A study may have found a way to potentially decrease the rate of lung cancer in high-risk patients. For former heavy smokers and other high-risk lung cancer patients, a low-dose CT screening that clears them of the disease may be sufficient to keep them from returning the following year for another look — in fact it may be preferable.

By examining the records of 19,066 patients from the National Lung Screening Trial, the team, led by Dr. Edward F. Patz, Jr., the James and Alice Chen Professor of Radiology at Duke and lead author of their study, randomly assigned their participants, ages 55 to 74, who had smoked for the equivalent of 30 years, to either receive three annual low-dose CT scans or three chest radiographs for the early detection of lung cancer.

“We are trying to identify a subgroup of patients, even in the smokers, who may not need an annual screening procedure,” Patz told HCB News, “Instead of being in the high risk category, how can they become a lower risk category?”
The researchers identified study participants in the CT-scan group whose initial screening was negative. They then compared those patients to other CT-scan recipients whose screenings detected an abnormality, in order to analyze any differences in lung cancer incidence and lung cancer-specific deaths.

For the initial individuals with negative initial LDCT scan, 444 patients, or two percent, were diagnosed with lung cancer at their last available follow-up appointment.

In the first year after a negative screen and before the first scheduled annual screen, 17 patients, or .09 percent, were diagnosed with lung cancer. An additional 75 patients, or .4 percent, were diagnosed with lung cancer between the first and second annual screening.

Eliminating the first annual screening after the initial negative test might have resulted in, at most, an additional 28 lung cancer deaths in the LDCT group, 186 deaths compared to the 212 deaths per 100,000 per year, over the course of the seven year study, according to the researchers.

"Our analysis suggests that annual screens may not be warranted for patients who have had an initial negative scan, and future risk prediction and cost-effectiveness models could incorporate these data to improve screening guidelines," stated Patz.

Roughly 40 percent of the patient population had false positives sometime during the study. Patz added that improving the accuracy of LDCT screening for lung cancer would significantly reduce the number of annual screens.

“We have had patients with false positives and that’s part of the problem. Patients get worked up, they have biopsies, PET scans, sequential imaging, but they don’t necessarily have cancer,” said Patz.

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