Michael K. Gould, MD, MS, pulmonologist and director of the Division of Health Services Research and Implementation Science at Kaiser Permanente Southern California, discusses the implications of the NELSON trial in lung cancer.

Findings from the NELSON trial showed a 24% reduction in lung cancer mortality in high-risk patients who underwent volume CT screening. Unlike the National Lung Screening Trial (NLST), investigators did not find an associated reduction in all-cause mortality; however, that may be due to the smaller size of the trial, says Gould. In both studies, screening carried a risk of a false-positive test result. In the NLST, about 40% of patients had at least 1 positive test result after 3 rounds of screening and over 95% of those positive findings were false positives. Now that the benefit of screening has been demonstrated, investigators are working to reduce the false-positive rate or find ways to distinguish between a true positive and false-positive result, says Gould.

Notably, in the NELSON trial, investigators used nodule volume and volume-doubling time to calculate the size of the tumor. Anyone who had a nodule of a certain size came back 3 months later for a follow-up scan and, if the nodule was still present, it was remeasured. The comparison between the size of the nodule on the baseline screening test and the size of the nodule on the follow-up tests demonstrated that benign growths were mostly scar tissue, concludes Gould.

Michael K. Gould, MD, MS

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Dr. Gould on the Implications of the NELSON Trial in Lung Cancer