Lung cancer screening significantly reduces mortality, meta-analysis shows
Patients who underwent lung cancer screening had a significant reduction in mortality associated with the disease, although it came with a “tradeoff” of likely overdiagnosis, according to a recent meta-analysis.
“We saw that all-cause and disease-specific mortality went in the same direction, which suggests that there is a net benefit” to lung cancer screening, Mark H. Ebell, MD, MS, professor of epidemiology and biostatistics at the University of Georgia College of Public Health, told Healio Primary Care.
Ebell and colleagues analyzed eight trials of low-dose CT that had a low risk for bias, including a total of 90,475 patients aged 49 to 75 years. The patients were followed for a median of 5.2 to 10 years. Two of the trials — the National Lung Screening Trial and its pilot study — used chest radiography as the comparator, whereas the remaining trials used usual care. All but one trial took place in Europe.
“I do not see important differences between European and United States populations, and the primary risk factor is smoking, not sex,” Ebell said. “The European studies are totally relevant to the United States.”
Results from the study, published in Annals of Family Medicine, showed a significant reduction in lung cancer-specific mortality with low-dose CT screening (RR = 0.81; 95% CI, 0.74-0.89), and the estimated absolute risk reduction was 0.4%. According to the researchers, the number needed to screen to prevent one lung cancer death was 250. Although the reduction in all-cause mortality was not statistically significant (RR = 0.96; 95% CI, 0.92-1.01), the absolute risk reduction was consistent with that for lung cancer-specific mortality, at 0.34%. The number needed to screen to prevent one death from any cause was 294, the researchers said.
In the five studies that followed patients for at least 8 years, the incidence of lung cancer was 25% higher in the screened group, corresponding with a 20% rate of overdiagnosis. According to Ebell and colleagues, these rates are consistent with estimates from other studies of lung cancer diagnosis and breast cancer overdiagnoses.
Ebell and colleagues said that lung cancer screening in the U.S. has had “a very low uptake.”
“Measures to increase uptake of lung cancer screening and ensure adherence to follow-up protocols based on the best available evidence are needed,” they wrote.