News in brief - Feb. 3, 2003

Scans for lung cancer questioned - Hemochromatosis genes linked to colon cancer risk - Half of women who quit smoking during pregnancy return to the habit

Scans for lung cancer questioned

Computed tomography scans that are widely marketed to consumers may not be valuable for mass screening for lung cancer, cautions a new study by researchers at Johns Hopkins University School of Medicine in Baltimore.

The number of lives saved by annual full-body CT screening may be outweighed by its costs and the harm of unnecessary testing for lung nodules detected by the CT scan that turn out to be benign.

The National Cancer Institute has begun an eight-year trial comparing CT scans with chest x-rays in the diagnosis of lung cancer. Until there is solid data, consumers may want to hold off on the screenings, said the study's senior author Neil R. Powe, MD, MPH, director of Johns Hopkins' Welch Center for Prevention, Epidemiology and Clinical Research. Smoking cessation is the only proven, cost-effective method to reduce lung cancer risk, he said.

Results of the study were published in the Jan. 15 JAMA.

Hemochromatosis genes linked to colon cancer risk

Two of the genes linked to the iron overload disorder hemochromatosis -- C282Y and H63D -- may also lead to an increased risk of developing colon cancer, according to a paper published in the Jan. 15 Journal of the National Cancer Institute.

Researchers at the University of North Carolina in Chapel Hill studied the genes of more than 1,300 subjects. More than 400 already had colon cancer, and they were matched with healthy controls. The scientists also gathered information about possible environmental factors such as iron supplementation, red-meat consumption and nonsteroidal anti-inflammatory use.

Subjects with at least one copy of either mutation were 40% more likely to have colon cancer than those without. Cancer risk increased with age and greater iron intake.

At least 15% of the population is believed to carry at least one copy of the mutated gene.

Researchers suggested that this study could lead to improved colon cancer screening protocols.

Half of women who quit smoking during pregnancy return to the habit

Nearly half of female smokers who become pregnant quit, but more than half of those are unable to remain ex-smokers six months after giving birth, according to a study published in the January American Journal of Preventive Medicine.

Researchers at Pace University in New York analyzed smoking data from 10 states collected between 1993 until 1999 by the Centers for Disease Control and Prevention's Pregnancy Risk Assessment Monitoring System.

They found that quitting during pregnancy rose from 37% to 46%. Just more than 50%, however, returned to smoking, although this varied among groups. Teens were more likely to quit smoking during pregnancy but also more likely to return after delivery. Women with more education were more likely to quit, but those with only a high school education had the lowest relapse rate. Women on Medicaid had the lowest quit rate and the highest relapse rate.

"Targeting anti-smoking therapies at women who have quit during pregnancy may be an effective way to reduce the danger to infants and older children from second-hand smoke," said Gregory J. Colman, PhD, lead author and professor of economics at Pace.