EpCAM as multi-tumour target for near-infrared fluorescence guided surgery.

BACKGROUND: Evaluation of resection margins during cancer surgery can be challenging, often resulting in incomplete tumour removal. Fluorescence-guided surgery (FGS) aims to aid the surgeon to visualize tumours and resection margins during surgery. FGS relies on a clinically applicable imaging system in combination with a specific tumour-targeting contrast agent. In this study EpCAM (epithelial cell adhesion molecule) is evaluated as target for FGS in combination with the novel Artemis imaging system. METHODS: The NIR fluorophore IRDye800CW was conjugated to the well-established EpCAM specific monoclonal antibody 323/A3 and an isotype IgG1 as control. The anti-EpCAM/800CW conjugate was stable in serum and showed preserved binding capacity as evaluated on EpCAM positive and negative cell lines, using flow cytometry and cell-based plate assays. Four clinically relevant orthotopic tumour models, i.e. colorectal cancer, breast cancer, head and neck cancer, and peritonitis carcinomatosa, were used to evaluate the performance of the anti-EpCAM agent with the clinically validated Artemis imaging system. The Pearl Impulse small animal imaging system was used as reference. The specificity of the NIRF signal was confirmed using bioluminescence imaging and green-fluorescent protein. RESULTS: All tumour types could clearly be delineated and resected 72 h after injection of the imaging agent. Using NIRF imaging millimetre sized tumour nodules were detected that were invisible for the naked eye. Fluorescence microscopy demonstrated the distribution and tumour specificity of the anti-EpCAM agent. CONCLUSIONS: This study shows the potential of an EpCAM specific NIR-fluorescent agent in combination with a clinically validated intraoperative imaging system to visualize various tumours during surgery.

Optimization of sentinel lymph node mapping in bladder cancer using near-infrared fluorescence imaging.

BACKGROUND AND OBJECTIVES: Unlike other cancers, the Sentinel Lymph Node (SLN) procedure in bladder cancer requires special attention to the injection technique. The aim of this study was to assess feasibility and to optimize tracer injection technique for SLN mapping in bladder cancer patients using NIR fluorescence imaging. METHODS: Twenty patients with invasive bladder cancer scheduled for radical cystectomy were prospectively enrolled. Indocyanine green (ICG) bound to human serum albumin (complex ICG:HSA; 500 µM) was injected peritumourally to permit SLN mapping. ICG:HSA was first administrated serosally (n = 5), and subsequently mucosally by cystoscopic injection (n = 15). In the last cohort of 12 patients treated with cystoscopic injection, the bladder was kept filled with saline for at least 15 min. RESULTS: Fluorescent lymph nodes were observed only in the patient group with cystoscopic injection of ICG:HSA. Filling of the bladder post-injection was of added value to promote drainage of ICG:HSA to the lymph nodes, and in 11 of these 12 patients (92%) one or more NIR fluorescent lymph nodes were identified. CONCLUSIONS: The current study demonstrates proof-of-principle of using NIR fluorescence imaging for SLN identification in bladder cancer. Cystoscopic injection with distension of the bladder appears optimal for SLN mapping.

Near-infrared fluorescence-guided metastasectomy for hepatic gastrointestinal stromal tumor metastases using indocyanine green: A case report.

INTRODUCTION AND IMPORTANCE: Gastrointestinal stromal tumors are the most prevalent mesenchymal tumors of the gastrointestinal tract. Distant metastases are most often found in the liver or peritoneum with surgery being the preferred treatment option. In our center, fluorescence-guided surgery with indocyanine green is used as standard-of-care for hepatic metastases in colorectal cancer. This case report describes fluorescence-guided metastasectomy for a hepatic gastrointestinal stromal tumor in two patients undergoing open liver resection and radiofrequency ablation. CASE PRESENTATION: A 69-year old women was seen during follow-up after laparoscopic resection of a GIST in the lesser curvature of the stomach. Contrast-enhanced computed tomography imaging showed two suspicious lesions in liver segment VI and VIII. Intraoperative near-infrared fluorescence imaging of the liver clearly revealed the lesion in segment VIII, and an additional lesion in segment V - which was not seen on preoperative CT-imaging, neither on intraoperative ultrasonography. The lesion in segment VI was not seen with NIRF imaging due to its deeper location in the liver parenchyma. The second case is an 82-year old man who was also diagnosed with liver metastases from a GIST in the stomach and was scheduled for near-infrared fluorescence-guided liver resection and radio frequency ablation. CLINICAL DISCUSSION: In this case report we demonstrated the feasibility of fluorescence-guided surgery in detection of liver metastases and treatment planning of two patients with hepatic GIST metastases using indocyanine green. CONCLUSION: NIRF-imaging with ICG is useful for identification of preoperatively discovered lesions, surgical resection planning and margin evaluation, and for detection of additional hepatic GIST metastases.

Real-time intraoperative detection of breast cancer using near-infrared fluorescence imaging and Methylene Blue.

BACKGROUND: Despite recent developments in preoperative breast cancer imaging, intraoperative localization of tumor tissue can be challenging, resulting in tumor-positive resection margins during breast conserving surgery. Based on certain physicochemical similarities between Technetium((99m)Tc)-sestamibi (MIBI), an SPECT radiodiagnostic with a sensitivity of 83-90% to detect breast cancer preoperatively, and the near-infrared (NIR) fluorophore Methylene Blue (MB), we hypothesized that MB might detect breast cancer intraoperatively using NIR fluorescence imaging. METHODS: Twenty-four patients with breast cancer, planned for surgical resection, were included. Patients were divided in 2 administration groups, which differed with respect to the timing of MB administration. N = 12 patients per group were administered 1.0 mg/kg MB intravenously either immediately or 3 h before surgery. The mini-FLARE imaging system was used to identify the NIR fluorescent signal during surgery and on post-resected specimens transferred to the pathology department. Results were confirmed by NIR fluorescence microscopy. RESULTS: 20/24 (83%) of breast tumors (carcinoma in N = 21 and ductal carcinoma in situ in N = 3) were identified in the resected specimen using NIR fluorescence imaging. Patients with non-detectable tumors were significantly older. No significant relation to receptor status or tumor grade was seen. Overall tumor-to-background ratio (TBR) was 2.4 ± 0.8. There was no significant difference between TBR and background signal between administration groups. In 2/4 patients with positive resection margins, breast cancer tissue identified in the wound bed during surgery would have changed surgical management. Histology confirmed the concordance of fluorescence signal and tumor tissue. CONCLUSIONS: This feasibility study demonstrated an overall breast cancer identification rate using MB of 83%, with real-time intraoperative guidance having the potential to alter patient management.