Carlos Artigas

Paget bone disease demonstrated on 68Ga-PSMA ligand PET/CT

We present the case of an 87-year-old man with a history of prostatic adenocarcinoma diagnosed in 2006 and initially treated locally with high intensity focused ultrasound. An increase of prostate-specific antigen (PSA) values was detected recently and a positron emission/ computed tomography (PET/CT) investigation with the Ga-labelled prostate-specific membrane antigen (PSMA) ligand [Glu-NH-CO-NH-Lys(Ahx)-HBED-CC] was performed at our institution [1]. Apart from focal increased uptake in the prostatic bed, a non-expected overexpression of PSMA was found involving the proximal phalanx of the fourth finger of the left hand (a). On the bone scan performed at the time of initial diagnosis, 9 years ago (b), it appeared that an intense Tc-HDP uptake had already been described in the same location, involving the whole phalanx, with an image suggestive for bone Paget disease (PD) [2]. On physical examination the patient had a swollen and non-painful proximal phalanx with restricted finger motility. A plain X-ray of the hands was performed (c) confirming the diagnosis of monostotic PD of the phalanx [3]. PSMA expression in non-prostatic tumor lesions has already been described and seems to be related to an overexpression of PSMA in the endothelial cells of tumor neovasculature, probably stimulated by secreted angiogenic factors [4, 5]. We hypothesize this mechanism could also be the reason for Ga-PSMA uptake in PD, as it is known to present with an abnormal bone remodeling and increased vascularity. AS bone lesions are the most frequent site of metastatic disease in prostate cancer, it is important to be aware of this possible GaPSMA PET/CT false-positive finding.

Clinical impact of 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in patients with prostate cancer with rising prostate-specific antigen after treatment with curative intent: preliminary analysis of a multidisciplinary approach

To assess the impact of a novel molecular imaging technique, 68Ga‐(HBED‐CC)‐prostate‐specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT), in the clinical management of patients with prostate cancer with rising prostate‐specific antigen (PSA) after treatment with curative intent.

Next revolution in molecular theranostics: personalized medicine for urologic cancers

Extensive lists of molecular biomarkers are currently evaluated as potential targets for directed cancer therapies. We reviewed three potential candidate biomarkers to play a role in the near future as molecular theranostics for urologic malignancies. Carbonic anhydrase type IX is a surrogate marker of hypoxia highly expressed in cancer cells. Their expression and clinical significance in kidney and urothelial bladder cancer are discussed as well as the main therapeutic approaches that are currently under evaluation. For prostate cancer, available evidence on the use of prostate-specific membrane antigen and neuropeptide receptors radiolabeled analog and the undergoing clinical studies are also analyzed and discussed at different stages of prostate cancer.

Vertebral Hemangioma Mimicking Bone Metastasis in 68Ga-PSMA Ligand PET/CT

Ga-PSMA PET/CT was performed in a 68-year-old man to evaluate recurrent prostate cancer due to elevated serum prostate-specific antigen level. Images showed a focal uptake in the prostatic gland, suggesting local relapse, and an intense uptake in the 12th thoracic vertebra, with no morphological abnormalities in CT slices. In order to confirm extraprostatic disease and before radiotherapy planning, a full-spine MRI was performed, resulting with the morphological pattern of a vertebral hemangioma. Hystological analysis confirmed the local relapse in the prostate. No radiotherapy treatment was given to the vertebra, and after 1 year of follow-up without systemic treatment, prostate-specific antigen is still undetectable.

Value of the 68Ga-DOTATATE PET-CT in the diagnosis of endometriosis. A pilot study

OBJECTIVE The non-invasive diagnosis of endometriosis remains challenging. Recent data suggested that somatostatin might be involved in its pathogenesis. High sensitive visualization of somatostatin receptors expression is possible using PET-CT imaging after the administration of a 68Ga-labeled somatostatin analog (DOTATATE) that will bind to the somatostatin receptor sub-types 2 and 5. The aim of the present study was to assess the usefulness of 68Ga-DOTATATE PET-CT in the diagnosis of endometriosis. STUDY DESIGN This is a prospective, single center pilot study. A pre operative 68Ga-DOTATATE PET-CT was performed in all of the patients who presented with suspected endometriosis and who were scheduled for a laparoscopy. Surgical endometriosis staging and histopathological analysis, including somatostatin receptors SST1, 2 and 5 immunohistochemistry (IHC) of removed specimens, were confronted to the results of the 68Ga-DOTATATE PET-CT. RESULTS 12 patients were included in this study. 68Ga-DOTATATE PET-CT performed pre operatively showed increased pathologic uptake in four patients with a deep infiltrating endometriosis (DIE) recto-vaginal lesion and in another patient with an adenomyoma. Expression of SST1, 2 and 5 receptors in surgical specimens was confirmed by IHC in these five lesions. Neither superficial peritoneal endometriosis, nor ovarian endometrioma were found to show an increased pathologic uptake on 68Ga-DOTATATE PET-CT. IHC analysis confirmed that SST1, 2, and 5 receptors were not present in these lesions. CONCLUSION The results observed in this small size series of patients seem to confirm expression of somatostatin receptors only in recto-vaginal DIE and focal adenomyosis lesions. The usefulness of 68Ga-DOTATATE PET-CT in the diagnosis of this entity is uncertain. Future research should concentrate on studying the role of somatostatin in the pathogenesis of DIE.

Prostate-Specific Membrane Antigen-Radioguided Salvage Hemiablation High Intensity Focused Ultrasound for Radio- Recurrent Prostate Cancer

Prostate-specific membrane antigen (PSMA) is a membrane glycoprotein that is a well-characterized and clinically validated marker of prostate cancer (PCa) Gallium 68 (68Ga)–labeled PSMA PET/CT uses the affinity of the 68Ga-labeled PSMA ligand to PSMA expressing cells. Promising results were reported for an accurate staging in patients presenting with biochemical recurrence (BCR) after primary treatment even at low PSA levels. We present the case of a 56 years old patient presenting with a BCR (PSA=21 ng/ml) several years after external radiation beam therapy. Abdominopelvic CT scan and bone scan were negative. A suspicious lesion on PSMA-ligand PET imaging was detected in the prostate with no evidence of regional or distant hypermetabolic lesions