Page 21 - ARNM-2-4

Advances in Radiotherapy
& Nuclear Medicine 68 Ga-PSMA PET CT/MRI in prostate cancer

1. Introduction its correlation with histopathology, and its performance
in TNM staging, as well as its correlation with targeted
Prostate cancer (PCa) is the second most commonly biopsies in conjunction with simultaneous computed
diagnosed cancer among men globally, necessitating tomography (CT) or magnetic resonance imaging (MRI).
1
effective early detection and accurate staging for optimal The search was performed in accordance with the Preferred
patient management. According to current guidelines, Reporting Items for Systematic Review and Meta-Analysis
conventional imaging remains the primary method for guidelines. The search terms included: (“Ga-68-PSMA-
imaging primary PCa. However, recent advancements PET” OR “Gallium-68 PSMA PET” OR “ Ga-PSMA-PET/
2
68
in imaging technology have introduced multiparametric CT” OR “prostate-specific membrane antigen PET”) AND
magnetic resonance imaging (mpMRI) and prostate- “systematic review.”
specific membrane antigen positron emission tomography
(PSMA-PET), have greatly improved the diagnosis of PCa. 2.2. Evidence synthesis
3,4
While mpMRI is valuable, it has drawbacks, including Using the systematic search strategy stated above, 110
moderate specificity, variable negative predictive values articles were identified. On initial screening, 21 were
coupled with interpretation variability, which highlights not relevant to the research question, and three were
the necessity for supplementary imaging modalities. 5-7
editorial comments or consensus documents that were
Gallium-68 ( Ga)-PSMA-PET has emerged as a excluded from the study. From the remaining 86 articles,
68
promising tool for the initial diagnosis of PCa, particularly 67 were excluded for one or more of the following reasons:
noted for its high sensitivity and specificity in detecting they lacked data relevant to the study outcomes, used
both primary and recurrent disease. Recent studies alternative imaging agents other than Ga-PSMA, or were
68
4
demonstrate that Ga-PSMA-PET surpasses conventional not available for thorough review. Articles that contained
68
imaging techniques in staging primary PCa and offers information about Ga-PSMA-PET were included in the
68
8,9
additional diagnostic benefits. This imaging modality study. Ultimately, 19 articles matched the inclusion criteria
is particularly effective in patients with intermediate-to (Figure 1).
high-risk PCa, offering improved accuracy in staging
and potentially guiding more precise biopsies. Unlike 2.3. Data extraction
4
traditional methods, Ga-PSMA-PET can identify PSMA- General details were retrieved for each study considered,
68
avid lesions, allowing for targeted biopsies that enhance such as generic data (authors and year of publication),
tissue sampling accuracy and improve risk stratification. 10 patients’ characteristics (number of patients), and diagnostic
Comparative studies between Ga-PSMA-PET and performance (type of imaging, sensitivity, and specificity).
68
mpMRI have highlighted the relative strengths of each 3. Results
modality. 68 Ga-PSMA-PET shows promise not only
in the initial diagnosis but also in correlating imaging 3.1. Initial diagnosis
findings with Gleason scores (GS) and providing detailed The literature review by Satapathy et al. noted that the
12
TNM staging. Its integration with mpMRI in PET/MRI 68 Ga-PSMA-PET has a high sensitivity (0.97) in the initial
studies leverages the anatomical features of MRI with detection of PCa, but highlighted its moderate specificity
the molecular imaging capabilities of Ga-PSMA-PET, (0.66) as a major drawback. Other studies in the literature
68
potentially offering a comprehensive approach to PCa review reported specificities ranging from 44.6% to
diagnosis and staging. 11 81.8%, with only one study reporting 100% specificity.

This review aims to investigate the role of Ga-PSMA- A possible explanation for this variability could be the use
68
PET in the initial diagnosis of PCa, its correlation with of normal metabolic activity found in the prostate gland
histopathology, and its performance in TNM staging. as the threshold for determining pet-positive lesions, as
Furthermore, it will evaluate how 68 Ga-PSMA-PET well as inter-observer variability in the way the imaging is
compares to mpMRI, particularly in combined PET/MRI performed and reported. 12,13
studies. A comprehensive review by Evangelista et al.
11
2. Materials and methods highlighted that integrated PET/MRI offers greater
diagnostic value in locating PCa than either mpMRI or
2.1. Search strategy PET imaging alone. This conclusion was supported by
A systematic review of the literature was conducted using several primary studies cited in the review.
PubMed to retrieve systematic reviews focusing on the The integration of Ga-PSMA-PET with MRI-targeted
68
role of Ga-PSMA imaging in the initial diagnosis of PCa, biopsy has demonstrated enhanced initial diagnosis of
68
Volume 2 Issue 4 (2024) 2 doi: 10.36922/arnm.4590