Comparison of 68Ga-PSMA-11 PET/CT with 11C-acetate PET/CT in re-staging of prostate cancer relapse

Abstract

positron emission tomography (pet) imaging is used to localize recurrent disease in prostate cancer (pca). the tracer 68 Ga-PSMA-11 visualizes lesions overexpressing prostate-specific membrane antigen (pSMA), while 11 c-acetate visualizes lesions with increased anabolic metabolism. the aim of this study was to compare the performance of pSMA-pet and acetate-pet in re-staging patients with biochemical relapse. Thirty PCa patients with prostate-specific antigen (PSA) relapse after primary curative therapy were prospectively evaluated. PET/CT examinations using 11 c-acetate and 68 Ga-PSMA-11 were performed. Identified lesions were categorized according to anatomical location and pet measurements were correlated with pSA at time of scan. tumour lesions showed higher semiquantitative uptake values on PSMA-PET than acetate-PET. PSMA-PET identified more lesions in 11 patients, fewer lesions in eight patients, and identical number of lesions in 11 patients. This study indicates better diagnostic performance of PSMA-PET, particularly in detecting lymph node (81% vs 60%, p = 0.02) and bone metastasis (95% vs 61%, p = 0.0001) compared to acetate-PET. However, 38% of PSMA-expressing metastases appear to be metabolically inactive and 15% of metabolically active metastases lack PSMA expression. Addition of PET with a metabolic tracer, such as 11 c-acetate, might be beneficial before making treatment decisions.

More Than Meets the Eye: Scientific Rationale behind Molecular Imaging and Therapeutic Targeting of Prostate-Specific Membrane Antigen (PSMA) in Metastatic Prostate Cancer and Beyond

“…Lipid metabolism has also been suggested to play a crucial role in the metastasis process [ 142 ]. However, in prostate cancer patients the diagnostic performance was better for 68 Ga-PSMA-11 PET than 11 C-acetate PET in detecting metastatic lesions [ 143 ].…”

Application of Advanced Imaging to Prostate Cancer Diagnosis and Management: A Narrative Review of Current Practice and Unanswered Questions

“…Several radioligands are available for PET imaging of prostate cancer, leveraging differences in functional pathways and structural cellular components between prostate cancer cells and surrounding tissues. Commonly available radioligands that query metabolic activity include 11 C-acetate, 11 C-choline, 18 F-choline, 18 F-fluciclovine (Axumin TM ), and 18 F sodium fluoride (Na 18 F) [2,30]. Choline is a cell membrane component involved in cell membrane synthesis [31], while acetate is involved in the tricarboxylic acid cycle and lipid synthesis [32].…”

“…Prostate-specific membrane antigen (PSMA) radioligands target a transmembrane zinc metalloenzyme that is upregulated and overexpressed by prostate cancer cells compared with other tissues that contain the protein. These include salivary and lacrimal glands, spleen, liver, small intestine, kidney, pleura, and endometrium [30,31,35,36]. The degree of PSMA expression is reported in a standardized fashion with miPSMA scoring and has been associated with prostate cancer aggressiveness and prognosis [36,37].…”

“…For example, PSMA PET outperforms 11 C-acetate diagnostically; however, while most lesions are both PSMA and 11 C-acetate avid, 38% of PSMA avid metastases lack 11 C-acetate uptake and are metabolically inactive. It has also been observed that 15% of metabolically active 11 C-acetate positive metastasis do not express PSMA [30]. Thus, unexpected findings on molecular imaging should be considered in the context of the patient's cancer history as well as other co-morbid conditions, with consideration for biopsy, surveillance, and/or repeat imaging with alternative radiotracers.…”

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 ).…”