Intraoperative Molecular Fluorescence Imaging of Pancreatic Cancer by Targeting Vascular Endothelial Growth Factor: A Multicenter Feasibility Dose-Escalation Study.

Tumor visualization with near-infrared fluorescence (NIRF) imaging might aid exploration and resection of pancreatic cancer by visualizing the tumor in real time. Conjugation of the near-infrared fluorophore IRDye800CW to the monoclonal antibody bevacizumab enables targeting of vascular endothelial growth factor A. The aim of this study was to determine whether intraoperative tumor-specific imaging of pancreatic cancer with the fluorescent tracer bevacizumab-800CW is feasible and safe. Methods: In this multicenter dose-escalation phase I trial, patients in whom pancreatic ductal adenocarcinoma (PDAC) was suspected were administered bevacizumab-800CW (4.5, 10, or 25 mg) 3 d before surgery. Safety monitoring encompassed allergic or anaphylactic reactions and serious adverse events attributed to bevacizumab-800CW. Intraoperative NIRF imaging was performed immediately after laparotomy, just before and after resection of the specimen. Postoperatively, fluorescence signals on the axial slices and formalin-fixed paraffin-embedded tissue blocks from the resected specimens were correlated with histology. Subsequently, tumor-to-background ratios (TBR) were calculated. Results: Ten patients with clinically suspected PDAC were enrolled in the study. Four of the resected specimens were confirmed PDACs; other malignancies were distal cholangiocarcinoma, ampullary carcinoma, and neuroendocrine tumors. No serious adverse events were related to bevacizumab-800CW. In vivo tumor visualization with NIRF imaging differed per tumor type and was nonconclusive. Ex vivo TBRs were 1.3, 1.5, and 2.5 for the 4.5-, 10-, and 25-mg groups, respectively. Conclusion: NIRF-guided surgery in patients with suspected PDAC using bevacizumab-IRDye800CW is feasible and safe. However, suboptimal TBRs were obtained because no clear distinction between pancreatic cancer from normal or inflamed pancreatic tissue was achieved. Therefore, a more tumor-specific tracer than bevacizumab-IRDye800CW for PDAC is preferred.

Validation of Novel Molecular Imaging Targets Identified by Functional Genomic mRNA Profiling to Detect Dysplasia in Barrett's Esophagus.

Barrett's esophagus (BE) is the precursor of esophageal adenocarcinoma (EAC). Dysplastic BE (DBE) has a higher progression risk to EAC compared to non-dysplastic BE (NDBE). However, the miss rates for the endoscopic detection of DBE remain high. Fluorescence molecular endoscopy (FME) can detect DBE and mucosal EAC by highlighting the tumor-specific expression of proteins. This study aimed to identify target proteins suitable for FME. Publicly available RNA expression profiles of EAC and NDBE were corrected by functional genomic mRNA (FGmRNA) profiling. Following a class comparison between FGmRNA profiles of EAC and NDBE, predicted, significantly upregulated genes in EAC were prioritized by a literature search. Protein expression of prioritized genes was validated by immunohistochemistry (IHC) on DBE and NDBE tissues. Near-infrared fluorescent tracers targeting the proteins were developed and evaluated ex vivo on fresh human specimens. In total, 1976 overexpressed genes were identified in EAC (n = 64) compared to NDBE (n = 66) at RNA level. Prioritization and IHC validation revealed SPARC, SULF1, PKCι, and DDR1 (all p < 0.0001) as the most attractive imaging protein targets for DBE detection. Newly developed tracers SULF1-800CW and SPARC-800CW both showed higher fluorescence intensity in DBE tissue compared to paired non-dysplastic tissue. This study identified SPARC, SULF1, PKCι, and DDR1 as promising targets for FME to differentiate DBE from NDBE tissue, for which SULF1-800CW and SPARC-800CW were successfully ex vivo evaluated. Clinical studies should further validate these findings.

Identification and Validation of Esophageal Squamous Cell Carcinoma Targets for Fluorescence Molecular Endoscopy.

Dysplasia and intramucosal esophageal squamous cell carcinoma (ESCC) frequently go unnoticed with white-light endoscopy and, therefore, progress to invasive tumors. If suitable targets are available, fluorescence molecular endoscopy might be promising to improve early detection. Microarray expression data of patient-derived normal esophagus (n = 120) and ESCC samples (n = 118) were analyzed by functional genomic mRNA (FGmRNA) profiling to predict target upregulation on protein levels. The predicted top 60 upregulated genes were prioritized based on literature and immunohistochemistry (IHC) validation to select the most promising targets for fluorescent imaging. By IHC, GLUT1 showed significantly higher expression in ESCC tissue (30 patients) compared to the normal esophagus adjacent to the tumor (27 patients) (p < 0.001). Ex vivo imaging of GLUT1 with the 2-DG 800CW tracer showed that the mean fluorescence intensity in ESCC (n = 17) and high-grade dysplasia (HGD, n = 13) is higher (p < 0.05) compared to that in low-grade dysplasia (LGD) (n = 7) and to the normal esophagus adjacent to the tumor (n = 5). The sensitivity and specificity of 2-DG 800CW to detect HGD and ESCC is 80% and 83%, respectively (ROC = 0.85). We identified and validated GLUT1 as a promising molecular imaging target and demonstrated that fluorescent imaging after topical application of 2-DG 800CW can differentiate HGD and ESCC from LGD and normal esophagus.

Back-Table Fluorescence-Guided Imaging for Circumferential Resection Margin Evaluation Using Bevacizumab-800CW in Patients with Locally Advanced Rectal Cancer.

Negative circumferential resection margins (CRM) are the cornerstone for the curative treatment of locally advanced rectal cancer (LARC). However, in up to 18.6% of patients, tumor-positive resection margins are detected on histopathology. In this proof-of-concept study, we investigated the feasibility of optical molecular imaging as a tool for evaluating the CRM directly after surgical resection to improve tumor-negative CRM rates. Methods: LARC patients treated with neoadjuvant chemoradiotherapy received an intravenous bolus injection of 4.5 mg of bevacizumab-800CW, a fluorescent tracer targeting vascular endothelial growth factor A, 2-3 d before surgery (ClinicalTrials.gov identifier: NCT01972373). First, for evaluation of the CRM status, back-table fluorescence-guided imaging (FGI) of the fresh surgical resection specimens (n = 8) was performed. These results were correlated with histopathology results. Second, for determination of the sensitivity and specificity of bevacizumab-800CW for tumor detection, a mean fluorescence intensity cutoff value was determined from the formalin-fixed tissue slices (n = 42; 17 patients). Local bevacizumab-800CW accumulation was evaluated by fluorescence microscopy. Results: Back-table FGI correctly identified a tumor-positive CRM by high fluorescence intensities in 1 of 2 patients (50%) with a tumor-positive CRM. For the other patient, low fluorescence intensities were shown, although (sub)millimeter tumor deposits were present less than 1 mm from the CRM. FGI correctly identified 5 of 6 tumor-negative CRM (83%). The 1 patient with false-positive findings had a marginal negative CRM of only 1.4 mm. Receiver operating characteristic curve analysis of the fluorescence intensities of formalin-fixed tissue slices yielded an optimal mean fluorescence intensity cutoff value for tumor detection of 5,775 (sensitivity of 96.19% and specificity of 80.39%). Bevacizumab-800CW enabled a clear differentiation between tumor and normal tissue up to a microscopic level, with a tumor-to-background ratio of 4.7 ± 2.5 (mean ± SD). Conclusion: In this proof-of-concept study, we showed the potential of back-table FGI for evaluating the CRM status in LARC patients. Optimization of this technique with adaptation of standard operating procedures could change perioperative decision making with regard to extending resections or applying intraoperative radiation therapy in the case of positive CRM.

Setting Standards for Reporting and Quantification in Fluorescence-Guided Surgery.

PURPOSE: Intraoperative fluorescence imaging (FI) is a promising technique that could potentially guide oncologic surgeons toward more radical resections and thus improve clinical outcome. Despite the increase in the number of clinical trials, fluorescent agents and imaging systems for intraoperative FI, a standardized approach for imaging system performance assessment and post-acquisition image analysis is currently unavailable. PROCEDURES: We conducted a systematic, controlled comparison between two commercially available imaging systems using a novel calibration device for FI systems and various fluorescent agents. In addition, we analyzed fluorescence images from previous studies to evaluate signal-to-background ratio (SBR) and determinants of SBR. RESULTS: Using the calibration device, imaging system performance could be quantified and compared, exposing relevant differences in sensitivity. Image analysis demonstrated a profound influence of background noise and the selection of the background on SBR. CONCLUSIONS: In this article, we suggest clear approaches for the quantification of imaging system performance assessment and post-acquisition image analysis, attempting to set new standards in the field of FI.

Implementation and benchmarking of a novel analytical framework to clinically evaluate tumor-specific fluorescent tracers.

During the last decade, the emerging field of molecular fluorescence imaging has led to the development of tumor-specific fluorescent tracers and an increase in early-phase clinical trials without having consensus on a standard methodology for evaluating an optical tracer. By combining multiple complementary state-of-the-art clinical optical imaging techniques, we propose a novel analytical framework for the clinical translation and evaluation of tumor-targeted fluorescent tracers for molecular fluorescence imaging which can be used for a range of tumor types and with different optical tracers. Here we report the implementation of this analytical framework and demonstrate the tumor-specific targeting of escalating doses of the near-infrared fluorescent tracer bevacizumab-800CW on a macroscopic and microscopic level. We subsequently demonstrate an 88% increase in the intraoperative detection rate of tumor-involved margins in primary breast cancer patients, indicating the clinical feasibility and support of future studies to evaluate the definitive clinical impact of fluorescence-guided surgery.

Potential Red-Flag Identification of Colorectal Adenomas with Wide-Field Fluorescence Molecular Endoscopy.

Adenoma miss rates in colonoscopy are unacceptably high, especially for sessile serrated adenomas / polyps (SSA/Ps) and in high-risk populations, such as patients with Lynch syndrome. Detection rates may be improved by fluorescence molecular endoscopy (FME), which allows morphological visualization of lesions with high-definition white-light imaging as well as fluorescence-guided identification of lesions with a specific molecular marker. In a clinical proof-of-principal study, we investigated FME for colorectal adenoma detection, using a fluorescently labelled antibody (bevacizumab-800CW) against vascular endothelial growth factor A (VEGFA), which is highly upregulated in colorectal adenomas. Methods: Patients with familial adenomatous polyposis (n = 17), received an intravenous injection with 4.5, 10 or 25 mg of bevacizumab-800CW. Three days later, they received NIR-FME. Results: VEGFA-targeted NIR-FME detected colorectal adenomas at all doses. Best results were achieved in the highest (25 mg) cohort, which even detected small adenomas (<3 mm). Spectroscopy analyses of freshly excised specimen demonstrated the highest adenoma-to-normal ratio of 1.84 for the 25 mg cohort, with a calculated median tracer concentration in adenomas of 6.43 nmol/mL. Ex vivo signal analyses demonstrated NIR fluorescence within the dysplastic areas of the adenomas. Conclusion: These results suggest that NIR-FME is clinically feasible as a real-time, red-flag technique for detection of colorectal adenomas.

Data-Driven Prioritization and Review of Targets for Molecular-Based Theranostic Approaches in Pancreatic Cancer.

Molecularly targeted therapeutic and imaging strategies directed at aberrant signaling pathways in pancreatic tumor cells may improve the poor outcome of pancreatic ductal adenocarcinoma (PDA). Therefore, relevant molecular targets need to be identified. Methods: We collected publicly available expression profiles of patient-derived normal pancreatic tissue (n = 77) and PDA samples (n = 103). Functional genomic messenger RNA profiling was applied to predict target upregulation on the protein level. We prioritized these targets based on current status of preclinical therapeutic and imaging evaluation in PDA. Results: We identified 213 significantly upregulated proteins in PDA compared with normal pancreatic tissue. We prioritized mucin-1, mesothelin, γ-glutamyltransferase 5, and cathepsin-E as the most interesting targets, because studies already demonstrated their potential for both therapeutic and imaging strategies in literature. Conclusion: This study can assist clinicians and drug developers in deciding which theranostic targets should be taken for further clinical evaluation in PDA.

Molecular fluorescence-guided surgery of peritoneal carcinomatosis of colorectal origin: a single-centre feasibility study.

BACKGROUND: Optimum cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is essential for the curative treatment of peritoneal carcinomatosis of colorectal origin. At present, surgeons depend on visual inspection and palpation for tumour detection. Improved detection of tumour tissue using molecular fluorescence-guided surgery could not only help attain a complete cytoreduction of metastatic lesions, but might also prevent overtreatment by avoiding resection of benign lesions. METHODS: For this non-randomised, single-centre feasibility study, we enrolled patients with colorectal peritoneal metastases scheduled for cytoreductive surgery and HIPEC. 2 days before surgery, 4·5 mg of the near-infrared fluorescent tracer bevacizumab-IRDye800CW was administered intravenously. The primary objectives were to determine the safety and feasibility of molecular fluorescence-guided surgery using bevacizumab-IRDye800CW. Molecular fluorescence-guided surgery was deemed safe if no allergic or anaphylactic reactions were recorded and no serious adverse events were attributed to bevacizumab-IRDye800CW. The technique was deemed feasible if bevacizumab-IRDye800CW enabled detection of fluorescence signals intraoperatively. Secondary objectives were correlation of fluorescence with histopathology by back-table imaging of the fresh surgical specimen and semi-quantitative ex-vivo analyses of formalin-fixed paraffin embedded (FFPE) tissue on all peritoneal lesions. Additionally, VEGF-α staining and fluorescence microscopy was done. This study is registered with the Netherlands Trial Registry, number NTR4632. FINDINGS: Between July 3, 2014, and March 2, 2015, seven patients were enrolled in the study. One patient developed an abdominal sepsis 5 days postoperatively and another died from an asystole 4 days postoperatively, most probably due to a cardiovascular thromboembolic event. However, both serious adverse events were attributed to the surgical cytoreductive surgery and HIPEC procedure. No serious adverse events related to bevacizumab-IRDye800CW occurred in any of the patients. Intraoperatively, fluorescence was seen in all patients. In two patients, additional tumour tissue was detected by molecular fluorescence-guided surgery that was initially missed by the surgeons. During back-table imaging of fresh surgical specimens, a total of 80 areas were imaged, marked, and analysed. All of the 29 non-fluorescent areas were found to contain only benign tissue, whereas tumour tissue was detected in 27 of 51 fluorescent areas (53%). Ex-vivo semi-quantification of 79 FFPE peritoneal lesions showed a tumour-to-normal ratio of 6·92 (SD 2·47). INTERPRETATION: Molecular fluorescence-guided surgery using the near-infrared fluorescent tracer bevacizumab-IRDye800CW is safe and feasible. This technique might be of added value for the treatment of patients with colorectal peritoneal metastases through improved patient selection and optimisation of cytoreductive surgery. A subsequent multicentre phase 2 trial is needed to make a definitive assessment of the diagnostic accuracy and the effect on clinical decision making of molecular fluorescence-guided surgery. FUNDING: FP-7 Framework Programme BetaCure and SurgVision BV.

Television, sleep, outdoor play and BMI in young children: the GECKO Drenthe cohort.

UNLABELLED: In this study, we investigated the interplay between screen time, sleep duration, outdoor play, having a television in the bedroom and the number of televisions at home and their association with body mass index (BMI) in preschool children. All participants, 3-4 years of age (n = 759), were part of the Groningen expert center for kids with obesity (GECKO) Drenthe birth cohort. Weight and height were measured. Total screen time, number of televisions at home, a television in the bedroom, sleep duration and time of outdoor play were self-reported by parents in a questionnaire. Ordinary least square (OLS) regression-based path analysis was used to estimate direct and indirect effects on BMI in mediation models. A television in the bedroom or more televisions at home gave a higher screen time, which were associated with decreased sleep duration and resulted in higher BMI (indirect effect = 0.0115, 95% bootstrap interval = 0.0016; 0.0368 and indirect effect = 0.0026, 95% bootstrap interval = 0.0004; 0.0078, respectively). In contrast to the direct effect of screen time, sleep duration and a television in the bedroom on BMI, no direct effect was found for outdoor play and number or televisions at home on BMI. CONCLUSIONS: Short sleep duration, long screen time and a television in the bedroom were associated with the presence of overweight in preschool children.