Comparison of Bone Uptake in Bone Scan and Ga-68 PSMA PET/CT Images in Patients with Prostate Cancer

Abstract

Objective: The aim of this study was to compare images from Tc-99m MDP bone scan (BS) and Ga-68 PSMA PET/CT of patients with prostate cancer in terms of bone metastases. Methods: Overall, 34 patients exhibited a mean age of 66 ± 9.5 (50-88) years, mean PSA of 51 ± 159ng/ml (0-912), and mean Gleason score of 8 (6-9). BS and Ga-68 PSMA PET/CT were applied to 34 patients within 30 days, and the results were evaluated, retrospectively. In both tests, radiopharmaceutical uptake in bones were compared. Results: In 7 patients (20.5%), uptake was not significant on BS and Ga-68 PSMA PET / CT images, which is related to metastasis. In 14 (41%) patients, bone metastases were observed in both examinations. However, more metastatic lesions were observed in the Ga-68 PSMA PET/CT of 3 patients and in the bone scintigraphy of 2 patients. PSMA expression was not observed on Ga-68 PSMA PET / CT in 13 (38%) patients with increased activity in bone scintigraphy. Two (6%) of these patients were thought to be metastatic, 2 (6%) were suspicious for metastasis, and 9 (26%) had no metastasis. When a lesion-based evaluation was performed, a total of 480 activities were evaluated: increased activity uptake was found in 305 BS, and 427 PSMA expression activity was detected. Furthermore, 435 of these activities were evaluated as metastatic. Conclusion: Ga-68 PSMA PET/CT provides an additional contribution to the BS evaluation of activity areas because of the presence of PSMA expression and anatomical lesions. In 6% of the patients, activity on BS and metastatic appearance in CT images were observed and the presence of lesions in the absence of PSMA was determined. This suggests that bone metastases without PSMA expression may also be present.

DOTA Conjugate of Bisphosphonate and PSMA-Inhibitor: A Promising Combination for Therapy of Prostate Cancer Related Bone Metastases

“…Prostate cancer can vary widely in the expression of PSMA. It is known that primary tumors and especially metastases can be PSMA-negative (34)(35)(36)(37)(38). This can also be the case for bone metastases (36,37).…”

“…It is known that primary tumors and especially metastases can be PSMA-negative (34)(35)(36)(37)(38). This can also be the case for bone metastases (36,37). Here, it was shown that there is a high correlation between bone metabolic activity and cancer-related PSMA expression in bone lesions at early stages of the disease, implying that bone metastases have significantly higher PSMA expression at early stages.…”

Experience with the Preparation of ⁶⁸Ga-PSMA-11

“…Nejčastěji jsou inhibitory PSMA značeny izotopem gallia-68. Diagnostických uplatnění inhibitorů značených galliem-68 je popsáno již poměrně hodně, kromě karcinomu prostaty [4][5][6][7] také např. pro hepatocelulární karcinom 8,9 , gliomy 10 , karcinom prsu 11 , karcinom pankreatu 12 a další.…”

Incorporating PSMA-Targeting Theranostics Into Personalized Prostate Cancer Treatment: a Multidisciplinary Perspective

“…At the time of writing, two of these agents, 68 Ga-PSMA-11 and 18 F-DCFPyL, have been FDA-approved (but awaiting CMS approval). Beyond favorable imaging profiles ( 20 ), these agents have been demonstrated in multiple retrospective and prospective studies to be superior compared to standard cross-sectional imaging, (CT/MRI) ( 21 , 22 ) nuclear medicine assays (bone scintigraphy) ( 23 , 24 ), 18 F-fluciclovine ( 25 – 29 ), 11 C-choline PET/CT ( 30 , 31 ), and other modalities ( 32 , 33 ) for characterizing disease burden across the spectrum of the disease ( Figure 1 ). Applications include the localized disease setting for both intraprostatic localization and staging ( 34 – 36 ), detection of lesions during biochemical recurrence ( 22 , 37 ), and for stratification and treatment monitoring in metastatic disease ( 38 ).…”