Large Paraesophageal Schwannoma With Intense Prostate-Specific Membrane Antigen Expression on 68Ga-PSMA-PET/CT Mimicking Lymph Node Metastasis in a Patient With Prostate Cancer

213 Background: Metastases-directed therapy by metastasectomy or radiotherapy (RT) might delay disease progression and postpone systemic treatment in patients with oligometastatic prostate cancer. Here, we evaluated retrospectively the efficacy and toxicity of 68Ga prostate-specific membrane antigen (PSMA) PET-CT guided radiotherapy (RT) in the treatment of oligometastatic prostate cancer. Methods: A total of 23 prostate cancer patients with biochemical relapse, of which 13 castration-sensitive and 10 castration-resistant, were treated with intensity-modulated and image-guided RT (IMRT-IGRT) on ≤ 3 metastases detected by 68Ga PSMA PET-CT. Androgen deprivation therapy was continued in castration-resistant patients. Local control (LC), progression-free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method. Results: A total of 38 metastases were treated. Involved sites were pelvic bone (n = 16), pelvic lymph nodes (n = 11), para-aortic lymph nodes (n = 6), ribs (n = 3) and vertebral body (n = 2). The median PSA prior to RT was 1.06 ng/ml (range 0.10 – 29.0 ng/ml). A median dose of 43.5 Gy (range, 30-64 Gy) was delivered by IMRT-IGRT in 12-27 fractions. At a median follow-up of 7 months (range, 2-17 months), 19 patients (83%) are in remission. Four patients (17%) developed distant recurrence. The actuarial 1-year LC, PFS and OS rates were 100%, 51% (95% CI 8-83%) and 100%. Castration-sensitive patients displayed a statistically significantly superior PFS on univariate analysis as compared to castration-resistant patients (1-year PFS 67% vs 0%, p < 0.01). One patient experienced grade 2 acute gastro-intestinal toxicity. No grade 3 or more toxic events were observed. Conclusions: By providing optimal LC, low toxicity and a promising PFS in castration-sensitive patients, the current retrospective study illustrated that 68Ga PSMA PET-CT guided RT may be an attractive treatment option in patients with oligometastatic prostate cancer. Validation by randomized trials is eagerly awaited.

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Prostate-specific membrane antigen and fibroblast activation protein distribution in prostate cancer: preliminary data on immunohistochemistry and PET imaging

Annals of Nuclear Medicine ◽

10.1007/s12149-021-01702-8 ◽

2021 ◽

Author(s):

Katharina Kessel ◽

Robert Seifert ◽

Matthias Weckesser ◽

Martin Boegemann ◽

Sebastian Huss ◽

...

Keyword(s):

Prostate Cancer ◽

Lymph Node ◽

Pet Imaging ◽

Fibroblast Activation Protein ◽

Prostate Specific Membrane Antigen ◽

Psma Pet ◽

Node Metastases ◽

Small Patient ◽

Specific Membrane ◽

Psma Expression

Abstract Introduction Fibroblast activation protein (FAP) has been recently presented as new imaging target for malignant diseases and offers high contrast to surrounding normal tissue. FAP tracer uptake has been reported in various tumor entities. The aim of this study was to compare FAP and Prostate-specific membrane antigen (PSMA) expression in primary prostate cancer employing histological analyses and PET imaging in two small patient collectives. Methods Two independent small patient collectives were included in this study. For cohort A, data of 5 prostate cancer patients and 3 patients with benign prostate hyperplasia were included. Patients with prostate cancer were initially referred for PSMA PET staging. Radical prostatectomy was performed in all patients and prostate specimen of patients and biopsies of healthy controls were available for further evaluation. Histological workup included HE and immunohistochemistry using PSMA Ab, FAP Ab. Cohort B consists of 6 Patients with diagnosed mCRPC and available PSMA as well as FAP PET. Results Patients with proven prostate cancer infiltration exhibited strong positivity for PSMA in both primary tumors and lymph node metastases while stainings for FAP were found positive in some cases, but not all (2/5). Controls with BPH presented moderate PSMA staining and in one case also with a positive FAP staining (1/3). PET imaging with FAP seemed to result in more precise results in case of low PSMA expression than PSMA-PET. Conclusions While PSMA staining intensity is a valid indicator of prostate cancer in both primary tumor and lymph node metastases, the expression of FAP seems to be heterogeneous but not necessarily linked to cancer-associated fibroblasts. It is also present in inflammation-associated myofibroblasts. Therefore, its ultimate role in prostate cancer diagnosis remains a subject of discussion.

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Head-to-head comparison of 68Ga-prostate-specific membrane antigen PET/CT and ferumoxtran-10 enhanced MRI for the diagnosis of lymph node metastases in prostate cancer patients

Journal of Nuclear Medicine ◽

10.2967/jnumed.120.258541 ◽

2021 ◽

pp. jnumed.120.258541

Author(s):

Melline GM Schilham ◽

Patrik Zamecnik ◽

Bastiaan M Privé ◽

Bas Israël ◽

Mark Rijpkema ◽

...

Keyword(s):

Prostate Cancer ◽

Lymph Node ◽

Cancer Patients ◽

Lymph Node Metastases ◽

Prostate Specific Membrane Antigen ◽

Enhanced Mri ◽

Pet Ct ◽

Node Metastases ◽

Specific Membrane

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Detection rates of recurrent prostate cancer: 68Gallium (Ga)-labelled prostate-specific membrane antigen versus choline PET/CT scans. A systematic review

Therapeutic Advances in Urology ◽

10.1177/1756287218815793 ◽

2019 ◽

Vol 11 ◽

pp. 175628721881579 ◽

Cited By ~ 6

Author(s):

Masood Moghul ◽

Bhaskar Somani ◽

Tim Lane ◽

Nikhil Vasdev ◽

Brian Chaplin ◽

...

Keyword(s):

Prostate Cancer ◽

Systematic Review ◽

Ct Scans ◽

Prostate Specific Membrane Antigen ◽

Recurrent Prostate Cancer ◽

Detection Rates ◽

Psma Pet ◽

Pet Ct ◽

Significant Difference ◽

Specific Membrane

Background: The aim of this work was to assess the use of prostate-specific membrane antigen (PSMA)-labelled radiotracers in detecting the recurrence of prostate cancer. PSMA is thought to have higher detection rates when utilized in positron emission tomography (PET)/computed tomography (CT) scans, particularly at lower prostate-specific antigen (PSA) levels, compared with choline-based scans. Methods: A systematic review was conducted comparing choline and PSMA PET/CT scans in patients with recurrent prostate cancer following an initial curative attempt. The primary outcomes were overall detection rates, detection rates at low PSA thresholds, difference in detection rates and exclusive detection rates on a per-person analysis. Secondary outcome measures were total number of lesions, exclusive detection by each scan on a per-lesion basis and adverse side effects. Results: Overall detection rates were 79.8% for PSMA and 66.7% for choline. There was a statistically significant difference in detection rates favouring PSMA [OR (M–H, random, 95% confidence interval (CI)) 2.27 (1.06, 4.85), p = 0.04]. Direct comparison was limited to PSA < 2 ng/ml in two studies, with no statistically significant difference in detection rates between the scans [OR (M–H, random, 95% CI) 2.37 (0.61, 9.17) p = 0.21]. The difference in detection on the per-patient analysis was significantly higher in the PSMA scans ( p < 0.00001). All three studies reported higher lymph node, bone metastasis and locoregional recurrence rates in PSMA. Conclusions: PSMA PET/CT has a better performance compared with choline PET/CT in detecting recurrent disease both on per-patient and per-lesion analysis and should be the imaging modality of choice while deciding on salvage and nonsystematic metastasis-directed therapy strategies.

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