Are Longer Telomere Lengths a Risk Factor for Lung Cancer?

Among active or former smokers undergoing lung cancer screening, longer peripheral leukocyte telomere length is associated with an increased risk of lung cancer, independent of emphysema or chronic obstructive pulmonary disease (COPD), according to cross-sectional research published in the European Respiratory Journal.

“Peripheral leukocyte telomere length should be included among the independent factors associated with lung cancer risk,” concluded lead study author Juan P. de-Torres, MD, of the Clinica Universidad de Navarra in Pamplona, Spain, and coauthors.

COPD have been linked to both lung cancer risk and shorter telomere length in previous studies, the authors noted.

In order to determine whether telomere length predicts lung cancer risk independently of COPD status, the authors analyzed data for 250 adults aged 40 years or older, matching patients with and without COPD by age, sex, smoking status and pack-years history, and body mass index (BMI). They found that heavier smoking history, lower BMI, and COPD or medical imaging-detected emphysema were associated with lung cancer in univariate analyses. Patients in the longest telomere-length quartile were at highest risk of having lung cancer.

In multivariate analyses, telomere length, pack-years, and a diagnosis of COPD or radiographic evidence of emphysema each remained “independent predictors” of lung cancer. However, telomere length did not differ significantly between smokers with or without COPD.

The finding is consistent with those of other recent findings linking longer telomere length with lung cancer risk, the authors noted, but the other studies had failed to control for COPD or emphysema status. A separate 2015 report had linked gene variants associated with longer telomeres with lung adenocarcinoma risk.

Because the new study was cross-sectional rather than longitudinal, the authors were unable to offer any causal inferences from their findings, they noted.

However, other studies have suggested that shorter telomere lengths might correlate with survival times among patients with lung cancer, according to a systematic review of seven studies that was separately published in the journal Cancer Epidemiology, Biomarkers & Prevention. Those authors cautioned that despite their potential in lung cancer, telomere lengths and other candidate genomic biomarkers require “larger, carefully designed studies with clinically defined subpopulations and higher-resolution genetic analyses.