Positron Emission Tomography/Computed Tomography with Gallium-68-labeled Prostate-specific Membrane Antigen Detects Relapse After Vascular-targeted Photodynamic Therapy in a Prostate Cancer Model.
Eur Urol Focus
; 7(2): 472-478, 2021 03.
Article
em En
| MEDLINE
| ID: mdl-31227464
ABSTRACT
BACKGROUND:
Evaluating the efficacy of focal therapy for prostate cancer is limited by current approaches and may be improved with biological imaging techniques.OBJECTIVE:
We assessed whether positron emission tomography/computed tomography with gallium-68-labeled prostate-specific membrane antigen (68Ga-PSMA PET/CT) can be used to predict relapse after vascular-targeted photodynamic therapy (VTP). DESIGN, SETTING, ANDPARTICIPANTS:
A total of 1×106 LNCaP cells were grafted subcutaneously in the flanks of 6-8-wk-old SCID mice. Of 24 mice with measurable tumors 6 wk after tumor implantation, 20 were treated with VTP (150mW/cm2) to ablate the tumors. Blood prostate-specific antigen (PSA) levels were assessed, and 68Ga-PSMA PET/CT images were performed 1 d before VTP and 1 and 4 wk after. OUTCOME MEASUREMENTS AND STATISTICALANALYSIS:
Local tumor relapse was evaluated by histology, and tumors were analyzed by prostate-specific membrane antigen (PSMA) and PSA immunohistochemistry. T tests and Kruskal-Wallis tests were used to determine significance. RESULTS ANDLIMITATIONS:
Four weeks after VTP, 11 (65%) mice had complete responses and six (35%) had tumor relapses confirmed by histology (hematoxylin and eosin, and PSMA immunohistochemistry). All mice with local relapse had positive 68Ga-PSMA PET/CT findings 4 wk after VTP; all complete responders did not. One week after VTP, the relapse detection sensitivity of 68Ga-PSMA PET/CT was 75%, whereas the sensitivity of PSA was only 33%. Compared with controls, relapsed tumors had a three-fold reduction in the number of cells with strong PSA staining by immunohistochemistry (1.5% vs 4.5%; p=0.01).CONCLUSIONS:
In a preclinical prostate cancer model, we show that 68Ga-PSMA PET/CT can identify and predict relapse earlier than blood PSA level. These findings support further testing in clinical trials. PATIENTSUMMARY:
Positron emission tomography/computed tomography with gallium-68-labeled prostate-specific membrane antigen may be used to follow and evaluate treatment outcomes in men who receive focal therapy for prostate cancer.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Próstata
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Neoplasias da Próstata
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Antígeno Prostático Específico
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Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada
/
Radioisótopos de Gálio
Tipo de estudo:
Prognostic_studies
Limite:
Animals
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Humans
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Male
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article