Lung cancer : journal of the International Association for the Study of Lung Cancer
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Immortal time bias (ITB) can hinder appropriate interpretations of studies administering adjuvant therapies. Given the increase in National Cancer Data Base (NCDB) analyses evaluating postoperative radiation therapy (PORT) as an adjuvant therapy, we sought to practically demonstrate the effects of ITB by performing a series of simulated NCDB analyses. ⋯ Immortal time bias can alter the results of survival analyses if not carefully accounted for. Adjusting for this bias is essential for accurate data interpretation and to better quantify the impact and effect size of adjuvant therapies such as PORT.