Non-small cell lung cancer (NSCLC) survivors who never smoked or who are former smokers at the time of diagnosis have a lower risk of developing secondary primary lung cancers (SPLC) compared to those who are current smokers.

This suggests that increased tobacco exposure is associated with a higher risk of SPLC, according to research presented today at the American Society for Radiation Oncology’s (ASTRO’s) 56th Annual Meeting.

The analysis studied the association between patients’ smoking histories and their risks of developing SPLC, which is defined as a new lung cancer unrelated to the initial tumor based on histology and location in the lung.

The study found that five years after the initial diagnosis, current smokers were more likely to develop SPLC. The five-year incidence of SPLC was 13% for current smokers, 7% for former smokers, and 0% for patients who had never smoked.