Debra S. Dyer, MD, FACR, chair of the American College of Radiology Lung Cancer Screening 2.0 Steering Committee, contributed this post.
On June 28, 2019, the Journal of Thoracic Oncology published an update to the National Lung Screening Trial (NLST). The new study reports a sustained reduction in cancer deaths from low-dose computed tomography (LDCT) lung screening roughly 12 years after the initial screening exam.
This is good news, and adds to the ever-growing body of evidence that lung cancer screening with LDCT is effective.
The study found the incidence of lung cancer to be nearly the same in both the LDCT group and the chest radiograph (CXR) groups. Lung cancer mortality was 3.3 points lower in the LDCT group (42.9 per 1000) compared to the CXR group (46.2 per 1000), which is similar to the 3.1 points noted in the original NLST study results.
A significantly higher proportion of patients in the LDCT group (39.6%) were found to have Stage 1 cancers compared to the CXR group (27.5%). Fewer in the LDCT group (17.5%) were found to have Stage IV cancer compared to CXR group (22.3 %). This shows persistence of a stage shift with CT screening.
The Number Needed to Screen (NNS) to prevent one death was 303, slightly less than the 320 which was reported in the original study. The stability of the difference in NNS over time indicates that LDCT screening did not just delay lung cancer death by a few years, but prevented it.
In addition, the overdiagnosis rate fell to 3.1%, considerably less than 18% in the original study.
By demonstrating a similar and sustained mortality benefit as the original study, the extended follow-up of NLST confirms what the ACR Lung Cancer Screening 2.0 Steering Committee (ACR LCS 2.0) knows: that LDCT is effective, and that more lives can – and will – be saved by its effective utilization.
To learn more about how ACR LCS 2.0 is addressing the barriers, identifying solutions and empowering radiologists to lead efforts to increase LDCT adoption, register for our free Lung Cancer Screening Boot Camp Web Series and visit the Lung Cancer Screening Resources page on acr.org.