Quantitative [18F]PSMA-1007 PET in Treatment Response Monitoring of Brain Metastases from Non-small Cell Lung Cancer
摘要
Prostate-specific membrane antigen (PSMA) is expressed in several solid tumours, including brain metastases (BMs) from lung cancer. We investigated quantitative [18F]PSMA-1007 uptake and treatment response in BMs of patients with non-small cell lung cancer (NSCLC).
ProceduresEleven patients with BM of NSCLC underwent 95-min dual-time-point dynamic [18F]PSMA-1007 PET/CT and a whole-body static scan before and after stereotactic radiosurgery (SRS) with a median dose of 20 Gy (range: 8–25 Gy) given in a median of 1 fraction (range: 1–3). Seven patients completed both exams. Image-derived input functions were extracted from the internal carotid arteries, and pharmacokinetic analysis using Patlak modelling yielded the influx constant (Ki). Standardised uptake value (SUV), biological tumour volume (BTV) and tumour heterogeneity using the coefficient of variance (CoV) were assessed.
Results[18F]PSMA-1007 PET showed uptake in the first exam in BMs and primary lung tumour in all patients. Significant inter-patient and intra-lesion heterogeneity in tracer uptake was observed in BMs with median Ki of 0.005 ml/ccm/min (range: 0.003–0.018 ml/ccm/min), SUVpeak of 4.2 g/ml (range: 0.4–34.4 g/ml), CoV of 0.36 (range 0.06–0.85) and BTV of 2.35 ml (range 0.03–22.29 ml). After SRS, reductions in Ki (37%), SUVpeak (50%), CoV (24%) and BTV (71%) were noted. Median SUVpeak in the lungs were 6.1 g/ml (range: 3.2–13.6 g/ml) at the initial exam and 6.3 g/ml (range: 3.8–11.8 g/ml) at the second exam.
Conclusion[18F]PSMA-1007 PET is a promising diagnostic tool for BMs from NSCLC. The uptake and heterogeneity, along with the marked reduction post-therapy, highlights its potential for monitoring treatment response.
Trial registrationClinicaltrials.gov, NCT03951142. Registered 5 October 2019, https://clinicaltrials.gov/ct2/show/NCT03951142. EudraCT no 2018-003229-27. Registered 26 February 2019, https://www.clinicaltrialsregister.eu/ctr-search/trial/2018-003229-27/NO.