Clinical Pearls & Morning Reports
Published February 5, 2020
The Dutch–Belgian lung-cancer screening trial (Nederlands–Leuvens Longkanker Screenings Onderzoek [NELSON]), a population-based, randomized, controlled trial initiated in 2000, aimed to show a reduction in lung-cancer mortality of 25% or more with volume-based, low-dose computed tomography (CT) lung-cancer screening in high-risk male participants at 10 years of follow-up. A total of 13,195 men (primary analysis) and 2594 women (subgroup analyses) between the ages of 50 and 74 were randomly assigned to undergo CT screening at T0 (baseline), year 1, year 3, and year 5.5 or no screening. Read the NEJM Original Article here.
Q: What percentage of patients with lung cancer are alive 5 years after diagnosis?
A: Lung cancer is the leading cause of death from cancer worldwide (18.4% of all cancer deaths) and causes more deaths than breast, colorectal, and cervical cancer combined — cancers for which population-based screening programs exist. Only 15% of patients with lung cancer are still alive 5 years after diagnosis, because approximately 70% of patients have advanced disease at the time of diagnosis.
Q: What were the findings of the U.S.-based National Lung Screening Trial?
A: The U.S.-based National Lung Screening Trial (NLST) showed that a strategy of three annual CT screenings resulted in 20.0% lower morality from lung cancer than screening with the use of chest radiography among 53,454 participants at high risk for lung cancer after a median follow-up of 6.5 years, and the trial recently confirmed that mortality at a median follow-up of 5.5 and 6.0 years was as much as 19% lower with CT screening as with chest radiography.
A: In the NELSON trial, volume CT lung-cancer screening of high-risk former and current smokers, with the introduction of growth-rate assessment as an imaging biomarker for indeterminate tests, resulted in low referral rates for additional assessments and substantially lower lung-cancer mortality (in both sexes) than no screening, despite screening intervals that increased over time. In line with the mortality outcomes, volume CT screening in the NELSON trial has led to a substantial shift to lower-stage cancers at the time of diagnosis as well as to more frequent eligibility for curative treatment (mainly surgical).
A: Trial data suggest greater benefits in women than in men, but in a subgroup with a relatively low number of women. More research is required in women, as well as in other subgroups. Post hoc analyses from the NLST also showed weak evidence of a differential effect size according to sex and histologic type. Recently, the German Lung Cancer Screening Intervention Trial showed a significant benefit with respect to lung-cancer mortality in the small subgroup of women who were invited to undergo screening (hazard ratio, 0.31; 95% CI, 0.10 to 0.96).