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

Methods The clinical and imaging data of 104 patients with advanced NSCLC who received baseline ¹⁸F-FDG PET/CT examination and first-line PD-1 inhibitor combined 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. Among them, there were 93 males and 11 females, with a median age of 64 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 chemotherapy at Zhejiang Cancer Hospital from January 2019 to June 2023 were selected as the validation set for external validation. Among them, there were 21 males and 2 females, with an average age of 64 years. Collect the baseline clinical data of the patients, hematological parameters derived neutrophil-to-lymphocyte ratio (dNLR) and lactate dehydrogenase (LDH) level, and ¹⁸F-FDG PET/CT metabolic parameters maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), tumor metabolic volume (MTV), total glucose metabolism (TLG), whole-body tumor metabolic volume (MTV_wb), and whole-body total glucose metabolism (TLG_wb). The chi-square test was used for the comparison between the two groups of count data. The optimal cut-off values of the above parameters for the training set patients were obtained through receiver operating characteristic (ROC) curve analysis, and all patients were grouped according to the optimal cut-off values. Univariate and multivariate COX proportional hazards regression analyses were used to examine the correlations between the above parameters and progression-free survival (PFS) and overall survival (OS). Draw the Kaplan-Meier survival curves for the PFS and OS of patients in the training set and validation set, and use the Log-Rank test to compare the differences in PFS and OS between the groups of patients.

Results The results of univariate and multivariate COX proportional hazards regression analysis showed that MTV HR=1.810 (1.031~3.178), P=0.039 was an independent predictor of PFS, with the optimal cut-off value being 19.34 cm³; MTV_wb HR=4.112 (2.080~8.129), P<0.001 was an independent predictor of OS, with the optimal cut-off value being 105.79 cm³. There was a statistically significant difference in PFS between the MTV > 19.34 cm³ group and the MTV ≤ 19.34 cm³ group (χ²=4.403, P=0.036). There was also a statistically significant difference in OS between the patients in the MTV_wb > 105.79 cm³ group and those in the MTV_wb ≤ 105.79 cm³ group (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 generalization ability.