Diagnostic performance of 18F-FDG PET/CT metabolic parameters for early prediction of pathological response in NSCLC treated with neoadjuvant immuno(chemo)therapy: A systematic review and meta-analysis.

[PURPOSE] Early and accurate prediction of pathological response in non-small cell lung cancer (NSCLC) receiving neoadjuvant immune(chemo)immunotherapy is essential for guiding treatment strategies. This meta-analysis aims to assess the predictive performance of PET/CT-derived metabolic parameters for identifying major pathological response (MPR) and pathological complete response (pCR).

[METHODS] The PubMed, Web of Science, Embase, and Cochrane Library were searched for related studies from inception to January 2025. Studies assessed evaluated predefined 18F-FDG PET/CT parameter (PERCIST, PERCIST-max, ΔSUVmax, ΔSULpeak, ΔSULmax, ΔMTV, ΔTLG, pre/post-treatment SUVmax, post-treatment SULmax/SULpeak) and reported pathological outcomes were included. Methodological quality was evaluated using QUADAS-2. Sensitivity, specificity and heterogeneity were analyzed via HSROC models. Publication bias was assessed via Deeks' test.

[RESULTS] Sixteen studies met inclusion criteria. For MPR, PERCIST showed excellent sensitivity (1.00) but limited specificity (0.67), while PERCIST-max achieved both high sensitivity (0.92) and superior specificity (0.94). ΔSUVmax demonstrated balanced accuracy (sensitivity: 0.92; specificity: 0.77; AUC: 0.94), and ΔSULpeak also yielded high diagnostic performance (sensitivity: 0.94; specificity: 0.91). Volumetric metrics such as ΔMTV and ΔTLG showed variable results, with ΔMTV performing moderately (sensitivity: 0.77; specificity: 0.83), and ΔTLG exhibiting lower sensitivity (0.63) despite good specificity (0.81). For pCR, ΔSUVmax retained high sensitivity (0.94) but showed reduced specificity (0.57; AUC: 0.86). SUVmax-Pre showed moderate accuracy (sensitivity: 0.78; specificity: 0.81). Subgroup analyses indicated that the diagnostic performance of ΔSUVmax varied depending on treatment regimen.

[CONCLUSIONS] The study support ΔSUVmax as a reliable indicator of MPR, although its specificity for pCR remains limited. PERCIST's high sensitivity aids in excluding non-responders. However, limited study numbers for parameters like ΔSULpeak, SULpeak-Post, and ΔSULmax reduce generalizability, necessitating larger validation studies to confirm their diagnostic utility.