New data supports previous studies that low-dose CT (LDCT) lung cancer screening can effectively reduce the risk of patients dying of lung cancer.
The United Kingdom Lung Cancer Screening (UKLS) trial confirms that LDCT reduces lung cancer mortality. A meta-analysis of nine randomized clinical trials including the UKLS data showed a 16 percent relative reduction in lung cancer mortality when compared against a non-LDCT control arm, reported John Field, PhD, of the University of Liverpool in England, at the IASLC 2021 World Conference on Lung Cancer. Previous studies, such as the National Lung Screening Trial and The NELSON LDCT screening trial, provided evidence of a statistically significant reduction (20% and 24%, respectively) in lung cancer mortality.
Study Details
The randomized controlled UKLS trial compared LDCT screening with usual care in a high-risk population. Risks for the UKLS were calculated using a modified version of the Liverpool Lung Project model that incorporates age, smoking duration, family history of lung cancer, history of previous malignancies, and exposure to asbestosis. It also includes other potential respiratory risk factors (bronchitis, emphysema, tuberculosis, and COPD), in addition to pneumonia, and treats cigar and pipe smoking as conferring an identical risk to cigarette smoking.
The researchers enrolled 4,055 participants from October 2011 to February 2013, with either a single invitation to LDCT screening or no screening (usual care). Data were collected on lung cancer cases and deaths to February 29, 2020, through linkage to national registries. The primary outcome was mortality due to lung cancer.
After a median follow-up of 7.4 years, Field's team analyzed 1,987 UKLS participants in the intervention arm and 1,981 in usual-care arm. During this time, 30 lung cancer deaths were reported in the screening arm and 46 deaths in the control arm. The primary analysis showed a relative rate of 0.65; (RR 0.65, 95% CI 0.41-1.02, P=0.062).
There was not a statistically significant difference between the two arms, but Field noted that the relative benefit in terms of lung cancer mortality was seen most strongly in the 3-6 years after randomization and continued for the 7-year follow-up period.
There were no differences in lung cancer mortality between male and female subgroups. There was a non-significant increase in the incidence of lung cancer for men and women. The benefit of early detection was maintained beyond 5 years after random assignment, he said.
Of the 161 patients diagnosed with lung cancer, 100 patients died from any cause. There were significantly fewer late-stage lung cancer deaths in the screening arm compared to the control arm. Some 61 percent of the cancers found were diagnosed at Stage I, and possibly curative surgery could be performed for 83 percent of the cancers found, said Field.
Additionally, Field and colleagues included their results in a random-effects meta-analysis to provide a synthesis of the latest randomized trial evidence. This meta-analysis of nine previous randomized controlled trials on LDCT included randomized trials published up to November 2, 2020, with at least 3 years median follow-up. The results of the meta-analysis indicated a significant reduction in lung cancer mortality.
"LDCT screening was associated with a 16 percent relative reduction in lung cancer mortality, when compared against a non-LDCT control arm with no significant heterogeneity," said Field.
In addition, the meta-analysis showed a small reduction in all-cause mortality; he noted that this translates into a large number of lives saved.
"The UKLS mortality data and recent meta-analysis provides the impetus to now put in place long-term lung cancer screening programs internationally, and especially encourage nations in Europe to start their own implementation programs. Lung cancer early detection and surgical intervention saves lives," Field concluded.
Mark L. Fuerst is a contributing writer.