Exploring New Multimodal Quantitative Imaging Indices for the Assessment of Osseous Tumor Burden in Prostate Cancer Using Ga-PSMA PET/CT

TY - JOUR

T1 - Exploring New Multimodal Quantitative Imaging Indices for the Assessment of Osseous Tumor Burden in Prostate Cancer Using Ga-PSMA PET/CT

AU - Bieth, Marie

AU - Krönke, Markus

AU - Tauber, Robert

AU - Dahlbender, Marielena

AU - Retz, Margitta

AU - Nekolla, Stephan G

AU - Menze, Bjoern

AU - Maurer, Tobias

AU - Eiber, Matthias

AU - Schwaiger, Markus

N1 - © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

PY - 2017/10

Y1 - 2017/10

N2 - PET combined with CT and prostate-specific membrane antigen (PSMA) ligands has gained significant interest for staging prostate cancer (PC). In this study, we propose 2 multimodal quantitative indices as imaging biomarkers for the assessment of osseous tumor burden using 68Ga-PSMA PET/CT and present preliminary clinical data. Methods: We defined 2 bone PET indices (BPIs) that incorporate anatomic information from CT and functional information from 68Ga-PSMA PET: BPIVOL is the percentage of bone volume affected by tumor and BPISUV additionally considers the level of PSMA expression. We describe a semiautomatic computation method based on segmentation of bones in CT and of lesions in PET. Data from 45 patients with castration-resistant PC and bone metastases during 223Ra-dichloride were retrospectively analyzed. We evaluated the computational stability and reproducibility of the proposed indices and explored their relation to the prostate-specific antigen blood value, the bone scan index (BSI), and disease classification using PERCIST. Results: On the technical side, BPIVOL and BPISUV showed an interobserver maximum difference of 3.5%, and their computation took only a few minutes. On the clinical side, BPIVOL and BPISUV showed significant correlations with BSI (r = 0.76 and 0.74, respectively, P < 0.001) and prostate-specific antigen values (r = 0.57 and 0.54, respectively, P < 0.01). When the proposed indices were compared against expert rating using PERCIST, BPIVOL and BPISUV showed better agreement than BSI, indicating their potential for objective response evaluation. Conclusion: We propose the evaluation of BPIVOL and BPISUV as imaging biomarkers for 68Ga-PSMA PET/CT in a prospective study exploring their potential for outcome prediction in patients with bone metastases from PC.

AB - PET combined with CT and prostate-specific membrane antigen (PSMA) ligands has gained significant interest for staging prostate cancer (PC). In this study, we propose 2 multimodal quantitative indices as imaging biomarkers for the assessment of osseous tumor burden using 68Ga-PSMA PET/CT and present preliminary clinical data. Methods: We defined 2 bone PET indices (BPIs) that incorporate anatomic information from CT and functional information from 68Ga-PSMA PET: BPIVOL is the percentage of bone volume affected by tumor and BPISUV additionally considers the level of PSMA expression. We describe a semiautomatic computation method based on segmentation of bones in CT and of lesions in PET. Data from 45 patients with castration-resistant PC and bone metastases during 223Ra-dichloride were retrospectively analyzed. We evaluated the computational stability and reproducibility of the proposed indices and explored their relation to the prostate-specific antigen blood value, the bone scan index (BSI), and disease classification using PERCIST. Results: On the technical side, BPIVOL and BPISUV showed an interobserver maximum difference of 3.5%, and their computation took only a few minutes. On the clinical side, BPIVOL and BPISUV showed significant correlations with BSI (r = 0.76 and 0.74, respectively, P < 0.001) and prostate-specific antigen values (r = 0.57 and 0.54, respectively, P < 0.01). When the proposed indices were compared against expert rating using PERCIST, BPIVOL and BPISUV showed better agreement than BSI, indicating their potential for objective response evaluation. Conclusion: We propose the evaluation of BPIVOL and BPISUV as imaging biomarkers for 68Ga-PSMA PET/CT in a prospective study exploring their potential for outcome prediction in patients with bone metastases from PC.

KW - Antigens, Surface

KW - Bone Neoplasms

KW - Gallium Radioisotopes

KW - Glutamate Carboxypeptidase II

KW - Humans

KW - Male

KW - Positron Emission Tomography Computed Tomography

KW - Prostatic Neoplasms, Castration-Resistant

KW - Retrospective Studies

KW - Tumor Burden

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.2967/jnumed.116.189050

DO - 10.2967/jnumed.116.189050

M3 - SCORING: Journal article

C2 - 28546330

VL - 58

SP - 1632

EP - 1637

JO - J NUCL MED

JF - J NUCL MED

SN - 0161-5505

IS - 10

ER -