Original Article
Screening/Epidemiology
Lung Cancer Incidence and Mortality with Extended Follow-up in the National Lung Screening Trial

https://doi.org/10.1016/j.jtho.2019.05.044Get rights and content
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Abstract

Introduction

The National Lung Screening Trial (NLST) randomized high-risk current and former smokers to three annual screens with either low-dose computed tomography (LDCT) or chest radiography (CXR) and demonstrated a significant reduction in lung cancer mortality in the LDCT arm after a median of 6.5 years' follow-up. We report on extended follow-up of NLST subjects.

Methods

Subjects were followed by linkage to state cancer registries and the National Death Index. The number needed to screen (NNS) to prevent one lung cancer death was computed as the reciprocal of the difference in the proportion of patients dying of lung cancer across arms. Lung cancer mortality rate ratios (RRs) were computed overall and adjusted for dilution effect, with the latter including only deaths with a corresponding diagnosis close enough to the end of protocol screening.

Results

The median follow-up times were 11.3 years for incidence and 12.3 years for mortality. In all, 1701 and 1681 lung cancers were diagnosed in the LDCT and CXR arms, respectively (RR = 1.01, 95% confidence interval [CI]: 0.95–1.09). The observed numbers of lung cancer deaths were 1147 (with LDCT) versus 1236 (with CXR) (RR = 0.92, 95% CI: 0.85–1.00). The difference in the number of patients dying of lung cancer (per 1000) across arms was 3.3, translating into an NNS of 303, which is similar to the original NNS estimate of around 320. The dilution-adjusted lung cancer mortality RR was 0.89 (95% CI: 0.80–0.997). With regard to overall mortality, there were 5253 (with LDCT) and 5366 (with CXR) deaths, for a difference across arms (per 1000) of 4.2 (95% CI: –2.6 to 10.9).

Conclusion

Extended follow-up of the NLST showed an NNS similar to that of the original analysis. There was no overall increase in lung cancer incidence in the LDCT arm versus in the CXR arm.

Keywords

Lung cancer
Screening
Low-dose CT
Incidence
Mortality

Cited by (0)

Disclosure: Dr. Aberle reports grants from American College of Radiology Imaging Network (ACRIN), grants from American College of Radiology Imaging Network (ACRIN), during the conduct of the study; other from 2016 Veracyte Advisory Board, non-financial support from 2016: Moffitt Cancer Center, grants from 2016: Kaiser Radiology Symposium, grants and other from 2016: MCL Consortium Meeting, non-financial support from 2016: ECOG-ACRIN Semi Annual Meeting, grants from 2016 DECAMP Consortium Meeting, other from 2016: American Society of Clinical Oncology (ASCO) Annual Meeting, non-financial support from 2016: National Academy of Sciences Workshop, non-financial support from 2016: Siemens Annual UCLA Research Meeting, personal fees from 2016: Veracyte Advisory Board Meeting, personal fees and non-financial support from 2016: International Lung Cancer Congress (ILCC) Meeting, grants and non-financial support from 2016: MCL Consortium Meeting, non-financial support from 2016: Harvard University Chest Imaging Course, personal fees from 2016: Torrance Medical Center Grand Rounds, personal fees and non-financial support from 2016: Yale Grand Rounds, CT, other from 2016: ASCO, non-financial support from 2016: NCI Workshop, Washington DC, grants and other from 2017: MCL Houston, personal fees and non-financial support from 2017: National Jewish Health, other from 2017: World Congress Thoracic Imaging, non-financial support from 2017: American College of Radiology, other from 2017: EDRN Steering Committee Meeting, personal fees from 2017: NIH Section Review, grants from 2017: Kaiser Watch the spot meeting, Pasadena, other from 2018: Grand Rounds WLAVA, personal fees from 2018: NIH Section Review, San Diego, grants from 2018: DECAMP 2018 Meeting, personal fees from 2018: International Symposium on “Clinical update in Respiratory Medicine”, grants from 2018: EDRN, Bethesda, grants from 2018: MCL, Bethesda, non-financial support from 2018: AIMBE College of Fellows, non-financial support from 2018: Cleveland Clinic Visiting Professor, non-financial support from 2018: SPORE Workshop - Lung Cancer, non-financial support from 2018: IASLC, Toronto, grants from 2018: MCL Steering Committee, personal fees from 2018: Cancer Research UK (CRUK), other from 2018: RSNA, outside the submitted work. Dr. Sicks reports a grant to her institution from the National Cancer Institute (grant U10CA18-820-0151) during the study. Dr. Chiles reports a grant to her institution from the National Institutes of Health (grant CA 80098) during the study. The remaining authors declare no conflict of interest.

Address for correspondence: Paul Pinsky, PhD, National Cancer Institute, 9609 Medical Center Dr., Bethesda, MD 20892. E-mail: [email protected]

∗

A complete list of members of the National Lung Screening Trial Research Team is provided in the Appendix.

Published by Elsevier Inc. on behalf of International Association for the Study of Lung Cancer.