MONDAY, Dec. 8, 2025 (HealthDay News) -- For patients with extensive-stage small cell lung cancer (ES-SCLC), administration of immune checkpoint inhibitor (ICI) therapy earlier in the day is associated with improved survival, according to a study published online Dec. 8 in Cancer.Zhe Huang, M.D., from the Central South University in Changsha, China, and colleagues conducted a retrospective study to examine the impact of ICI infusion timing in 397 patients with ES-SCLC who received first-line anti-programmed cell death-ligand 1 agents (atezolizumab or durvalumab) plus chemotherapy. The time of day of administration (ToDA) was calculated as the median infusion time for each of the first four ICI treatment cycles. The prognostic relevance was examined by estimating the hazard ratios of earlier progression or death across multiple ToDA thresholds. To balance baseline characteristics, propensity score matching was applied.The researchers found that the optimal ToDA cutoff for maximizing progression-free survival (PFS) benefit was identified as 15:00 hrs, with the lowest hazard ratio seen for PFS at this threshold. Significantly longer PFS and overall survival were seen for patients who received immunochemotherapy before 15:00 hrs compared with those treated later, with consistent results seen across pooled and propensity score-matched cohorts. Early ToDA was confirmed as an independent prognostic factor for both PFS and overall survival (adjusted hazard ratios, 0.483 and 0.373, respectively)."Adjusting infusion timing is a straightforward and easily implementable intervention that can be adopted across diverse health care settings without additional cost," senior author Yongchang Zhang, M.D., also of Central South University, said in a statement.Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter