New research continues to demonstrate the benefit of annual lung screening with low-dose CT scans for early detection of lung cancer. A pair of studies published in the Sept. 5 issue of the New England Journal of Medicine represent the latest evidence, appearing in the wake of the United States Preventive Services Task Force draft recommendation that endorses low-dose CT lung cancer screening for long-term smokers.
For one study--part of the National Lung Screening Trial--researchers determined that CT scans caught more early stage lung cancers than X-rays during annual screenings over a three-year period, and the ability to accurately detect cancer improved year after year.
"When we're screening once a year every year we are finding early stage lung cancers that are potentially curable," Caroline Chiles, a professor of radiology in the Comprehensive Cancer Center of Wake Forest Baptist Medical Center and a principal investigator for the study, said, according to HealthDay News. "We really start seeing benefit when someone stays in annual screening."
The benefits of annual screening, Chiles added, should demonstrate that not only are you finding more patients with early stage cancers, but fewer advanced-stage lung cancers, as well.
According to the study, about half of the cancers detected by CT scans in the first and second follow-up years were early-stage cancers, while only 24 percent of the cancers detected by chest X-ray were early stage. At the same time, CT detected half as many cancers as chest X-ray that had progressed to late stage.
"We saw a significant decrease in the number of late-stage lung cancers," Chiles said, according to HealthDay. "We feel we showed a shift to early stage treatable lung cancer in the low-dose CT group."
In a second study, researchers developed a method for sorting potentially dangerous tumors from benign tumors detected during CT lung screening. This checklist--which evaluates factors such as size and location of nodules, as well as smoking and family history--is used to predict whether a nodule is needs to be followed in order to rule out cancer.
According to lead author Stephen Lam, chair of the Provincial Lung Tumor Group and director of the MDS-Rix Early Lung Cancer Detection and Translational Research Program at the British Columbia Cancer Agency, use of the checklist can help doctors avoid performing unnecessary CT exams and reduce patient exposure to radiation or surgery risk.
"Our nodule predictor has an accuracy of over 90 percent in determining whether a nodule needs to be followed up to rule out a cancerous lesion," Lam said.