Chest CT scans detect early-stage lung cancer

Annual computed tomography screening of the chest makes it more likely that, if a lung cancer is detected, it is at stage I when it is most curable, according to a paper presented at the Radiological Society of North America meeting in Chicago last month.

Researchers from the International Early Lung Cancer Action Program analyzed data collected from more than 26,000 people who, since 1993, have received CT scanning in conjunction with this study. The project is a collaboration of scientists around the world who are investigating ways to improve this cancer's cure rate.

Screening led to the diagnosis of more than 300 cancers with 82% at stage I. On the basis of these data, the paper's authors are recommending that those at high risk, such as smokers, consider annual screening.

"We feel you should individualize this decision," said Claudia I. Henschke, MD, PhD, principal investigator and professor of radiology at Cornell Medical Center in New York. "And then it's up to you if you want to pay that money to be screened."

Other experts said, though, that while the numbers were interesting, they were still not conclusive enough to change recommendations -- most of which are lukewarm on lung cancer screening.

Medical societies recommend that patients only undergo such tests within the context of a clinical trial.

In May, the U.S. Preventive Services Task Force issued a statement acknowledging that there were fair data that screening detected these cancers early, but poor data that it had any impact on mortality. Thus, the task force's expert panel said there was insufficient evidence to recommend either for or against the strategy.

"If you want to get into a trial, that's fine," said Edward F. Patz Jr., MD, professor of radiology, pharmacology and cancer biology at Duke University in Durham, N.C. "But right now there are no data that suggest screening will actually reduce mortality." Dr. Patz is involved in the National Lung Cancer Screening Trial, which is also investigating this question.

Other developments

While some researchers are looking for ways to screen for lung cancer, others are seeking ways to improve mammography, particularly for women at high risk for breast cancer.

These cancers, which are mostly in young women, are more likely to be missed by mammography. A study presented at the meeting by the International Breast Magnetic Resonance Consortium Trial suggested that magnetic resonance imaging can identify these tumors.

"MR findings resulted in 6% of women with a negative mammogram and a negative clinical breast exam being recommended for biopsy," said Constance Dobbins Lehman, MD, PhD, lead author and director of breast imaging at the University of Washington Medical Center in Seattle. "Three additional cancers were detected in those women."

The U.S. Preventive Services Task Force has no policy on this issue, although the American Cancer Society says that additional tests such as MRI should be considered by women at high risk.

But cancer may not be the only medical condition that these screening tests can identify. According to another study presented at RSNA by researchers at the Mayo Clinic in Jacksonville, Fla., virtual colonoscopy may detect heart attack risk.

Researchers reviewed the records of nearly 500 patients who had the procedure at the Mayo Clinic in Rochester, Minn., and gathered information about calcification in the abdominal aorta. Their findings: The higher the score, the more likely the patient was to have a cardiac event. Additionally, this score correlated well with other known risk factors such as hypertension.

"This early study points to the possibility of multiple diagnostic benefits for patients participating in certain colon cancer screenings," said lead author, Jesse A. Davila, MD, a fellow in musculoskeletal radiology at the Jacksonville Mayo Clinic.

The USPSTF recommends that those older than 50 be screened for colon cancer but says there are insufficient data to recommend virtual screening.

An American Gastroenterological Assn. expert panel concluded this month that this method had significant promise but that the technology is still evolving.