S763
Clinical - Lung
ESTRO 2026
7 German Cancer Consortium (DTK), partner site Munich, and German Cancer Research Center (DFKZ), Heidelberg, Heidelberg, Germany. 8 Ahmanson Translational Theranostics Division, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Purpose/Objective: Fibroblast activation protein inhibitor (FAPI) targets fibroblast activation protein overexpressed in tumor stroma and captures biological features complementary to glucose metabolism assessed by fluorodeoxyglucose (FDG)-PET. Given its potential advantages in lung cancer detection and staging, this study compared the prognostic performance of baseline [18F]-FDG- and [18F]-FAPI-PET-derived parameters in lung cancer, addressing limited evidence linking FAPI-PET metrics with survival. Material/Methods: Forty consecutive patients with histologically confirmed advanced or recurrent small cell or non- small cell lung cancer underwent [18F]-FDG and [18F]- FAPI-PET/CT before radiotherapy (median interval between scans: 8 days). Semi-quantitative PET/CT parameters included local FDG SUVmax, total and thoracic metabolic tumor volumes (MTVtotal, MTVthoracic), total lesion glycolysis (TLG = SUVmean * MTVthoracic), FAPI SUVmax, FAPI-avid tumor volumes (FTVtotal, FTVthoracic), and total lesion fibroblast activation protein expression (TLF = SUVmean * FTVthoracic). Median dichotomization was performed to establish risk groups. Univariate and multivariate analyses evaluated associations between PET parameters, clinical variables, progression-free survival (PFS), overall survival (OS), locoregional progression-free survival (LRPFS), and distant metastasis-free survival (DMFS). Subgroup analysis included 26 stage III-IV patients receiving definitive thoracic radiotherapy with an equivalent dose in 2-Gy fractions ≥ 54 Gy ( α / β = 10 Gy). Results: After a median follow-up of 18.2 months (range: 1-23), median PFS was 9.3 months (95% CI 7.7–NA), while median OS was not reached. In the definitive-dose subgroup, median PFS was 18 months (95% CI 7.9– NA), median OS was not reached.In univariate analyses, OS was associated with FDG SUVmax (p < 0.006), TLG (p = 0.03), and TLF (p = 0.05). PFS was associated with FDG SUVmax (p = 0.007) and FAPI SUVmax (p = 0.03) (Figure 1), while TLG showed borderline significance (p = 0.06). FDG SUVmax and FAPI SUVmax significantly predicted LRPFS (p = 0.003 and p = 0.05, respectively) and DMFS (p = 0.01 and p = 0.04, respectively). TLG, too, was associated with DMFS (p = 0.04), while TLF trended toward significance (p = 0.08). Subgroup results (n = 26) were consistent. In multivariate analysis, higher FDG SUVmax remained an independent predictor of LRPFS (HR: 5.18, p = 0.04).
33.0 months (95% CI: 29.4–36.6) in the ≥ 70s age group. The median progression-free survival (PFS) was 24.5 months (95%-CI: 19.0-30.0) in the whole cohort and 22.7 months (95%CI: 17.3 – 28.1) for the younger age group versus 29.4 months (95% CI: 20.2 – 38.6) for the older age group. The mean (median not reached) locoregional control (LRC) was 39.0 months (95%-CI: 35.9-42.1) in the entire cohort, 37.8 months (95%-CI: 33.7-41.9) in the younger age group and 34.9 months (95%-CI: 31.4-38.1) in the older age group. The mean (median not reached) local control (LC) was 39.9 months (95%-CI: 36.8-43.0) in all patients, 38.7 months (95%-CI: 34.7-42.7) in the younger age group and 35.7 months (95%-CI: 32.3-39.2) in the older age group. Multivariate analyses revealed that Durvalumab significantly impacted both OS and PFS in the <70s age group (OS p=0.015; PFS p= 0.007) but only PFS in the ≥ 70s age group (p=0.034), whereas sequential chemora-diotherapy improved locoregional (p=0.019) and local control (p=0.006) in the ≥ 70s age group. The Mann-Whitney-U-Test showed no significant difference in toxicity between the two age groups. Conclusion: Durvalumab prolonged progression-free survival regardless of age, while sequentially administered radiotherapy impoved locoregional and local control in patients aged ≥ 70. There was no significant difference in treatment toxicity found between the two age groups. Keywords: Durvalumab, radiation, elderly patients, Prognostic significance of baseline [18F]-FDG vs. [18F]-FAPI PET/CT parameters in advanced and recurrent lung cancer Kira Vordermark 1 , Keywan Assadi 2 , Magdalena A Schöll 2 , Sina Mansoorian 1 , Cedric Richlitzki 1 , Lukas Käsmann 1 , Sophie C Siegmund 2 , Nina-Sophie Schmidt- Hegemann 1 , Niels Reinmuth 3 , Amanda Tufman 4,5 , Marcus Unterrainer 2 , Rudolf A Werner 2,6 , Claus Belka 1,7 , Lena M Unterrainer 2 , Adrien Holzgreve 2,8 , Chukwuka Eze 1,5 1 Department of Radiation Oncology, University Hospital LMU Munich, Munich, Germany. 2 Department of Nuclear Medicine, University Hospital LMU Munich, Poster Discussion 719 Munich, Germany. 3 Department of Oncology, Asklepios Lung Clinic Munich-Gauting, Munich, Germany. 4 Department of Medicine V, University Hospital LMU Munich, Munich, Germany. 5 Comprehensive Pneumology Center Munich (CPC-M), Member of the German Center for Lung Research (DZL), Munich, Germany. 6 The Russell H Morgan Department of Radiology and Radiological Science, Division of Nuclear Medicine and Molecular Imaging, John Hopkins School of Medicine, Baltimore, MD, USA.
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