Near-infrared fluorescence lymph node template region dissection plus backup lymphadenectomy in open radical cystectomy for bladder cancer using an innovative handheld device: A single center experience.

BACKGROUND: The extent of pelvic lymphadenectomy (PLND) as part of radical cystectomy (RC) for bladder cancer (BC) remains unclear. Sentinel-based and lymphangiographic approaches could lead to reduced morbidity without sacrificing oncologic safety. OBJECTIVE: To evaluate the feasibility and diagnostic value of fluorescence-guided template sentinel region dissection (FTD) using a handheld near-infrared fluorescence (NIRF) camera in open radical cystectomy. DESIGN, SETTING, AND PARTICIPANTS: After peritumoral cystoscopic injection of indocyanine green (ICG) 21 patients underwent open RC with FTD due to BC between June 2019 and June 2021. Intraoperatively, the FIS-00 Hamamatsu Photonics® NIRF camera was used to identify and resect fluorescent template sentinel regions (FTRs) followed by extended pelvic lymphadenectomy (ePLND) as oncological back-up. OUTCOME MEASUREMENT AND STATISTICAL ANALYSIS: Descriptive analysis of positive and negative results per template region. RESULTS AND LIMITATIONS: FTRs were identified in all 21 cases. Median time (range) from ICG injection to fluorescence detection was 75 (55-125) minutes. On average (SD), 33.4 (9.6) lymph nodes were dissected per patient. Considering template regions as the basis of analysis, 67 (38.3%) of 175 resected regions were NIRF-positive, with 13 (7.4%) regions harboring lymph node metastases. We found no metastatic lymph nodes in NIRF-negative template regions. Outside the standard template, two NIRF-positive benign nodes were identified. CONCLUSION: The concept of NIRF-guided FTD proved for this group all lymph node metastases to be found in NIRF-positive template regions. Pending validation in a larger collective, resection of approximately 40% of standard regions may be sufficient and may result in less morbidity.

High fibroblast-activation-protein expression in castration-resistant prostate cancer supports the use of FAPI-molecular theranostics.

PURPOSE: To evaluate fibroblast-activation-protein (FAP) expression in different clinical stages of prostate cancer (PC) with regards to utility of [68 Ga]Ga-FAPI-04 PET/CT imaging in patients with castration-resistant PC (CRPC). METHODS: Tissue microarrays (TMAs) were constructed from prostatic tissue from 94 patients at different stages of PC (primary PC, patients undergoing neoadjuvant androgen deprivation therapy, CRPC, and neuroendocrine PC (NEPC)) and were stained with anti-FAP monoclonal antibody. A positive pixel count algorithm (H-Index) was used to compare FAP expression between the groups. Additionally, three men with advanced CRPC or NEPC underwent [68 Ga]Ga-FAPI-04 PET/CT, and PET positivity was analyzed. RESULTS: The mean H-index for benign tissue, primary PC, neoadjuvant androgen deprivation therapy before radical prostatectomy, CRPC, and NEPC was 0.018, 0.031, 0.042, 0.076, and 0.051, respectively, indicating a significant rise in FAP expression with advancement of disease. Corroborating these findings [68 Ga]Ga-FAPI-04 PET/CT was highly positive in men with advanced CRPC. CONCLUSION: Increased FAP tissue expression supports the use of FAP inhibitor (FAPI)-molecular theranostics in CRPC.

Intraoperative 68Ga-PSMA Cerenkov Luminescence Imaging for Surgical Margins in Radical Prostatectomy: A Feasibility Study.

Our objective was to assess the feasibility and accuracy of Cerenkov luminescence imaging (CLI) for assessment of surgical margins intraoperatively during radical prostatectomy. Methods: A single-center feasibility study included 10 patients with high-risk primary prostate cancer (PC). 68Ga-prostate-specific membrane antigen (PSMA) PET/CT scans were performed followed by radical prostatectomy and intraoperative CLI of the excised prostate. In addition to imaging the intact prostate, in the first 2 patients the prostate gland was incised and imaged with CLI to visualize the primary tumor. We compared the tumor margin status on CLI to postoperative histopathology. Measured CLI intensities were determined as tumor-to-background ratio. Results: Tumor cells were successfully detected on the incised prostate CLI images as confirmed by histopathology. Three of 10 men had histopathologically positive surgical margins (PSMs), and 2 of 3 PSMs were accurately detected on CLI. Overall, 25 (72%) of 35 regions of interest proved to visualize a tumor signal according to standard histopathology. The median tumor radiance in these areas was 11,301 photons/s/cm2/sr (range, 3,328-25,428 photons/s/cm2/sr), and median tumor-to-background ratio was 4.2 (range, 2.1-11.6). False-positive signals were seen mainly at the prostate base, with PC cells overlaid by benign tissue. PSMA immunohistochemistry revealed strong PSMA staining of benign gland tissue, which impacts measured activities. Conclusion: This feasibility showed that 68Ga-PSMA CLI is a new intraoperative imaging technique capable of imaging the entire specimen's surface to detect PC tissue at the resection margin. Further optimization of the CLI protocol, or the use of lower-energy imaging tracers such as 18F-PSMA, is required to reduce false-positives. A larger study will be performed to assess diagnostic performance.