Diagnostic Performance of [18F]Fluorocholine and [68Ga]Ga-PSMA PET/CT in Prostate Cancer: A Comparative Study

Zeinab Paymani,Mohsen Beheshti,Nafiseh Alemohammad,Reza Vali,Hans Geinitz,Taryn Rohringer,Wolfgang Loidl,Werner Langsteger

doi:10.3390/jcm9072308

Abstract

The current study endeavored to closely compare the detection rate of 68-Gallium labelled prostate-specific membrane antigen ([68Ga]Ga-PSMA) versus [18F]Fluorocholine in men with prostate cancer (PC), to investigate the benefits and pitfalls of each modality in the setting of various patient characteristics. We retrospectively analyzed 29 biopsy-proven PC patients in two categories, staging and restaging, who underwent both scans within a maximum of 30 days of each other. Variables including patient demographics, prostate specific antigen (PSA) level, Gleason score, clinical course, and following treatments were recorded. The number and location of suspicious lesions as well as uptake values were noted. A total of 148 suspicious lesions were detected, of which 70.9% (105/148) were concordantly visualized in both imaging modalities. [68Ga]Ga-PSMA positron emission tomography/computed tomography (PET/CT) revealed a higher number of metastatic lesions per patients (91% vs 78%). The mean of maximum standardized uptake value (SUV max) in concordant lesions was significantly higher in [68Ga]Ga-PSMA compared to [18F]Fluorocholine PET/CT (14.6 ± 8.44 vs. 6.9 ± 3.4, p = 0.001). Discordant lesions were detected by both modalities, but more frequently by [68Ga]Ga-PSMA PET/CT (20.3% in [68Ga]Ga-PSMA versus 8.8% by [18F]Fluorocholine PET/CT). In patients with PSA levels below 1.0 ng/mL and <2.0 ng/mL, [18F]Fluorocholine PET/CT detection rate was half (57% and 55%, respectively) that of [68Ga]Ga-PSMA PET/CT. Tumor, nodes and metastases (TNM) staging, and subsequently patient management, was only influenced in 4/29 patients (14%), particularly by [68Ga]Ga-PSMA PET/CT with PSA values under 0.5 ng/mL. [68Ga]Ga-PSMA PET/CT revealed superior diagnostic performance to [18F]Fluorocholine PET/CT in staging and restaging of PC patients, especially in cases with low PSA levels. However, in a few hormone resistant high-risk PC patients, [18F]Fluorocholine PET/CT may improve overall diagnostic accuracy.

Highlights

Prostate cancer (PC) is the second most common malignancy and the fifth leading cause of cancer death in men, with more than 350,000 deaths estimated globally in 2018 [1] Regarding the heterogeneous nature of the disease, accurate staging and precise localization of the lesions by proper imaging modalities significantly affects treatment selection and improves outcomes for each patient [2,3]
Discordant lesions were detected by both modalities, but more frequently by [68Ga]Ga-Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/computed tomography (CT)), in association with lower prostate-specific antigen (PSA) values and hepatic metastases. [18F]Fluorocholine PET/CT exclusively detected 13.3% of skeletal and 7.3% of distant nodal involvements
We found no correlation between Gleason Scores or ongoing Androgen-deprivation therapy (ADT) with morphological findings and Hounsfield units on CT

Summary

Introduction

Prostate cancer (PC) is the second most common malignancy and the fifth leading cause of cancer death in men, with more than 350,000 deaths estimated globally in 2018 [1] Regarding the heterogeneous nature of the disease, accurate staging and precise localization of the lesions by proper imaging modalities significantly affects treatment selection and improves outcomes for each patient [2,3]. For staging disease in patients diagnosed with intermediate- to high-risk prostate cancer, as well as those with biochemical recurrence (BCR), current guidelines recommend computed tomography (CT) of the abdomen and pelvis, abdominopelvic magnetic resonance imaging (MRI), and/or whole-body bone scintigraphy [6,7,8]. Though detection and accurate localization of recurrence is necessary for further effective management, conventional imaging modalities lack sufficient sensitivity, especially in cases with low prostate-specific antigen (PSA) values [7,9,10,11]. They have been demonstrated to frequently under-stage metastases [6]. CT and MRI may misinterpret small lesions under 8–10 mm in diameter, and bone scintigraphy suffers from inadequate sensitivity for the detection of osteolytic lesions and may misdiagnose benign degeneration as osteoblastic malignant lesions [6,10,11]

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Discussion

Conclusion