Pretreatment Tumor Growth Rate and Clinical Outcomes in Advanced Non–small Cell Lung Cancer

Background/Aim: Immune checkpoint inhibitors (ICIs) have improved clinical outcomes in patients with non-small cell lung cancer (NSCLC); however, treatment responses vary across individuals. While pretreatment tumor growth dynamics may reflect the disease’s clinical aggressiveness, the impact of rapid tumor growth before treatment initiation on therapeutic decision-making and prognosis is unclear. This study aimed to clarify the associations between pretreatment tumor growth rate (TGR), treatment selection, and survival outcomes. Patients and Methods: Patients with NSCLC who received ICIs and underwent two radiologic assessments at initial presentation and immediately before treatment initiation were retrospectively enrolled. Based on the TGR, patients were classified into a TGR-positive group (TGR ≥1.0% per 30 days) and a TGR-negative group (TGR <1.0% per 30 days). Associations between TGR status and clinical characteristics, treatment selection, and survival outcomes were evaluated. Results: Patients in the TGR-positive group had larger baseline tumor diameters with a greater prevalence of high programmed death-ligand 1 (PD-L1) expression. Among patients with high PD-L1 expression, those in the TGR-positive group were more likely to receive ICI-based combination therapy, including platinum chemotherapy, than ICI monotherapy. Although progression-free survival (PFS) or overall survival (OS) did not differ in dichotomized analyses, multivariate Cox regression analyses demonstrated a borderline association between TGR and OS. Neutrophil-to-lymphocyte ratio was independently associated with both PFS and OS. Platinum-based combination therapy was independently associated with prolonged PFS. Conclusion: Our findings support real-world clinical decision-making favoring upfront platinum-based combination therapy for patients with rapidly growing NSCLC.