Ga-FAPI-2/4/46 have already been proposed as promising PET-tracers. However, the short half-life of 68 Ga (T1/2 68 min) creates problems with manufacture and delivery. 18 F (T1/2 110 min) labeling would result in a more practical large scale production and a cold-kit formulation would improve the spontaneous availability. The NOTA-chelator ligand FAPI-74 can be labeled with both 18 F-AlF (Aluminum-Fluoride) and 68 Ga. Here we describe the in-vivo evaluation of 18 F-FAPI-74 and a proof-of-mechanism of 68 Ga-FAPI-74 labeled at ambient temperature. Methods: In ten patients with lung cancer PET-scans were acquired at 10 min, 1h and 3h after administration of 259±26 MBq 18 F-FAPI-74. Physiological biodistribution and tumor uptake were semi-quantitatively evaluated based on SUV at each time-point. Absorbed doses were evaluated using OLINDA/EXM 1.1 and QDOSE dosimetry software with the dose calculator IDAC-Dose 2.1. Identical methods were used to evaluate one exam after injection of 263 MBq 68 Ga-FAPI-74. Results: The highest contrast was achieved 1 h p.i. in primary tumors, lymph node and distant metastases with SUVmax >10, respectively. The effective dose per 100 MBq administered activity of 18 F-FAPI-74 was 1.4±0.2 mSv and for 68 Ga-FAPI-74 it was 1.6 mSv. Thus, the radiation burden of a diagnostic 18 F-FAPI-74 PET-scan is even lower than that of PET-scans with 18 F-FDG and other 18 F-tracers; 68 Ga-FAPI-74 is comparable to other 68 Ga-ligands. FAPI-PET/CT supported target volume definition for guiding radiotherapy. Conclusion: High contrast and low radiation burden of FAPI-74 PET/CT favors multiple clinical applications. Centralized large-scale production of 18 F-FAPI-74 or decentralized cold-kit labeling of 68 Ga-FAPI-74 allows flexible routine use.

BackgroundSystemic inflammation appears to play a role in the progression of numerous solid tumors by promoting tumor proliferation. Our current study aimed to evaluate the role of inflammatory markers in limited disease (LD) small-cell lung cancer (SCLC) patients undergoing thoracic chemoradiotherapy (TCR).Patients and methodsWe retrospectively analyzed a total number of 350 SCLC patients diagnosed with LD SCLC who received TCR between 1999 and 2017 and had available blood tests within 2 weeks prior to the start of TCR. Serum C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), lactate dehydrogenase (LDH), hemoglobin (Hb) levels, and platelet count (Pc) were evaluated as potential inflammatory markers. Kaplan–Meier survival analysis was performed for overall survival (OS). For comparison of survival curves, the log-rank (Mantel–Cox) test was used. Univariate and multivariate Cox proportional HRs were used to assess the influence of cofactors on OS.ResultsUnivariate analysis for OS revealed a statistically significant effect for LDH >400 U/L (HR 2.05 U/L; 95% CI 1.29–3.26 U/L; P=0.002), prophylactic cranial irradiation (PCI; HR 0.58; 95% CI 0.40–0.85; P=0.005), CRP >50 mg/L (HR 1.49 mg/L; 95% CI 1.05–2.10 mg/L; P=0.026), and Karnofsky performance scale (KPS) <70% (HR 1.35%; 95% CI 1.02–1.80%; P=0.035). NLR, age (>70 years), Hb levels, and Pc did not influence survival. In multivariate analysis, OS was significantly affected by PCI (HR 0.64; 95% CI 0.43–0.94; P=0.026), LDH >400 U/L (HR 1.91 U/L; 95% CI 1.21–3.05 U/L; P=0.006), and CRP >50 mg/L (HR 1.43 mg/L; 95% CI 1.01–2.04 mg/L; P=0.045). KPS (≤70%) did not influence survival in multivariate analysis.ConclusionElevated CRP and LDH seem to be the independent prognostic factors for OS in LD SCLC patients undergoing TCR. However, elevated NLR was not found to be an independent prognostic factor for OS if taken prior to TCR. LDH and CRP are easily available blood tests and do not require additional resources for routine use and could be useful for clinical decision making.

Oligoprogression (OPD) of non-small-cell lung cancer (NSCLC) occurs in approximately half of patients under targeted compounds (TKI) and facilitates use of regional therapies that can prolong survival. In order to characterize OPD in immunotherapy (IO)-treated NSCLC, we analyzed the failure pattern under PD-1/PD-L1 inhibitors (n = 297) or chemoimmunotherapy (n = 75). Under IO monotherapy, OPD was more frequent (20% vs. 10%, p < 0.05), occurred later (median 11 vs. 5 months, p < 0.01), affected fewer sites (mean 1.1 vs. 1.5, p < 0.05), and involved fewer lesions (1.4 vs. 2.3, p < 0.05) in the first compared to later lines. Lymph nodes (42%, mainly mediastinal) and the brain (39%) were mostly affected, followed by the lung (24%) and other organs. Compared to multifocal progression, OPD occurred later (11 vs. 4 months, p < 0.001) and was associated with longer survival (26 vs. 13 months, p < 0.001) and higher tumor PD-L1 expression (p < 0.001). Chemoimmunotherapy showed a similar incidence of OPD as IO monotherapy (13% vs. 11% at 2 years). Local treatments were applied regularly for brain but only in 50% for extracranial lesions. Thus, NSCLC oligoprogression is less common under IO than under TKI, but also favorable. Since its frequency drops later in the disease, regular restaging and multidisciplinary evaluation are essential in order to exploit the full therapeutic potential.