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Purpose: The current clinical recommendations posit the deployment of specific approved radiolabeled prostate-specific membrane antigen-ligand positron emission tomography (PSMA PET) for detecting metastatic prostate cancer during primary staging. Nevertheless, the precise efficacy of such ligands in localizing intraprostatic tumours (index tumour) and T-staging is not well established. Consequently, the objective of this inquiry is to ascertain the diagnostic accuracy of PSMA-PET in the tumour staging of newly diagnosed prostate cancer by means of a meta-analysis that integrates studies utilizing histological confirmation as the reference standard., Methods: In this study, we conducted a systematic literature search of the PubMed, Embase, Web of Science, and Cochrane Library databases using a predefined collection of search terms. These terms included 'PSMA PET', 'primary staging', and 'prostate cancer'. Subsequently, two independent reviewers evaluated all the studies based on predetermined inclusion criteria, extracted pertinent data, and assessed the quality of evidence. Any disparities were resolved by a third reviewer. A random effects Sidik-Jonkman model was applied to conduct a meta-analysis and estimate the diagnostic accuracy on a per-patient basis, along with 95% confidence intervals. Moreover, an appraisal regarding the likelihood of publication bias and the impact of small-study effects was performed utilizing both Egger's test and a graphical examination of the funnel plot., Results: The present analysis comprised a total of twenty-three scientific papers encompassing 969 patients and involved their analysis by both qualitative and quantitative approaches. The results of this study demonstrated that the estimated diagnostic accuracy of PSMA PET/CT and PSMA PET/MRI, for the detection of intraprostatic tumours, regardless of the type of PSMA-ligand, was 86% (95% CI: 76-96%) and 97% (95% CI: 94-100%), respectively. Furthermore, the diagnostic accuracy for the detection of extraprostatic extension (EPE) was 73% (95% CI: 64-82%) and 77% (95% CI: 69-85%), while the diagnostic accuracy for the detection of seminal vesicle involvement (SVI) was 87% (95% CI: 80-93) and 90% (95% CI: 82-99%), respectively., Conclusion: The present investigation has demonstrated that PSMA PET/MRI surpasses currently recommended multiparametric magnetic resonance imaging (mpMRI) in terms of diagnostic accuracy as inferred from a notable data trajectory, whereas PSMA-PET/CT exhibited comparable diagnostic accuracy for intraprostatic tumour detection and T-staging compared to mpMRI. Nevertheless, the analysis has identified certain potential limitations, such as small-study effects and a potential for publication bias, which may impact the overall conclusions drawn from this study., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A 70-year-old man with high-risk prostate cancer (PCa) received radiation therapy and androgen deprivation therapy (ADT). The patient developed penile tenderness, compatible with Peyronie's disease upon physical examination. An ultrasound revealed a matching hypoechoic plaque and a thrombus in the vena dorsalis profunda, which were treated with anticoagulants. A follow-up ultrasound showed no abnormalities. Despite the use of analgesics, the patient suffered from persistent pain, later accompanied by an increasing PSA level of up to 7.5 ng/mL, despite ADT. 68 Ga-PSMA PET/CT showed a PSMA uptake consistent with PCa penile metastasis. Due to severe pain and the presence of metastatic PCa, the patient was referred for penectomy. Histopathological analysis confirmed metastases originating from the PCa. This case underscores the importance of 68 Ga-PSMA PET/CT in diagnosing PCa metastases and vigilance towards urogenital symptoms as potential indicators of metastases, despite the rarity of penile metastases.

A 78-year-old man with newly diagnosed high-risk prostate cancer underwent 68 Ga-PSMA PET/CT for primary staging. This showed a single, very intense PSMA uptake in the vertebral body of Th2, without discrete morphological changes on low-dose CT. Thus, the patient was considered oligometastatic and underwent MRI of the spine for stereotactic radiotherapy planning. MRI demonstrated an atypical hemangioma in Th2. A bone algorithm CT scan confirmed the MRI findings. The treatment was changed, and the patient underwent a prostatectomy with no concomitant therapy. At three and six months after the prostatectomy, the patient had an unmeasurable PSA level, confirming the benign etiology of the lesion.

Objective: Gallium-68-DOTA-D-Phe1-Try3-Octreotide ( 68 Ga-DOTATOC) is a radiolabeled somatostatin receptor (SSTR) analog that is widely used in the imaging of neuroendocrine tumors (NET). Benign and malignant prostate tumors have been observed to express SSTR. Diffuse symmetric DOTATOC uptake in the prostate is a normal positron emission tomography (PET) finding. The aim of this study was to evaluate the frequency and clinical significance of incidental atypical prostatic uptake in men undergoing 68 Ga-DOTATOC PET/computed tomography(CT)., Subjects and Methods: A retrospective review of consecutive male patients who underwent 68 Ga-DOTATOC PET/CT studies at Aalborg University Hospital, Denmark, from November 2010 to April 2020 was performed. Positron emission tomography/CT reports were searched for text words or phrases indicating incidental atypical prostatic uptake. In the resulting cohort, PET/CT were re-evaluated, and DOTATOC uptake in the prostate gland was categorized as focal, diffuse or mixed. The intensity of the uptake was visually graded using the Krenning visual score. Follow-up was based on all available clinical, biochemical, imaging, and pathology follow-up., Results: A total of 178 male patients underwent 193 68 Ga-DOTATOC PET/CT scans. Incidental atypical uptake of 68 Ga-DOTATOC on PET/CT in the prostatic bed was observed in eight patients (4.5%) (mean age 67 years, range 58-85 years). Six patients (75%) had diffuse uptake; two (25%) patients had focal uptake. Four patients out of eight with incidental findings (50%) had uptake less than or equal to that of the liver (Krenning score 2); four patients (50%) had uptake greater than that of the liver (score 3). All patients had measurements of serum prostate-specific antigen and were referred for urological evaluation. Five patients (62%) underwent a transrectal ultrasound, and three required a biopsy of the prostate. No cases of prostate malignancy (including prostatic cancer) were diagnosed., Conclusion: During a 10-year period, we found that 4.5% of men exhibited prostate incidentalomas on 68 Ga-DOTATOC PET/CT. No malignancy was found in the prostate in this population. Our data indicate absent malignancy among incidental 68 Ga-DOTATOC findings in the prostate.

Aim: We aimed to evaluate the prevalence of incidental 68  Ga-DOTA-conjugated somatostatin receptor-targeting peptide PET/CT (SSTR PET/CT) findings, their clinical significance in the need for follow-up, and their risk of malignancy., Materials and Methods: Studies reporting incidental SSTR PET/CT findings were systematically searched in PubMed, Cochrane, Embase and Web of Science literature published prior to 1 st of May 2020. Studies were filtered by two independent readers for eligibility based on title and abstract, and subsequently on full text. The main exclusion criteria were: 1) pathological findings that matched scan indication, 2) known organ specific disease and/or incidental findings confirmed on other scan modality prior to SSTR PET/CT, 3) lack of diagnosis and/or follow up, and 4) results published in proceedings or conference abstracts., Results: Twenty-one studies, comprising a total of 2906 subjects, were eligible for the analysis. Studies included were retrospective cohort studies on incidental SSTR PET/CT findings in a specific organ (n = 2888, 7/21) or case reports (n = 18, 14/21). A total of 133 subjects had incidental SSTR PET/CT findings. Incidental findings were predominantly seen in the thyroid gland (n = 65), spine (n = 30), brain (n = 26) and breast (n = 6). Seventeen of 133 (13%) incidental findings were malignant on final diagnosis. Incidental breast findings were associated with the highest risk of malignancy (67%). In the thyroid, incidental SSTR uptake was caused by malignancy in 8%, all presenting as focal uptake. The lowest risk was seen in the spine with a malignancy rate of 3% in patients with incidental SSTR uptake and benign cases were interpreted as vertebral hemangiomas on CT. Incidental SSTR PET/CT findings in other locations were of malignant etiology in two out of six cases (33%) and should be evaluated individually., Conclusion: The most incidental SSTR PET/CT findings were found in the thyroid gland, spine, and brain. The risk of malignancy was greatest in incidental SSTR PET/CT findings in the breast, cranially, and thyroid gland. The results of the present study can prove useful in the interpretation of atypical findings on SSTR PET/CT and in the counseling of clinicians., (© 2022. The Author(s).)

Objective: Gallium-68-prostate-specific membrane antigen positron emission tomography/computed tomography ( 68 Ga-PSMA PET/CT) has become a well-established imaging method for the evaluation of patients with prostate cancer. However, several cases have revealed PSMA uptake in a large variety of conditions other than prostate cancer. Prostate-specific membrane antigen uptake in thyroid cancer has also been reported. The aim of the present study was to systematically investigate the prevalence and clinical significance of thyroid incidental findings in patients undergoing 68 Ga-PSMA PET/CT., Materials and Methods: We retrospectively identified all patients referred for 68 Ga-PSMA PET/CT at the Department of Nuclear Medicine, Aalborg University Hospital, Denmark between May 2015 and May 2019. Patients with increased PSMA uptake in the thyroid gland were included in the analysis. Follow-up included imaging, biochemical, and/or histopathological collected over six months., Results: A total of 341 patients were included. Increased 68 Ga-PSMA uptake in the thyroid gland was observed in 13 patients (4%). Focal uptake was observed in seven patients, diffuse uptake in five patients and mixed focal and diffuse uptake in one patient. Malignancy was verified in two patients (2/13 patients, 15%), both patients with focal PSMA uptake., Conclusion: Gallium-68-PSMA thyroid incidental findings are rare in prostate cancer patients. However, cases of focal PSMA uptake in the thyroid gland should be further investigated, as these findings may represent metastatic or primary malignancy of the thyroid gland.