Abstract 1789P
Background
The volume of disease (high-volume disease (HVD) / low-volume disease (LVD)) as defined by the CHAARTED criteria based on conventional imaging, is associated with overall survival and used for treatment decisions in mHSPC patients. It remains unknown how the definition of HVD and LVD can be transferred to PSMA-PET imaging.
Methods
In this retrospective study that included 4 international sites, mHSPC patients who underwent a 68Ga-PSMA-11 PET/CT or PET/MRI and a BS (CI) (within a maximum time interval of 100 days) were included. Treatment in between both scans was excluded. HVD and LVD was determined on the BS and on the CT or MRI component. CHAARTED stratification into HVD and LVD was also applied to PSMA-PET. HVD was defined by the presence of visceral metastases and / or > 4 bone metastases (with > 1 beyond spine and pelvis). EXINIboneTM 3.4 (EXINI Diagnostics) was used for the number / localization of bone metastases on BS. The whole-body (WB) PSMA-PET positive tumor volume (PSMA-TV) was obtained using a semi-automatic thresholding method on Affinity 3.0.2 (Hermes Medical Solutions).
Results
Paired PSMA-PET+BS of 50 mHSPC patients were included (median PSA 43.8 (0.2 – 2840.0) ng/ml). 13/50 patients had disease detected in the prostate fossa, 25/50 in lymph nodes, 34/50 in bones and 2/50 in visceral organs by CI and 31/50, 28/50, 29/50 and 2/50 by PSMA-PET, respectively. Based on CI, 14/50 patients had CI-HVD (28%) and 36/50 CI-LVD (72%). Based on PSMA-PET, 21/50 patients had PSMA-HVD (42%) and 22/50 PSMA-LVD (44%). 7/50 (14%) patients had no PSMA-positive lesion or only in the prostate fossa while CI was at least CI-LVD. Overall, mean WB-PSMA-TV was 248.1 ml (0 – 3734.0 ml). In CI-HVD, mean WB PSMA-TV was 713.7 (0.3 – 3734.0) ml, in CI-LVD, 46.4 (0-228.0) ml. In PSMA-HVD, 518.1 (0 – 3734.0) ml and in PSMA-LVD, 59.7 (0 – 228.0) ml. Downstaging from CI to PSMA-PET occurred in in 7/50 patients (14.0%), upstaging (LVD to HVD) in 8/50 patients (16.0%).
Conclusions
Stage migration between LVD and HVD from CI to PSMA PET occurs both by up- and downstaging. Correlation with outcome will lead to new definitions of HVD/LVD based on PSMA PET/CT.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
W. Fendler: Other, Research Funding: SOFIE Bioscience; Other, Other, Consultant, Speaker: Janssen; Other, Other, Constant, image review: Calyx; Other, Other, Consultant, speaker, research funding: Bayer; Other, Other, Consultant, speaker: Novartis; Other, Other, Speaker: Telix; Other, Other, speaker: GE, Eczacıbaşı Monrol. K. Herrmann: Financial Interests, Personal, Advisory Board: Bayer, Adacap/Novartis, Curium, Boston Scientific, GE Healthcare, AstraZeneca; Financial Interests, Personal, Invited Speaker: Sirtex, Siemens Healthineers, Monrol; Financial Interests, Personal, Other, Consultant: Amgen; Financial Interests, Personal, Other, DMSB: ymabs; Financial Interests, Personal, Advisory Board, Scientific Advisor: AdvanceCell; Financial Interests, Personal, Advisory Board, Advisor, Consultant: Janssen; Financial Interests, Personal, Advisory Board, Consultant: Eco1R; Financial Interests, Personal, Member of Board of Directors: Sofie Biosciences, Theragnostics, Pharma 15; Financial Interests, Personal, Ownership Interest: Sofie Biosciences; Financial Interests, Personal, Stocks/Shares: Aktis Oncology; Non-Financial Interests, Leadership Role, Chair Oncology&Theragnostics Committee: EANM. All other authors have declared no conflicts of interest.
Resources from the same session
1219P - Artificial intelligence-based breast cancer detection facilitates automated prognosis marker assessment using multiplex fluorescence immunohistochemistry
Presenter: Tim Mandelkow
Session: Poster session 14
1220P - Comprehensive diagnose of programmed death-ligand 1 from two-dimensional to three-dimensional in breast cancer with computer-aided artificial intelligence system
Presenter: Yi-Hsuan Lee
Session: Poster session 14
1221P - The functional domain of BRCA1/2 pathogenic variants (PVs) as potential biomarkers of second tumor and domain-related sensitivity to PARP-inhibitors
Presenter: Lorena Incorvaia
Session: Poster session 14
1222P - Detection of androgen-receptor splice variant 7 messenger RNA in circulating tumor cells of prostate cancer by in vitro assay
Presenter: Hoin Kang
Session: Poster session 14
1223P - Homologous recombination deficiency (HRD) testing on ovarian cancer ascites: A feasibility study
Presenter: Alberto Ranghiero
Session: Poster session 14
1224P - Detection of circulating tumor DNA (ctDNA) in untreated patients (pts) with cancer: Implications for early cancer detection (ECD)
Presenter: Yoshiaki Nakamura
Session: Poster session 14
1225P - Combining ctDNA and tissue-based-genomic profiling in advanced cancer: A real-world evidence prospective study in non-Western patients treated at Gustave Roussy cancer campus
Presenter: Tony Ibrahim
Session: Poster session 14
1226P - Multi-site validation of a deep learning solution for HER2 profiling of breast cancer from H&E-stained pathology slides
Presenter: Salim Arslan
Session: Poster session 14
1227P - Novel in vivo photonics-immunoassay system, inPROBE, for the rapid detection of HER2 in breast cancer
Presenter: Magdalena Staniszewska
Session: Poster session 14
1228P - A circulating tumor cell (CTC) based assay for diagnostic immunocytochemistry profiling of lung cancer
Presenter: Nitesh Rohatgi
Session: Poster session 14