MP51-18: Trends of primary staging for newly diagnosed prostate cancer – assessing the uptake of prostate specific membrane antigen positron emission tomography: A population based analysis

Marlon Perera*, Nathan Papa, Declan Murphy, Nathan Lawrentschuk, Melanie Evans, Jeremy Millar, Damien Bolton, Melbourne, Australia

Introduction: Prostate specific membrane antigen (PSMA) positron emission tomography (PET) in advanced prostate cancer imaging demonstrates improved sensitivity and specificity compared to conventional imaging. We aimed to assess prostate cancer staging practice patterns in Victoria, Australia using population-based data.

Methods: We extracted data on men with a tissue diagnosis of prostate cancer between January 2017 and December 2019 from the Victorian Prostate Cancer Outcomes Registry (PCOR-Vic). We evaluated trends and comparisons between patients receiving PET/CT (with or without conventional imaging (CImg)), and CImg alone, and analysed imaging modality as predictor of clinical regional node positive disease (cN1 vs cN0/X), metastatic disease (cM1 vs cM0/X), and treatment received.

Results: In total, 10288 patients in the registry had either a staging PET scan (n = 1599, 16%), CImg without PET scan (n = 3539, 34%), or no recorded PET or CImg (n = 5150, 50%). The proportion of all imaged patients who received staging PET increased from 21% to 39% from the first to last six-month period, and in the patients with grade group =3, the increase was 23-43%. After adjustment for grade group, PET vs CImg-only patients were observed to have a higher proportion of cN1 disease (OR = 2.48, 95% CI: 2.04-3.03) but not cM1 disease (OR = 1.06, 95% CI: 0.87-1.29).

Conclusions: Our registry data highlights the rapid uptake of PET imaging, particularly in higher grade disease. Based on this data, we underline the increased diagnosis of nodal disease, thus potentially optimizing patient selection prior to definitive treatment for prostate cancer.

Source of Funding: Marlon Perera is sponsored by the Australian-America Fulbright Commission administered through a 2021-2022 Fulbright Future Scholarship funded by The Kinghorn Foundation.