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

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 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.

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.

Our findings support real-world clinical decision-making favoring upfront platinum-based combination therapy for patients with rapidly growing NSCLC.