Multispectral optoacoustic tomography for in vivo detection of lymph node metastases in oral cancer patients using an EGFR-targeted contrast agent and intrinsic tissue contrast: A proof-of-concept study.

Oral cancer patients undergo diagnostic surgeries to detect occult lymph node metastases missed by preoperative structural imaging techniques. Reducing these invasive procedures that are associated with considerable morbidity, requires better preoperative detection. Multispectral optoacoustic tomography (MSOT) is a rapidly evolving imaging technique that may improve preoperative detection of (early-stage) lymph node metastases, enabling the identification of molecular changes that often precede structural changes in tumorigenesis. Here, we characterize the optoacoustic properties of cetuximab-800CW, a tumor-specific fluorescent tracer showing several photophysical properties that benefit optoacoustic signal generation. In this first clinical proof-of-concept study, we explore its use as optoacoustic to differentiate between malignant and benign lymph nodes. We characterize the appearance of malignant lymph nodes and show differences in the distribution of intrinsic chromophores compared to benign lymph nodes. In addition, we suggest several approaches to improve the efficiency of follow-up studies.

Fluorescence grid analysis for the evaluation of piecemeal surgery in sinonasal inverted papilloma: a proof-of-concept study.

PURPOSE: Local recurrence occurs in ~ 19% of sinonasal inverted papilloma (SNIP) surgeries and is strongly associated with incomplete resection. During surgery, it is technically challenging to visualize and resect all SNIP tissue in this anatomically complex area. Proteins that are overexpressed in SNIP, such as vascular endothelial growth factor (VEGF), may serve as a target for fluorescence molecular imaging to guide surgical removal of SNIP. A proof-of-concept study was performed to investigate if the VEGF-targeted near-infrared fluorescent tracer bevacizumab-800CW specifically localizes in SNIP and whether it could be used as a clinical tool to guide SNIP surgery. METHODS: In five patients diagnosed with SNIP, 10 mg of bevacizumab-800CW was intravenously administered 3 days prior to surgery. Fluorescence molecular imaging was performed in vivo during surgery and ex vivo during the processing of the surgical specimen. Fluorescence signals were correlated with final histopathology and VEGF-A immunohistochemistry. We introduced a fluorescence grid analysis to assess the fluorescence signal in individual tissue fragments, due to the nature of the surgical procedure (i.e., piecemeal resection) allowing the detection of small SNIP residues and location of the tracer ex vivo. RESULTS: In all patients, fluorescence signal was detected in vivo during endoscopic SNIP surgery. Using ex vivo fluorescence grid analysis, we were able to correlate bevacizumab-800CW fluorescence of individual tissue fragments with final histopathology. Fluorescence grid analysis showed substantial variability in mean fluorescence intensity (FImean), with SNIP tissue showing a median FImean of 77.54 (IQR 50.47-112.30) compared to 35.99 (IQR 21.48-57.81) in uninvolved tissue (p < 0.0001), although the diagnostic ability was limited with an area under the curve of 0.78. CONCLUSIONS: A fluorescence grid analysis could serve as a valid method to evaluate fluorescence molecular imaging in piecemeal surgeries. As such, although substantial differences were observed in fluorescence intensities, VEGF-A may not be the ideal target for SNIP surgery. TRIAL REGISTRATION: NCT03925285.

Targeted optical fluorescence imaging: a meta-narrative review and future perspectives.

PURPOSE: The aim of this review is to give an overview of the current status of targeted optical fluorescence imaging in the field of oncology, cardiovascular, infectious and inflammatory diseases to further promote clinical translation. METHODS: A meta-narrative approach was taken to systematically describe the relevant literature. Consecutively, each field was assigned a developmental stage regarding the clinical implementation of optical fluorescence imaging. RESULTS: Optical fluorescence imaging is leaning towards clinical implementation in gastrointestinal and head and neck cancers, closely followed by pulmonary, neuro, breast and gynaecological oncology. In cardiovascular and infectious disease, optical imaging is in a less advanced/proof of concept stage. CONCLUSION: Targeted optical fluorescence imaging is rapidly evolving and expanding into the clinic, especially in the field of oncology. However, the imaging modality still has to overcome some major challenges before it can be part of the standard of care in the clinic, such as the provision of pivotal trial data. Intensive multidisciplinary (pre-)clinical joined forces are essential to overcome the delivery of such compelling phase III registration trial data and subsequent regulatory approval and reimbursement hurdles to advance clinical implementation of targeted optical fluorescence imaging as part of standard practice.

Exploiting metabolic acidosis in solid cancers using a tumor-agnostic pH-activatable nanoprobe for fluorescence-guided surgery.

Cancer cell metabolism leads to a uniquely acidic microenvironment in solid tumors, but exploiting the labile extracellular pH differences between cancer and normal tissues for clinical use has been challenging. Here we describe the clinical translation of ONM-100, a nanoparticle-based fluorescent imaging agent. This is comprised of an ultra-pH sensitive amphiphilic polymer, conjugated with indocyanine green, which rapidly and irreversibly dissociates to fluoresce in the acidic extracellular tumor microenvironment due to the mechanism of nanoscale macromolecular cooperativity. Primary outcomes were safety, pharmacokinetics and imaging feasilibity of ONM-100. Secondary outcomes were to determine a range of safe doses of ONM-100 for intra-operative imaging using commonly used fluorescence camera systems. In this study (Netherlands National Trial Register #7085), we report that ONM-100 was well tolerated, and four solid tumor types could be visualized both in- and ex vivo in thirty subjects. ONM-100 enables detection of tumor-positive resection margins in 9/9 subjects and four additional otherwise missed occult lesions. Consequently, this pH-activatable optical imaging agent may be clinically beneficial in differentiating previously unexploitable narrow physiologic differences.

Identifying Biomarkers in Lymph Node Metastases of Esophageal Adenocarcinoma for Tumor-Targeted Imaging.

INTRODUCTION: Tumor-targeted imaging is a promising technique for the detection of lymph node metastases (LNM) and primary tumors. It remains unclear which biomarker is the most suitable target to distinguish malignant from healthy tissue in esophageal adenocarcinoma (EAC). OBJECTIVE: We performed an immunohistochemistry study to identify viable tumor markers for tumor-targeted imaging of EAC. METHODS: We used samples from 72 patients with EAC to determine the immunohistochemical expression of ten potential tumor biomarkers for EAC (carbonic anhydrase IX [CA-IX], carcinoembryonic antigen [CEA], hepatic growth factor receptor, epidermal growth factor receptor, epithelial membrane antigen [EMA], epithelial cell adhesion molecule [EpCAM], human epidermal growth factor receptor 2 [HER-2], urokinase plasminogen activator receptor, vascular endothelial growth factor-A [VEGF-A], and VEGF receptor 2). Immunohistochemistry was performed on tissue microarrays of LNM (n = 48), primary EACs (n = 62), fibrotic tissues (n = 11), nonmalignant lymph nodes (n = 24), and normal esophageal and gastric tissues (n = 40). Tumor marker staining was scored on intensity and percentage of positive cells. RESULTS: EMA and EpCAM showed strong expression in LNM (> 95%) and primary EACs (> 95%). Significant expression was also observed for LNM and EAC using VEGF-A (85 and 92%), CEA (68 and 54%), and CA-IX (4 and 34%). The other tumor biomarkers showed expression of 0-15% for LNM and primary EAC. Except for VEGF-A, nonmalignant lymph node staining was scored as slight or absent. CONCLUSIONS: High expression rates and correlation between LNM in EAC combined with low expression rates in healthy lymph nodes and esophagus tissues were observed for EpCAM and CEA, meaning these are promising targets for tumor-targeted imaging approaches for lymph nodes in patients with EAC.

Role of diagnostic laparoscopy in patients with suspicion of colorectal peritoneal metastases to evaluate suitability for cytoreductive surgery with hyperthermic intraperitoneal chemotherapy.

Background: The aim of the present study was to determine the feasibility and safety of performing diagnostic laparoscopy (DLS) routinely in patients with suspicion of colorectal peritoneal metastases (PM) to evaluate suitability for cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). Methods: Data for consecutive patients who underwent DLS between 2012 and 2018 were extracted retrospectively from an institutional database. The primary outcome was the degree of visibility of the abdominal cavity during DLS. Good laparoscopic evaluation of the abdominal cavity was defined as visibility of at least the regions of the diaphragm, pelvis and small bowel. Secondary outcomes were reasons for perioperative exclusion for CRS + HIPEC, major postoperative complications (Clavien-Dindo grade III or above) and difference in overall survival (OS) between patients deemed suitable or unsuitable for CRS + HIPEC. Kaplan-Meier analyses were performed. Results: Some 184 patients were analysed. Good laparoscopic evaluation was possible in 138 patients (75·0 per cent), and 24 (13·0 per cent) had conversion to an open procedure. Ninety-three patients (50·5 per cent) were excluded for CRS + HIPEC, most commonly because of absence of colorectal PM (34 patients, 37 per cent) or extensive disease (Peritoneal Cancer Index 20 or above) (33 patients, 35 per cent). Major complications occurred in five patients (2·7 per cent), with no postoperative deaths. Median OS was significantly decreased in patients who were excluded due to extensive disease (14 (95 per cent c.i. 10 to 18) months) compared with patients suitable for CRS + HIPEC (36 (27 to 45) months) (P < 0·001). Conclusion: Routinely performing DLS in patients with suspicion of colorectal PM to evaluate suitability for CRS + HIPEC is feasible and safe, avoiding the morbidity of an unnecessary laparotomy in patients with extensive disease.

Antecedentes: El objetivo del presente estudio fue determinar la viabilidad y seguridad de realizar una laparoscopia diagnóstica (diagnostic laparoscopy, DLS) de rutina en pacientes con sospecha de metástasis peritoneal (peritoneal metastasis, PM) de origen colorrectal para evaluar la idoneidad para la cirugía citorreductora con quimioterapia intraperitoneal hipertérmica (cytoreductive surgery + hyperthermic intraperitoneal chemotherapy, CRS+HIPEC). Métodos: Los datos de los pacientes consecutivos que fueron sometidos a DLS entre 2012 y 2018 se obtuvieron retrospectivamente de una base de datos institucional. La visualización de al menos las regiones de los diafragmas, pelvis e intestino delgado se definió como una correcta evaluación laparoscópica de la cavidad abdominal. Los resultados secundarios fueron las complicaciones postoperatorias mayores (Clavien­Dindo grado ≥ III), razones para la exclusión perioperatoria para CRS+HIPEC y diferencia en supervivencia global (overall survival, OS) entre pacientes que se consideraron apropiados y no apropiados para CRS+HIPEC. Se realizaron análisis de Kaplan­Meier y análisis de riesgos proporcionales. Resultados: Se analizaron 181 pacientes. En 138 pacientes (75,0%) fue posible una adecuada evaluación laparoscópica, mientras que 24 casos (13%) fueron convertidos a un procedimiento abierto. Se excluyeron 93 (50,5%) pacientes para CRS+HIPEC, más comúnmente por la ausencia de PM colorrectales (36,6%) o enfermedad extensa (37,6%). En cinco pacientes aparecieron complicaciones mayores (2,7%), sin mortalidad postoperatoria. La mediana de la OS disminuyó de forma significativa en pacientes que fueron excluidos debido a enfermedad extensa (14 meses, i.c. del 95% 10­18) en comparación con pacientes idóneos para CRS+HIPEC (35 meses, i.c. del 95% 30­40, P < 0,0001). Conclusión: La realización rutinaria de DLS en pacientes con sospecha de PM de origen colorrectal para evaluar la idoneidad de la CRS+HIPEC es viable y segura. La morbilidad de una laparotomía innecesaria puede prevenirse en pacientes con enfermedad extensa o ausencia de PM colorrectales.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy versus palliative systemic chemotherapy in stomach cancer patients with peritoneal dissemination, the study protocol of a multicentre randomised controlled trial (PERISCOPE II).

BACKGROUND: At present, palliative systemic chemotherapy is the standard treatment in the Netherlands for gastric cancer patients with peritoneal dissemination. In contrast to lymphatic and haematogenous dissemination, peritoneal dissemination may be regarded as locoregional spread of disease. Administering cytotoxic drugs directly into the peritoneal cavity has an advantage over systemic chemotherapy since high concentrations can be delivered directly into the peritoneal cavity with limited systemic toxicity. The combination of a radical gastrectomy with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promising results in patients with gastric cancer in Asia. However, the results obtained in Asian patients cannot be extrapolated to Western patients. The aim of this study is to compare the overall survival between patients with gastric cancer with limited peritoneal dissemination and/or tumour positive peritoneal cytology treated with palliative systemic chemotherapy, and those treated with gastrectomy, CRS and HIPEC after neoadjuvant systemic chemotherapy. METHODS: In this multicentre randomised controlled two-armed phase III trial, 106 patients will be randomised (1:1) between palliative systemic chemotherapy only (standard treatment) and gastrectomy, CRS and HIPEC (experimental treatment) after 3-4 cycles of systemic chemotherapy.Patients with gastric cancer are eligible for inclusion if (1) the primary cT3-cT4 gastric tumour including regional lymph nodes is considered to be resectable, (2) limited peritoneal dissemination (Peritoneal Cancer Index < 7) and/or tumour positive peritoneal cytology are confirmed by laparoscopy or laparotomy, and (3) systemic chemotherapy was given (prior to inclusion) without disease progression. DISCUSSION: The PERISCOPE II study will determine whether gastric cancer patients with limited peritoneal dissemination and/or tumour positive peritoneal cytology treated with systemic chemotherapy, gastrectomy, CRS and HIPEC have a survival benefit over patients treated with palliative systemic chemotherapy only. TRIAL REGISTRATION: clinicaltrials.gov NCT03348150 ; registration date November 2017; first enrolment November 2017; expected end date December 2022; trial status: Ongoing.

SSTR-2 as a potential tumour-specific marker for fluorescence-guided meningioma surgery.

BACKGROUND: Meningiomas are the most frequently occurring primary intracranial tumours in adults. Surgical removal can only be curative by complete resection; however surgical access can be challenging due to anatomical localization and local invasion of bone and soft tissues. Several intraoperative techniques have been tried to improve surgical resection, including intraoperative fluorescence guided imaging; however, no meningioma-specific (fluorescent) targeting has been developed yet. Here, we aimed to identify the most promising biomarkers for targeted intra-operative fluorescence guided meningioma surgery. METHODS: One hundred forty-eight meningioma specimens representing all meningioma grades were analysed using immunohistochemistry (IHC) on tissue microarrays (TMAs) to determine expression patterns of meningioma biomarkers epithelial membrane antigen (EMA), platelet-derived growth factor ß (PDGF-ß), vascular endothelial growth factor α (VEGF-α), and somatostatin receptor type 2 (SSTR-2). Subsequently, the most promising biomarker was selected based on TArget Selection Criteria (TASC). Marker expression was examined by IHC in 3D cell culture models generated from freshly resected tumour material. RESULTS: TMA-IHC showed strongest staining for SSTR-2. All cases were positive, with 51.4% strong/diffuse, 30.4% moderate/diffuse and only 18.2% focal/weak staining patterns. All tested biomarkers showed at least weak positivity in all meningiomas, regardless of WHO grade. TASC analysis showed that SSTR-2 was the most promising target for fluorescence guided imaging, with a total score of 21 (out of 22). SSTR-2 expression was determined on original patient tumours and 3D cultures of three established cultures. CONCLUSIONS: SSTR-2 expression was highly sensitive and specific in all 148 meningiomas, regardless of WHO grade. According to TASC analysis, SSTR-2 is the most promising receptor for meningioma targeting. After establishing in vitro meningioma models, SSTR-2 cell membrane expression was confirmed in two of three meningioma cultures as well. This indicates that specific fluorescence in an experimental setting can be performed for the further development of targeted fluorescence guided meningioma surgery and near-infrared fluorescent tracers targeting SSTR-2.

A systematic review and meta-analyses of sentinel lymph node identification in breast cancer and melanoma, a plea for tracer mapping.

PURPOSE: Sentinel lymph node biopsy (SLNB) has become a widely accepted staging procedure for both breast carcinoma and melanoma. The aim of our study was to systematically review different SLNB techniques and perform a meta-analysis for corresponding identification and false-negative rates. METHODS: A systematic review of the literature on SLNB in patients with early stage breast carcinoma and melanoma was performed. Only original study groups were included. The SLN identification rate and false negative rate were pooled for patients with breast carcinoma or melanoma according to radiocolloid tracer, blue dye, indocyanine green (ICG), or a combination of a radiocolloid tracer with blue dye or ICG. RESULTS: Between 1992 and 2012, a total of 154 studies (88 breast carcinoma and 66 melanoma) were reported that met our eligibility criteria. These studies included a total of 44,172 patients. The pooled SLN identification rate in breast carcinoma and melanoma patients using solely blue dye was 85% (range: 65-100%) and 84% (range: 59-100%), while for radiocolloid alone it was 94% (range: 67-100%) and 99% (range: 83-100%), respectively. Using a combination of radiocolloid and blue, identification rates were 95% (range 94-95%) and 98% (range: 98-98%). CONCLUSIONS: The current meta-analysis provides data that favors the use of radiocolloid or radiocolloid combined with a blue dye for SLN identification. Performing SLNB with radiocolloid alone is the technique of choice for experienced surgeons, since blue dye has multiple disadvantages. SLNB using ICG as a fluorescent dye seems a promising technique for the near future.

Optical innovations in surgery.

BACKGROUND: In the past decade, there has been a major drive towards clinical translation of optical and, in particular, fluorescence imaging in surgery. In surgical oncology, radical surgery is characterized by the absence of positive resection margins, a critical factor in improving prognosis. Fluorescence imaging provides the surgeon with reliable and real-time intraoperative feedback to identify surgical targets, including positive tumour margins. It also may enable decisions on the possibility of intraoperative adjuvant treatment, such as brachytherapy, chemotherapy or emerging targeted photodynamic therapy (photoimmunotherapy). METHODS: This article reviews the use of optical imaging for intraoperative guidance and decision-making. RESULTS: Image-guided cancer surgery has the potential to be a powerful tool in guiding future surgical care. Photoimmunotherapy is a theranostic concept (simultaneous diagnosis and treatment) on the verge of clinical translation, and is highlighted as an effective combination of image-guided surgery and intraoperative treatment of residual disease. Multispectral optoacoustic tomography, a technique complementary to optical image-guided surgery, is currently being tested in humans and is anticipated to have great potential for perioperative and postoperative application in surgery. CONCLUSION: Significant advances have been achieved in real-time optical imaging strategies for intraoperative tumour detection and margin assessment. Optical imaging holds promise in achieving the highest percentage of negative surgical margins and in early detection of micrometastastic disease over the next decade.

Towards a successful clinical implementation of fluorescence-guided surgery.

During the European Molecular Imaging Meeting (EMIM) 2013, the fluorescence-guided surgery study group held its inaugural session to discuss the clinical implementation of fluorescence-guided surgery. The general aim of this study group is to discuss and identify the steps required to successfully and safely bring intraoperative fluorescence imaging to the clinics. The focus group intends to use synergies between interested groups as a tool to address regulatory and implementation hurdles in Europe and operates within the intraoperative focus group of the World Molecular Imaging Society (WMIS) that promotes the same interests at the WMIS level. The major topics on the critical path of implementation identified within the study group were quality controls and standards for ensuring accurate imaging and the ability to compare results from different studies, regulatory affairs, and strategies to increase awareness among physicians, regulators, insurance companies, and a broader audience. These hurdles, and the possible actions discussed to overcome them, are summarized in this report. Furthermore, a number of recommendations for the future shape of the fluorescence-guided study group are discussed. A main driving conclusion remains that intraoperative imaging has great clinical potential and that many of the solutions required are best addressed with the community working together to optimally promote and accelerate the clinical implementation of fluorescence imaging towards improving surgical procedures.

Real-time near infrared fluorescence (NIRF) intra-operative imaging in ovarian cancer using an α(v)ß(3-)integrin targeted agent.

BACKGROUND: In ovarian cancer, optimal cytoreductive surgery is of the utmost importance for long-term survival. The ability to visualize minuscule tumor deposits is important to ensure complete resection of the tumor. The purpose of our study was to estimate the in vivo sensitivity, specificity and diagnostic accuracy of an intra-operative fluorescence imaging system combined with an α(v)ß(3)-integrin targeted near-infrared fluorescent probe. METHOD: Tumor bearing mice were injected intravenously with a fluorescent probe targeting α(v)ß(3) integrins. Fluorescent spots and non-fluorescent tissue were identified and resected. Standard histopathology and fluorescence microscopy were used as gold-standard for tumor detection. RESULTS: Fifty-eight samples excised with support of intra-operative image-guided surgery were analyzed. The mean target to background ratio was 2.2 (SD 0.5). The calculated sensitivity of the imaging system was 95%, and the specificity was 88% with a diagnostic accuracy of 96.5%. CONCLUSION: Near-infrared image-guided surgery in this model has a high diagnostic accuracy and a fair target to background ratio that supports the development towards clinical translation of α(v)ß(3)-integrin targeted imaging.

Documenting correct assessment of biliary anatomy during laparoscopic cholecystectomy.

BACKGROUND: Correct assessment of biliary anatomy can be documented by photographs showing the "critical view of safety" (CVS) but also by intraoperative cholangiography (IOC). METHODS: Photographs of the CVS and IOC images for 63 patients were presented to three expert observers in a random and blinded fashion. The observers answered questions pertaining to whether the biliary anatomy had been conclusively documented. RESULTS: The CVS photographs were judged to be "conclusive" in 27%, "probable" in 35%, and "inconclusive" in 38% of the cases. The IOC images performed better and were judged to be "conclusive" in 57%, "probable" in 25%, and "inconclusive" in 18% of the cases (P < 0.001 compared with the photographs). The observers indicated that they would feel comfortable transecting the cystic duct based on the CVS photographs in 52% of the cases and based on the IOC images in 73% of the cases (P = 0.004). The interobserver agreement was moderate for both methods (kappa values, 0.4-0.5). For patients with a history of cholecystitis, both the CVS photographs and the IOC images were less frequently judged to be sufficient for transection of the cystic duct (P = 0.006 and 0.017, respectively). CONCLUSION: In this series, IOC was superior to photographs of the CVS for documentation of the biliary anatomy during laparoscopic cholecystectomy. However, both methods were judged to be conclusive only for a limited proportion of patients, especially in the case of cholecystitis. This study highlights that documenting assessment of the biliary anatomy is not as straightforward as it seems and that protocols are necessary, especially if the images may be used for medicolegal purposes. Documentation of the biliary anatomy should be addressed during training courses for laparoscopic surgery.

Safety measures during cholecystectomy: results of a nationwide survey.

BACKGROUND: This study aimed to identify safety measures practiced by Dutch surgeons during laparoscopic cholecystectomy. METHOD: An electronic questionnaire was sent to all members of the Dutch Society of Surgery with a registered e-mail address. RESULTS: The response rate was 40.4% and 453 responses were analyzed. The distribution of the respondents with regard to type of hospital was similar to that in the general population of Dutch surgeons. The critical view of safety (CVS) technique is used by 97.6% of the surgeons. It is documented by 92.6%, mostly in the operation report (80.0%), but often augmented by photography (42.7%) or video (30.2%). If the CVS is not obtained, 50.9% of surgeons convert to the open approach, 39.1% continue laparoscopically, and 10.0% perform additional imaging studies. Of Dutch surgeons, 53.2% never perform intraoperative cholangiography (IOC), 41.3% perform it incidentally, and only 2.6% perform it routinely. A total of 105 bile duct injuries (BDIs) were reported in 14,387 cholecystectomies (0.73%). The self-reported major BDI rate (involving the common bile duct) was 0.13%, but these figures need to be confirmed in other studies. CONCLUSION: The CVS approach in laparoscopic cholecystectomy is embraced by virtually all Dutch surgeons. The course of action when CVS is not obtained varies. IOC seems to be an endangered skill as over half the Dutch surgeons never perform it and the rest perform it only incidentally.

Intraoperative near-infrared fluorescence imaging for sentinel lymph node detection in vulvar cancer: first clinical results.

OBJECTIVE: Disadvantages of the combined sentinel lymph node (SLN) procedure with radiocolloid and blue dye in vulvar cancer are the preoperative injections of radioactive tracer in the vulva, posing a painful burden on the patient. Intraoperative transcutaneous imaging of a peritumorally injected fluorescent tracer may lead to a one-step procedure, while maintaining high sensitivity. Aim of this pilot study was to investigate the applicability of intraoperative fluorescence imaging for SLN detection and transcutaneous lymphatic mapping in vulvar cancer. METHODS: Ten patients with early stage squamous cell carcinoma of the vulva underwent the standard SLN procedure. Additionally, a mixture of 1 mL patent blue and 1 mL indocyanin green (ICG; 0.5 mg/mL) was injected immediately prior to surgery, with the patient under anesthesia. Color and fluorescence images and videos of lymph flow were acquired using a custom-made intraoperative fluorescence camera system. The distance between skin and femoral artery was determined on preoperative CT-scan as a measure for subcutaneous adipose tissue. RESULTS: In 10 patients, SLNs were detected in 16 groins (4 unilateral; 6 midline tumors). Transcutaneous lymphatic mapping was possible in five patients (5 of 16 groins), and was limited to lean patients, with a maximal distance between femoral artery and skin of 24 mm, as determined on CT. In total, 29 SLNs were detected by radiocolloid, of which 26 were also detected by fluorescence and 21 were blue. CONCLUSIONS: These first clinical results indicate that intraoperative transcutaneous lymphatic mapping using fluorescence is technically feasible in a subgroup of lean vulvar cancer patients.

Near-infrared fluorescence (NIRF) imaging in breast-conserving surgery: assessing intraoperative techniques in tissue-simulating breast phantoms.

PURPOSE: Breast-conserving surgery (BCS) results in tumour-positive surgical margins in up to 40% of the patients. Therefore, new imaging techniques are needed that support the surgeon with real-time feedback on tumour location and margin status. In this study, the potential of near-infrared fluorescence (NIRF) imaging in BCS for pre- and intraoperative tumour localization, margin status assessment and detection of residual disease was assessed in tissue-simulating breast phantoms. METHODS: Breast-shaped phantoms were produced with optical properties that closely match those of normal breast tissue. Fluorescent tumour-like inclusions containing indocyanine green (ICG) were positioned at predefined locations in the phantoms to allow for simulation of (i) preoperative tumour localization, (ii) real-time NIRF-guided tumour resection, and (iii) intraoperative margin assessment. Optical imaging was performed using a custom-made clinical prototype NIRF intraoperative camera. RESULTS: Tumour-like inclusions in breast phantoms could be detected up to a depth of 21 mm using a NIRF intraoperative camera system. Real-time NIRF-guided resection of tumour-like inclusions proved feasible. Moreover, intraoperative NIRF imaging reliably detected residual disease in case of inadequate resection. CONCLUSION: We evaluated the potential of NIRF imaging applications for BCS. The clinical setting was simulated by exploiting tissue-like breast phantoms with fluorescent tumour-like agarose inclusions. From this evaluation, we conclude that intraoperative NIRF imaging is feasible and may improve BCS by providing the surgeon with imaging information on tumour location, margin status, and presence of residual disease in real-time. Clinical studies are needed to further validate these results.

Bioluminescence as gold standard for validation of optical imaging modalities in peritoneal carcinomatosis animal models.

BACKGROUND: The outcome of cytoreductive surgery in patients with peritoneal carcinomatosis is influenced by incomplete resection as a result of inadequate detection of a tumor, i.e. residual disease. The future perspective of complete resection, made possible by application of intraoperative near-infrared fluorescence imaging (NIRF), led to the development and validation of a bioluminescent colorectal peritoneal carcinomatosis xenograft rat model to act as the gold standard for the evaluation of new optical imaging modalities. METHODS: Twenty nude rats were inoculated intraperitoneally with 2 × 10(6) luciferase-labeled human colorectal tumor cells (HT-29-luc-D6). The peritoneal carcinomatosis index (PCI) was estimated using visual observation (PCI-VO) and VO combined with bioluminescence imaging (PCI-BLI). Subsequently, the BL images were presented, and residual tumor tissue was localized by PCI-BLI scoring and compared with the PCI-VO. RESULTS: BLI revealed additional tumor tissue, confirmed by HE staining, compared to VO alone in 7 out of 8 rats (p < 0.02). CONCLUSION: The developed model turned out to be suitable. The use of BLI for tumor detection was more sensitive compared to VO alone. In this model, BLI significantly detected residual disease, and therefore, BLI can be denominated as the gold standard for the evaluation of optical imaging modalities like NIRF.

Sentinel node mapping with indocyanine green (ICG) and infrared ray detection in early gastric cancer: an accurate method that enables a limited lymphadenectomy.

AIM: This study compares lymphatic mapping in early gastric cancer with ICG and infrared ray electronic endoscopy (IREE) to ICG alone. It examines the optimal method for intra-operative detection of metastases and shows long term follow up results. METHODS: 212 patients underwent the SN procedure with IREE and peritumoural ICG injection. Evaluated parameters were detection of sentinel nodes with IREE versus ICG alone, intra-operative detection rate of lymph node (LN) metastasis with node picking versus lymphatic basin dissection (LBD) and lymphatic drainage patterns. RESULTS: 34 patients had LN metastases. The SN identification rate and sensitivity for IREE versus ICG alone were 99.5 versus 85.8% and 97.0 versus 48.4% respectively. Intra-operative accuracy for detecting LN metastasis was 50% with node picking versus 92.3% with LBD. LN metastases were always in the SN basin. Lymphatic invasion and T-stage were risk factors for nodal metastases. Two patients showed recurrent disease. Both had a tumour with signet cell differentiation. One patient had a T3 tumour, the other patient had a tumour with a diameter of 85 mm. CONCLUSION: The SN procedure with IREE can detect the SN and is better than ICG alone. LBD of the SN basin is required for accurate intra-operative diagnosis of metastases. LBD dissection based on IREE is a safe method of nodal dissection in patients with T1 or limited T2 tumours.

Impact of 18-fluorodeoxyglucose positron emission tomography on computed tomography defined target volumes in radiation treatment planning of esophageal cancer: reduction in geographic misses with equal inter-observer variability: PET/CT improves esophageal target definition.

Target volume definition in modern radiotherapy is based on planning computed tomography (CT). So far, 18-fluorodeoxyglucose positron emission tomography (FDG-PET) has not been included in planning modality in volume definition of esophageal cancer. This study evaluates fusion of FDG-PET and CT in patients with esophageal cancer in terms of geographic misses and inter-observer variability in volume definition. In 28 esophageal cancer patients, gross, clinical and planning tumor volumes (GTV; CTV; PTV) were defined on planning CT by three radiation oncologists. After software-based emission tomography and computed tomography (PET/CT) fusion, tumor delineations were redefined by the same radiation-oncologists. Concordance indexes (CCI's) for CT and PET/CT based GTV, CTV and PTV were calculated for each pair of observers. Incorporation of PET/CT modified tumor delineation in 17/28 subjects (61%) in cranial and/or caudal direction. Mean concordance indexes for CT-based CTV and PTV were 72 (55-86)% and 77 (61-88)%, respectively, vs. 72 (47-99)% and 76 (54-87)% for PET/CT-based CTV and PTV. Paired analyses showed no significant difference in CCI between CT and PET/CT. Combining FDG-PET and CT may improve target volume definition with less geographic misses, but without significant effects on inter-observer variability in esophageal cancer.