The Journal of Nuclear Medicine最新文献

Both [¹⁸F]PSMA-1007 PET/CT and [¹⁸F]fluciclovine PET/CT scans are commonly used for prostate cancer (PCa) staging. To the best of our knowledge, no head-to-head comparison of these 2 scans for detection of intraprostatic clinically significant PCa (csPCa) has been published. Methods: A multicenter prospective histopathologic validation study was conducted from October 2020 to February 2023. Patients with newly diagnosed biopsy-proven intermediate- or high-risk PCa scheduled for robot-assisted radical prostatectomy (RARP) were consecutively included. Before RARP, patients underwent both [¹⁸F]PSMA-1007 PET/CT as well as [¹⁸F]fluciclovine PET/CT. The diagnostic accuracy of [¹⁸F]PSMA-1007 PET/CT and [¹⁸F]fluciclovine PET/CT for intraprostatic PCa detection and localization was established by histopathologic examination of the prostate specimen as reference. Sensitivity, specificity, positive predictive value, and negative predictive value were compared. Results were based on per-lesion analysis and per-segment analysis. The focus was set on csPCa, defined as the International Society of Urological Pathology grade group 2 or higher. Results: In total, 77 patients were included of whom 57 underwent both PET/CT scans before RARP. Histopathology of the prostate specimen found a total of 88 lesions, of which 68 (77.3%) were qualified as csPCa. Using [¹⁸F]PSMA-1007 PET/CT, lesion-based sensitivity for csPCa was 86.8% (95% CI, 75.9%–93.4%), and with [¹⁸F]fluciclovine PET/CT, it was 73.5% (95% CI, 61.2%–83.2%). Sensitivity for segment-based csPCa localization was 46.6% (95% CI, 42.4%–50.8%) for [¹⁸F]PSMA-1007 PET/CT and 37.3% (95% CI, 33.3%–41.5%) for [¹⁸F]fluciclovine PET/CT. Whereas [¹⁸F]PSMA-1007 PET/CT has a significantly higher accuracy in the detection and localization of csPCa, [¹⁸F]fluciclovine PET/CT visualized all 5 non–[¹⁸F]PSMA-1007–avid index tumors. Conclusion: Compared with [¹⁸F]fluciclovine PET/CT, [¹⁸F]PSMA-1007 PET/CT demonstrated higher sensitivity for csPCa detection. However, in non–[¹⁸F]PSMA-1007–avid tumors, the [¹⁸F]fluciclovine PET/CT can visualize csPCa and has therefore a potential role in the diagnostic work-up and the clinical decision-making process.

The Pelvic Rosetta Classification (PRC) project aimed to develop an interdisciplinary, landmark-based pelvic lymph node map for patients with prostate cancer to improve communication between imaging specialists and urologists. Methods: After an intense development phase, we conducted 3 evaluation rounds including 19 clinical experts having consensus meetings after each evaluation round. Experts contoured lymph node areas (LNA) for 2 patients with prostate cancer. Contours were assessed qualitatively and quantitatively. The PRC was further validated by assignment of 30 prostate-specific membrane antigen PET/CT–positive lesions to LNAs. The interrater reliability was calculated using Fleiss κ. Based on the final PRC, a complete contour and a 3-dimensional model were created. Results: Eight pelvic (external iliac, cranial/caudal obturator fossa, dorsal internal iliac, vesico-prostatic pedicle, mesorectal/perirectal, presacral, preprostatic/retropubic) and 4 extrapelvic (common iliac, intercommon, sigmoid, inguinal) LNAs were defined using anatomic landmarks which are consistently recognizable on imaging and intraoperatively. Strong consensus between experts existed for smaller, well-defined LNAs (e.g., preprostatic/retropubic, mesorectal/perirectal LNAs) compared with regions with proportionally large borders (e.g., obturator fossa, vesico-prostatic pedicle LNAs). Overall, moderate agreement (κ = 0.53) was observed during validation. Discrepancies were mostly encountered for lesions adjacent to borders between LNAs. The final contour and 3-dimensional model were approved by all experts. Conclusion: The PRC project showed fair reproducibility and validity. Further external validation is needed to assess its influence on interdisciplinary communication and treatment outcomes.

High expression of prostate-specific membrane antigen (PSMA) is not limited to prostate cancer but can be found in other tumor entities, such as hepatocellular carcinoma (HCC), and could possibly be used for theranostic purposes. Our aim was to investigate the diagnostic potential of the hepatobiliary excreted radiotracer [¹⁸F]PSMA-1007 on initial staging of HCC. Methods: This prospective clinical study (NCT05547919) included 10 participants (9 men, 1 woman) with treatment-naïve, histopathologically proven PSMA-positive HCC. All participants underwent [¹⁸F]PSMA-1007 PET with unenhanced low-dose CT. All scans were analyzed visually and quantitatively. We assessed the SUV_max of the primary tumor and the SUV_mean of nonaffected liver parenchyma and calculated tumor-to-background ratios (i.e., SUV_max HCC/SUV_mean liver) for each patient. In addition, we assessed possible eligibility for PSMA-directed radiopharmaceutical therapy according to the PROMISE criteria. The presence of local lymph nodes and distant metastases was noted for [¹⁸F]PSMA-1007 PET/CT and compared with the results of contrast-enhanced CT of the trunk and MRI of the upper abdomen. Possible prognostic implications of PSMA expression on immunohistochemistry and on [¹⁸F]PSMA-1007 PET/CT were compared with progression-free survival (defined as clinical progression, radiographic progression, or death from any cause) using Cox regression. Results: [¹⁸F]PSMA-1007 PET showed high uptake in 7 of 10 patients (PROMISE score 2, n = 4; PROMISE score 3, n = 3); mediocre or missing uptake was found in 3 participants (PROMISE score 0, n = 1; PROMISE score 1, n = 2). The median tumor-to-background ratio was 2.7 (interquartile range, 2.65). [¹⁸F]PSMA-1007 PET did not reveal new distant metastatic lesions compared with contrast-enhanced CT. In 1 patient, local lymph node metastases were considered PSMA-negative despite high uptake in the primary tumor. Whether assessed ex vivo or in vivo, PSMA expression did not correlate with progression-free survival. Conclusion: [¹⁸F]PSMA-1007 can be used depict untreated HCC and shows high uptake relative to background, indicative of excellent image contrast. High tracer accumulation in 70% of the participants suggests a possible use for PSMA-directed radiopharmaceutical therapy in an end-stage setting. However, PSMA expression was not prognostic for outcome, possibly because of the small sample size.

⁶⁸Ga-PSMA-11 PET/CT (PSMA PET/CT) is used for staging advanced prostate cancer (PCa); however, its role in initial cancer detection and guiding localized treatment remains uncertain. The primary objective of this study was to assess the impact of upfront PSMA PET/CT on treatment decision-making based on imaging and biopsy-derived information. Methods: In this prospective, phase 2 interventional trial, 230 biopsy- and imaging-naïve men with suspected PCa underwent PSMA PET/CT and multiparametric MRI (mpMRI) before targeted ultrasound fusion and systematic biopsy. Randomized assessor teams independently reviewed histopathology and imaging data from either the mpMRI or the combined mpMRI plus PSMA PET/CT pathway and formulated treatment plans accordingly. Patient recruitment was conducted between 2021 and 2023. Results: Among 137 patients with PCa (9% low-, 35% intermediate-, and 15% high-risk disease), PSMA PET/CT altered management plans in 34% of patients, primarily modifying local treatment strategies, including lymph node dissection (16%), a nerve-sparing procedure (18%), and radiation field adjustments (28%). Systemic therapy escalation was rare (1%). In addition, 2% of patients initiated active treatment, 5% received adjunctive hormone therapy, and 7% underwent metastasis-directed therapy. Upfront PSMA PET/CT prompted treatment intensification at comparable rates in both intermediate-risk (31%) and high-risk (30%) PCa with high interrater agreement (Cohen κ, 0.71; 95% CI, 0.61–0.80). Prostate-specific antigen density of at least 0.15 ng/mL³ (odds ratio, 2.48; 95% CI, 1.22–5.06) and abnormal digital rectal examination (odds ratio, 2.12; 95% CI, 1.03–4.33) predicted PSMA PET/CT–driven changes. Conclusion: Early PSMA PET/CT staging altered treatment strategies for up to one third of patients with intermediate- and high-risk PCa by enhancing metastasis detection and local tumor characterization. Its effect on oncologic and functional outcomes warrants further investigation.