Combined biology-guided radiotherapy and Lutetium PSMA theranostics treatment in metastatic castrate-resistant prostate cancer

Frontiers in Oncology

Oncology

Price Jackson¹  Mathieu Gaudreault¹  Tomas Kron²  Nicholas Hardcastle²  Shankar Siva³  David Chang³  Michael S. Hofman⁴ 

[1] Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia;Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC, Australia;Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia;Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC, Australia;Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia;Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC, Australia;Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia;Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC, Australia;Molecular Imaging and Therapeutic Nuclear Medicine, Cancer Imaging, Prostate Cancer Theranostics and Imaging Centre of Excellence (ProsTIC), Peter MacCallum Cancer Centre, Melbourne, VIC, Australia;

关键词: BgRT;    LuPSMA;    theranostics;    mCRPC;    PSMA;   

DOI  :  10.3389/fonc.2023.1134884

 received in 2022-12-31, accepted in 2023-02-13,  发布年份 2023

来源: Frontiers

【 摘 要 】

BackgroundLutetium-177 [177Lu]-PSMA-617 is a targeted radioligand that binds to prostate-specific membrane antigen (PSMA) and delivers radiation to metastatic prostate cancer. The presence of PSMA-negative/FDG-positive metastases can preclude patients from being eligible for this treatment. Biology-guided radiotherapy (BgRT) is a treatment modality that utilises tumour PET emissions to guide external beam radiotherapy. The feasibility of combining BgRT and Lutetium-177 [177Lu]-PSMA-617 for patients with PSMA-negative/FDG-positive metastatic prostate cancer was explored.Materials and methodsAll patients excluded from the LuPSMA clinical trial (ID: ANZCTR12615000912583) due to PSMA/FDG discordance were retrospectively reviewed. A hypothetical workflow where PSMA-negative/FDG-positive metastases would be treated with BgRT whilst PSMA-positive metastases would be treated with Lutetium-177 [177Lu]-PSMA-617 was considered. Gross tumour volume (GTV) of PSMA-negative/FDG-positive tumours were delineated on the CT component of the FDG PET/CT scan. Tumours were deemed suitable for BgRT if (1) normalised SUV (nSUV), defined as the ratio of maximum SUV (SUVmax) inside the GTV to mean SUV inside a 5 mm/10 mm/20 mm margin expansion of the GTV, was larger than a pre-specified nSUV threshold and (2) there was no PET avidity inside the margin expansion.ResultsIn 75 patients screened for Lutetium-177 [177Lu]-PSMA-617 treatment, 6 patients were excluded due to PSMA/FDG discordance and 89 PSMA-negative/FDG-positive targets were identified. GTV volumes ranged from 0.3 cm3 to 186 cm3 (median GTV volume = 4.3 cm3, IQR = 2.2 cm3 – 7.4 cm3). SUVmax inside GTVs ranged between 3 and 12 (median SUVmax = 4.8, IQR = 3.9 – 6.2). With nSUV ≥ 3, 67%/54%/39% of all GTVs were suitable for BgRT within 5 mm/10 mm/20 mm from the tumour. Bone and lung metastases were the best candidates for BgRT (40%/27% of all tumours suitable for BgRT with nSUV ≥ 3 within 5 mm from the GTV were bone/lung GTVs).ConclusionsCombined BgRT/Lutetium-177 [177Lu]-PSMA-617 therapy is feasible for patients with PSMA/FDG discordant metastases.

【 授权许可】

Unknown   
Copyright © 2023 Gaudreault, Chang, Hardcastle, Jackson, Kron, Hofman and Siva