Marjory Koller

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.

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.

Setting Standards for Reporting and Quantification in Fluorescence-Guided Surgery

PurposeIntraoperative 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.ProceduresWe 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.ResultsUsing 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.ConclusionsIn 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.

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.

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.Fluorescent tracers are being tested in clinical trials to improve detection of tumor margins, but procedures are not standardised. Here, the authors develop an analytical framework that is compatible with the workflow in the operating theatre, and show that it leads to an 88% increase in intraoperative detection of tumor margins in patients with breast cancer.