Levent Kabasakal

For active surveillance assessment, ⁶⁸ Ga-PSMA PET/CT was performed in a 73-year-old man with Gleason 3+3 prostate adenocarcinoma. PET/CT showed a markedly enlarged prostate indenting the bladder base, with focal midline activity suggestive of prostatic urethral urinary retention. Intravenous furosemide was administered before 120-minute delayed imaging, which showed complete resolution of the activity and excluded pathologic uptake. After discharge, he developed urinary urgency and incomplete emptying, progressing to lower abdominal and pelvic pain with elevated creatinine. Postrenal acute kidney injury from acute urinary retention was diagnosed. Catheterization and inpatient monitoring normalized renal function, highlighting an underrecognized risk of forced diuresis.

Purpose To develop and validate the Istanbul [⁶⁸Ga]Ga-PSMA PET/CT Criteria (IPPC), a standardized imaging framework designed to identify clinically significant prostate cancer (csPCa) and improve selection of candidates for active surveillance (AS). Methods [⁶⁸Ga]Ga-PSMA PET/CT scans and histopathology from 163 men with biopsy-proven International Society of Urological Pathology (ISUP) Grade Group (GG) 1–2 prostate cancer who underwent radical prostatectomy were retrospectively reviewed by a multidisciplinary panel of nuclear medicine physicians, radiologists, and urologists. Imaging characteristics—including uptake pattern, morphology, localization, and SUVmax—were iteratively analyzed to define three categories: IPPC-1 (indolent), IPPC-2 (indeterminate), and IPPC-3 (csPCa-suspected). Delayed pelvic acquisitions were used as the primary dataset to enhance lesion definition and interpretability. Reproducibility was evaluated in 56 GG1 patients using Cohen’s and Fleiss’ κ statistics. Correlations between PSA, SUVmax, and IPPC categories were assessed, and ROC curve analysis was performed to determine the optimal SUVmax threshold for csPCa detection. Results Pathological upgrading occurred in 40% of all cases (74% GG1, 20% GG2). Among 56 GG1 patients, upgrading was 76%. SUVmax and PSA were significantly higher in IPPC-3 than in IPPC-2 (SUVmax 16.3 vs. 6.5, p < 0.001; PSA 7.8 vs. 5.3 ng/mL, p < 0.05). ROC analysis yielded an AUC = 0.76 with an optimal SUVmax cut-off of 8.21 (sensitivity 55%, specificity 90%). All lesions with SUVmax ≥ 12.0 corresponded to csPCa. Interobserver agreement was substantial (κ ≈ 0.70–0.74) and intraobserver concordance strong (κ ≈ 0.80–0.90), confirming high reproducibility. Conclusion IPPC provides a reproducible, biologically grounded method that integrates SUVmax, morphology, and anatomical localization to non-invasively refine AS eligibility. By identifying patients at genuine risk for csPCa while minimizing unnecessary biopsies, IPPC may improve confidence and adherence in AS management. Prospective multicentre validation within the ongoing I-SELECT trial (NCT07168616) will determine its broader clinical applicability.

This study aimed to investigate the potential efficacy of [⁶⁸Ga]Ga-FAP-2286 PET/CT in evaluating treatment response in patients with gastrointestinal system malignancies. Patients with histopathologically confirmed gastrointestinal malignancies who underwent [⁶⁸Ga]Ga-FAP-2286 PET/CT for treatment response assessment between November 2020 and January 2025 were included. All images were evaluated by three experienced nuclear medicine physicians. The maximum standardized uptake values (SUVmax), total tumor volumes, and total lesion FAP expression values of primary tumors and metastases were recorded. At the same time, serum tumor marker levels were analyzed. Imaging responses were assessed separately according to PERCIST criteria on [⁶⁸Ga]Ga-FAP-2286 PET/CT and RECIST criteria on CT. Survival outcomes were analyzed using the Kaplan-Meier method, and their association with treatment response on [⁶⁸Ga]Ga-FAP-2286 PET/CT was assessed using the Log-Rank (Mantel-Cox) test and Cox proportional hazards regression. A p-value < 0.05 was considered statistically significant in all analyses. A total of 100 [⁶⁸Ga]Ga-FAP-2286 PET/CT scans were performed in 50 patients (mean age: 61.62 ± 12.95), both before and after treatment. Among the included patients, 70% had gastric cancer, 14% had colon cancer, 8% had pancreatic cancer, 4% had appendiceal cancer, 2% had hepatocellular carcinoma (HCC), and 2% had cholangiocellular carcinoma. Primary/recurrent tumor lesions were observed in 62% of patients, lymph node metastases in 24%, visceral metastases in 10%, peritoneal metastases in 76%, and bone metastases in 14%. A strong correlation was found between tumor volumes and total lesion FAP expression measured by [⁶⁸Ga]Ga-FAP-2286 PET/CT and the corresponding serum tumor markers (Area Under the Curve [AUC] for delta tumor volume and total lesion FAP expression = 0.875). There was a statistically significant and near-perfect concordance between [⁶⁸Ga]Ga-FAP-2286 PET PERCIST and CT RECIST criteria (Kappa = 0.833, p < 0.05). Moderate agreement was found for primary tumors (Kappa = 0.526, p < 0.05) and bone metastases (Kappa = 0.657, p < 0.05), while excellent agreement was observed for lymph node (Kappa = 1.0, p < 0.05), peritoneal (Kappa = 0.815, p < 0.05), and visceral metastases (Kappa = 1.0, p < 0.05). According to the Kaplan-Meier analysis, treatment response assessed by [⁶⁸Ga]Ga-FAP-2286 PET/CT was predictive of overall survival (p = 0.02). Median overall survival was 7.6 months in patients with progressive disease and 19.8 months in those with stable disease, as defined by PERCIST criteria. Median survival was not reached in patients showing partial or complete response. In gastrointestinal system malignancies, a strong correlation was observed between serum tumor markers and both total tumor volumes and total lesion FAP expression values derived from [⁶⁸Ga]Ga-FAP-2286 PET imaging. Additionally, molecular response assessed by [⁶⁸Ga]Ga-FAP-2286 PET/CT was predictive of overall survival. [⁶⁸Ga]Ga-FAP-2286 PET/CT appears to be an effective tool for assessing treatment response and monitoring patients with gastrointestinal malignancies.

Cancer Integrin Imaging with [68Ga]Ga-Trivehexin PET/CT for a Patient with Breast Cancer and Neuroendocrine Neoplasm: A Case of Both (18F)FDG PET/CT and [68Ga]Ga-DOTATATE Positive but Integrin avβ6 Negative Lesion on [68Ga]Ga-Trivehexin PET - Molecular Imaging and Radionuclide Therapy

Impact of 68Ga-FAPi PET/CT on Staging or Restaging Digestive System Tumors in Patients with Negative or Equivocal 18F-FDG PET/CT Findings - Molecular Imaging and Radionuclide Therapy

Improved Accuracy and Reliability of PRIMARY Scoring Using Delayed [68Ga] Ga-PSMA PET/CT Imaging - Molecular Imaging and Radionuclide Therapy

Background: The combination of Lutetium-177 (Lu-177) PSMA-617 radioligand therapy (RLT) with androgen receptor pathway inhibitors (ARPIs) has shown promise in metastatic castration-resistant prostate cancer (mCRPC). However, real-world data on the efficacy and safety of this combination are limited. This study aimed to evaluate the impact of combination therapy with Lu-177 PSMA-617 RLT and ARPIs on progression-free survival (PFS) and overall survival (OS) in patients with mCRPC. Methods: In this retrospective study, 104 mCRPC patients receiving Lu-177 PSMA-617 RLT at our institution between December 2017 and January 2024 were divided into the following two groups those receiving Lu-177 PSMA-617 RLT plus ARPI (n = 34) and those receiving Lu-177 PSMA-617 RLT alone (n = 70). Patients received 150 to 200 millicuries Lu-177 PSMA-617 RLT in each cycle. PFS and zOS were assessed using Kaplan–Meier analysis and Cox proportional hazard models. Results: The combination therapy significantly prolonged median PFS compared to Lu-177 PSMA-617 RLT alone (11 vs. 5.6 months; HR, 0.47; 95% CI, 0.28–0.79; p < 0.01). A trend towards improved OS was also observed in the combination group (20.3 vs. 15.9 months; HR, 0.58; 95% CI, 0.33–1.02; p = 0.06). Age was a significant predictor of OS (21.2 vs. 12.4 months for younger vs. older patients; p < 0.01), while Gleason score and visceral involvement did not significantly impact PFS. The safety profile indicated that adverse effects were generally comparable between the two groups, with no statistically significant differences in the incidence of anemia, neutropenia, thrombocytopenia, nephrotoxicity, or hepatotoxicity. Conclusions: This study provides evidence that combining Lu-177 PSMA-617 RLT with ARPIs may significantly improve PFS in mCRPC patients. The potential OS benefit warrants further investigation in larger prospective trials. Age should be considered when making treatment decisions for mCRPC patients.