CT screening appears to reduce lung cancer mortality in high-risk patients

Patients who are at high risk for lung cancer may benefit from periodic CT screening, according to a recent randomized trial.

Researchers in Belgium and the Netherlands randomly assigned 13,195 men and 2,594 women ages 50 to 74 years to undergo four rounds of low-dose CT screening (baseline, year 1, year 2, and year 2.5) or no screening. The primary analysis was done in men, and subgroup analyses were done in women. Data on cancer diagnosis and date and cause of death were obtained through national registries. A clinical expert committee determined whether deaths were attributed to lung cancer.

All participants were followed for a minimum of 10 years until Dec. 31, 2015, and lung cancer mortality was compared between the screening group and the control group. Results were published Jan. 29 by the New England Journal of Medicine.

Overall, 6,583 men were assigned to the screening group and 6,612 were assigned to the no-screening group. Average adherence to CT screening among men was 90.0%. An average of 9.2% of CT scans (2,069 of 22,600) required a least one additional CT scan. Overall referral rate was 2.1% for suspicious nodules, with 203 screening-detected cases of lung cancer diagnosed.

At 10-year follow-up, lung cancer incidence was 5.58 cases per 1,000 person-years in the screening group and 4.91 cases per 1,000 person-years in the control group, while lung cancer mortality was 2.50 deaths per 1,000 person-years and 3.30 deaths per 1,000 person-years, respectively. The cumulative rate ratio for death from lung cancer was 0.76 (95% CI, 0.61 to 0.94; P=0.01) at 10 years in the screening group versus the control group for men, with similar rate ratios seen at years 8, 9, and 11.

For women randomized to screening, the cumulative rate ratio for death from lung cancer was 0.67 (95% CI, 0.38 to 1.14) at 10 years, 0.52 (95% CI, 0.28 to 0.94) at 9 years, 0.41 (95% CI, 0.19 to 0.84) at 8 years, and 0.46 (95% CI, 0.21 to 0.96) at 7 years.

Authors noted that their results suggested more benefit in women than in men, although the number of women in the trial was smaller. They called for additional research in women and in other subgroups.

An accompanying editorial said that the current trial confirms the efficacy of periodic low-dose CT screening in reducing mortality from lung cancer and that determining cost-effectiveness is the next step. This will depend on the interval between screenings as well as the population targeted, the editorialists said.

“Our job is no longer to assess whether low-dose CT screening for lung cancer works; it does,” they wrote. “Our job is to identify the target population in which it will be acceptable and cost-effective.”