Objective To discuss the predictive value of baseline ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in the prognosis of patients with advanced non-small cell lung cancer (NSCLC) treated with programmed death-1 (PD-1) inhibitor combined with chemotherapy.

Methods The clinical and imaging data of 104 patients with advanced NSCLC who underwent baseline ¹⁸F-FDG PET/CT examinations and first-line PD-1 inhibitor combined with chemotherapy at Tianjin Medical University Cancer Institute and Hospital from January 2018 to June 2023 were selected as the training set for a retrospective cohort study. The training set comprised 93 males and 11 females, with a median age of 64 years, ranging from 28 to 79 years. The clinical and imaging data of 23 patients with advanced NSCLC who received baseline ¹⁸F-FDG PET/CT examination and first-line PD-1 inhibitor combined with chemotherapy at Zhejiang Cancer Hospital from January 2019 to June 2023 were selected as the validation set for external validation. The validation set comprised 21 males and 2 females, with an average age of 64 years, ranging from 52 to 81 years. Collect the baseline clinical data, hematological parameters, and ¹⁸F-FDG PET/CT metabolic parameters of patients. The optimal cut-off values of the above parameters in the training set patients were obtained through receiver operating characteristic curve analysis, and all patients were grouped according to the optimal cut-off values. Univariate and multivariate Cox proportional hazards regression analyses were performed to examine the correlations between the above parameters and progression-free survival (PFS) and overall survival (OS). Plot the Kaplan-Meier survival curves for the PFS and OS of patients in the training and validation sets and perform the Log-rank test to compare the differences in PFS and OS between groups of patients.

Results The results of univariate and multivariate Cox proportional hazards regression analyses showed that metabolic tumor volume (MTV) (HR=1.810 (95%CI: 1.031–3.178), P=0.039) was an independent predictor of PFS, with the optimal cut-off value of 19.34 cm³; metabolic tumor volume of whole body (MTV_wb) (HR=4.112 (95%CI: 2.080–8.129), P<0.001) was an independent predictor of OS, with the optimal cut-off of 105.79 cm³. A statistically significant difference in PFS was observed between patients in the MTV>19.34 cm³ group and those in the MTV≤19.34 cm³ group of validation set (χ²=4.403, P=0.036). A statistically significant difference in OS was observed between patients in the MTV_wb>105.79 cm³ group and those in the MTV_wb≤105.79 cm³ group of validation set (χ²=4.207, P=0.040).

Conclusion Baseline ¹⁸F-FDG PET/CT can effectively predict the prognosis of patients with advanced NSCLC who receive first-line PD-1 inhibitor combined with chemotherapy, and it has certain accuracy and generalizability.