Association of metabolic tumour volume (MTV) and total lesion glycolysis (TLG) with survival in patients with oligometastatic non-small-cell lung cancer treated with immunotherapy: a multicentre retrospective study.

PURPOSE Current guidelines recommend adding local radical therapy (LRT) to systemic treatment in synchronous oligometastatic non-small-cell lung cancer (sOM-NSCLC), but survival data on immunotherapy-based regimens are limited. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are prognostic in NSCLC, with higher values linked to worse outcomes. This study examines their association with survival in sOM-NSCLC patients treated with immunotherapy. METHODS We conducted a multicenter retrospective study including all consecutive patients with [18F]FDG-PET and brain imaging-staged sOM-NSCLC, between 2015 and 2022, who received first-line (chemo)-immunotherapy and had baseline PET-scan available for review. Subgroups were analyzed based on median MTV and TLG values (high vs. low: H-MTV vs. L-MTV, H-TLG vs. L-TLG). Study endpoints were progression-free survival (PFS) and overall survival (OS), according to MTV and TLG distribution (high vs. low), in the overall population (primary endpoint) and in relation to LRT and systemic treatment type (secondary endpoints). RESULTS 105 patients were included, 50% were male and 73% had non-squamous histology, median age was 64.9 years. Median PFS was significantly longer for L-MTV vs. H-MTV (14.73 months (95%CI, 7.06-22.40) vs. 7.63 months (95%CI, 5.73-9.52), p = 0.028), but also LRT was associated with PFS (19.04 months (95%CI, 8.47-29.60) versus 7.46 months (95%CI, 5.25-9.67), p = 0.045), while neither MTV nor TLG had impact on OS. In multivariate analysis, only PD-L1 < 50% and soft tissue metastases remained significantly associated with shorter PFS. CONCLUSIONS Baseline MTV is preliminarily associated with PFS in sOM-NSCLC patients treated with immunotherapy, but results are exploratory and need prospective validation in larger cohorts.