Restaging scans frequency heterogeneity in patients being treated for stage IV non-small cell lung cancer (NSCLC)

e21161 Background: Patients with stage IV NSCLC undergo frequent restaging scans (RS). While vital to assess treatment response, RS add anxiety and financial burdens to patients. The ideal frequency of RS is unclear. The numerous treatment options available, such as targeted therapy (TT) and immunotherapy (IO), and the variability in frequency of RS in the trials that led to their approval reflect this uncertainty. Due to the lack of clear guidelines about their ideal interval in daily practice, we reviewed the heterogeneity in frequency of RS in those trials, comparing it to the reported progression-free survival (PFS). Methods: In this study, we reviewed the FDA-approved drugs for stage IV NSCLC since 10/18/2016 and selected the TT and IO. Each trial that led to approval was reviewed, collecting the frequency of RS and the median PFS for the intervention (IA) and control arms (CA). Results: 18 TT drugs and 12 IO regimens, with and without chemotherapy (chemo), were found. Among them, the frequency of RS varied from every 4 to 9 weeks (w) upfront, later modified to every 6 to 12 w until disease progression. The median PFS for both groups in the IA ranged from 2.8 to 19.4 months (m), and from 3.0 to 12.4 m in the CA. The TT group had drugs directed at 7 different mutations, and it presented more discrepancy in terms of restaging frequency. The period between RS varied from every 4 to 8 w initially, later modified to every 6 to 12 w. However, 11 of 18 trials had an interval of every 6 w. The shortest median PFS in the IA arm was 5.4 m, and 5.6 m in the CA. While the longest median PFS was 19.4 m in the IA and 12.4 m in the CA. The IO group included 5 regimens with chemo and 7 without. The interval between RS varied from 6 to 9 w originally, to every 8 to 12 w later. Yet, 8 of 12 regimens’ trials scanned patients every 6 w initially. The median PFS in the IA ranged from 2.8 to 10.3 m, and between 3.0 to 6.5 m in the CA. Conclusions: We observed notable heterogeneity among trials regarding the frequency of RS in patients treated for stage IV NSCLC. When comparing these intervals to the median PFS, we noted the shortest PFS reported is longer than most adopted intervals. This may indicate RS were obtained more frequently than needed. The increased frequency of RS raises a burden for patients and the medical system, while contributing to disparities. This finding, coupled with further comparisons between the frequency of RS in trials and in daily practice, may pave the way for prospective studies analyzing the ideal interval for RS. This can lead to a more efficacious and less burdensome strategy for patients. [Table: see text]