RSNA 2019 CT Preview

Is it time to individualize CT lung screening intervals?

By Abraham Kim, staff writer

November 7, 2019 --

Wednesday, December 4 | 10:50 a.m.-11:00 a.m. | SSK05-03 | Room N229
Tailoring the interval between baseline and follow-up CT lung screening exams based on an individual's risk of lung cancer could safely reduce the rate of unnecessary screening exams, say researchers from Italy.

As part of the Multicentric Italian Lung Detection (MILD) trial, Dr. Mario Silva and colleagues from the University of Parma explored the benefits of determining lung cancer risk for individuals with a negative baseline CT lung screening exam before deciding on the most appropriate interval between initial and follow-up screening for each case.

"The present analysis represents a renewed concept of the early inception of the MILD trial: Is annual screening worthwhile in every subject?" Silva told

The researchers put this question to the test by applying a computer-aided diagnosis algorithm to the CT scans of 1,248 participants in the U.S. National Lung Screening Trial. The semiautomatic algorithm classified all the detected solid and subsolid lung nodules by volume, with greater nodule volume indicating higher cancer risk.

They found that individuals with the highest nodule volume (greater than 260 mm3) were at risk of having lung cancer within three months, suggesting that a follow-up CT exam closer to three months would be more suitable than the standard annual exam. In addition, those determined to have the lowest nodule volume (less than 112 mm3) were unlikely to have lung cancer within the first three years after initial screening.

Following this risk stratification, Silva and colleagues simulated CT lung cancer screening in the cohort by assigning triennial screening for individuals in the lowest nodule volume category and either biennial or annual screening for those in the middle and highest volume categories. This approach would have reduced unnecessary CT exams by as much as 35%, they discovered.

"The proposed approach is examined by simulations at both two and three years, showing the safety of a prolonged screening interval up to two years and the potential reduction of low-dose CT burden" of both radiation exposure and costs, Silva said.

Last Updated np 11/6/2019 11:54:20 AM