NELSON trial confirms overwhelming benefits of CT lung cancer screening

New results from the Dutch-Belgian Randomized Lung Cancer Screening Trial, or NELSON trial, reaffirms that widespread CT lung cancer screening could significantly reduce mortality rates. The findings were published Jan. 29 in the New England Journal of Medicine.

Investigators analyzed the impact of low-dose CT screening among more than 15,000 individuals across a 10-year follow-up period. They determined that total lung cancer deaths fell by about 33% in women and 24% in men, compared to patients who did not undergo screening.

With estimates from the American Cancer Society, implementing such widespread screening could save between 30,000 and 60,000 lives in the U.S. each year.

“Lung cancer kills more people each year than breast, colon and prostate cancers combined. If implemented nationwide, this cost-effective test would save more lives than any cancer screening test in history,” Debra Dyer, MD, chair of the American College of Radiology Lung Cancer Screening 2.0 Committee said in a statement. “Medicare must provide adequate reimbursement for these exams.”

Initial results from this trial estimated that low-dose CT screening in high-risk patients reduced lung cancer deaths by 26% in men, and up to 61% in women. Those results, first presented at the 2018 International Association for the Study of Lung Cancer World Conference in Toronto, also revealed a 44% reduction in overall deaths if male and female participants were split evenly.

In the United States, low-dose CT screening has been adopted as policy since the first results of the National Lung Screening Trial showed a 20% reduction in lung cancer mortality as a result of the intervention. However, Europe and other regions have been slow to follow-suit, hung up on inconclusive results from smaller trials and concerns regarding overdiagnosis. But these lingering questions should now be laid to rest, argued Stephen W. Duffy, of Queen Mary University of London, and John K. Field, PhD, with the University of Liverpool.

“With the NELSON results, the efficacy of low-dose CT screening for lung cancer is confirmed,” the pair wrote Jan. 29, in an accompanying editorial. “Our job is no longer to assess whether low-dose CT screening for lung cancer works: it does. Our job is to identify the target population in which it will be acceptable and cost-effective.”

The NELSON trial randomized 13,195 men and 2,594 women between age 50 and 74 to undergo CT screening at the onset of the study, and at 1 year, 3 year and 5 year intervals, or no screening at all. The trial, initiated in 2000, completed a minimum of 10 year follow-up in all participants, concluding in December 2015.

After analysis, patients in the screening arm showed a higher incidence of cancer, 5.58 cases versus 4.91 per 1000 person-years. Those who received low-dose CT screening had lower mortality rates: 2.5 deaths compared to 3.3 deaths per 1,000 person-years.

The results also confirm initial reports from the trial showing a 25% reduction in the risk of lung cancer death in those who receive screening.

Additionally, the editorialists noted that the trial yielded an overdiagnosis rate of about 10%, “at worst.” An acceptable figure given the reduction in mortality, they added.

With the benefits of low-dose CT screening now clearly proven, Duffy and Field, believe the next task will be determining the cost-effectiveness of this strategy.

“The massive lifesaving benefit of these exams, and the threat to older current and former smokers from this disease, outweighs any potential harms to the defined screening population,” Dyer said. “We must do all we can to ensure patients are appropriately referred and have widespread access to lung cancer screening CT.”