nodules in 1,118 participants (73.6 percent), and 68 lung cancers in 66 participants (4.3 percent).

Forty-eight participants died of all causes since enrollment. The lung cancer mortality rate for the incidence portion of the trial was 1.6/1,000 person-years, which was not significantly different than lung cancer mortality rates in the Mayo Lung Project.

The researchers write: "The ramifications of widespread CT screening for lung cancer are mostly unknown. Our findings answer some questions and raise many others. … The National Lung Screening Trial (NLST), funded by the National Cancer Institute, is a randomized control trial that will determine whether there is a disease-specific mortality benefit. Before the NLST is completed, screening should be performed in the setting of a clinical trial or only after informed consent by a fiduciary without a financial interest."

False-Positive Rates for Lung Cancer Note: Data are number of nodules, unless indicated otherwise. Calculations are based on one or more nodules detected at prevalence or incidence CT examination only. * Excludes the three interval cancers. Two patients with cancer detected at prevalence CT examination had a new primary lung cancer detected on an incidence CT scan and were excluded from incidence analyses.

(Radiology 2005;235:259-265)
© 2005 RSNA. All rights reserved. Printed with permission.

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