Preoperative radiation therapy increases adherence in patients with high-risk extremity soft tissue sarcoma.

BACKGROUND: Surgery and radiation therapy remain the standard of care for patients with high-grade extremity soft tissue sarcoma that are >5 cm. Radiation therapy is time and labor-intensive for patients, and social determinants of health may affect adherence. The aim of this study was to define demographic, clinical, and treatment factors associated with the completion of radiation therapy and determine if preoperative radiation therapy improved adherence compared to postoperative radiation therapy. METHODS: The cohort included patients in the National Cancer Database with high-grade extremity soft tissue sarcoma >5 cm without nodal or distant metastases who received limb-sparing surgery and radiation therapy with microscopically negative R0 margins. Multivariable logistic regression analyses identified factors associated with radiation therapy sequencing and adherence (defined as completion of 50 Gy preoperative radiation therapy or at least 60 Gy postoperative radiation therapy). A multivariable Cox Proportional Hazards model assessed overall survival. RESULTS: Among 2,145 patients, 47.1% received preoperative radiation therapy (n = 1,010), and 52.9% (n = 1135) received postoperative radiation therapy. A greater proportion of patients treated with preoperative (77.2%) versus postoperative radiation therapy (64.9%, P < .0001) received the recommended dose. More patients with private insurance (49.8% vs 35.3% Medicaid vs 44.9% Medicare, P = .011) and patients treated at an academic medical center (52.6% vs 47.4%, P < .001) received preoperative radiation therapy. Patients who received preoperative radiation therapy had lower odds of receiving insufficient doses of radiation therapy (odds ratio 0.34 [95% CI 0.27-0.47]). Neither radiation therapy adherence nor sequencing were independent predictors of overall survival. CONCLUSIONS: Patients who received preoperative radiation therapy were more likely to complete therapy and receive an optimal dose than patients treated with postoperative radiation therapy. Preoperative radiation therapy improves adherence and should be widely considered in patients with high-grade extremity soft tissue sarcoma, particularly in patients at risk for not completing therapy.

Prognostic factors in patients receiving surgery and radiation therapy for retroperitoneal sarcoma: A machine-learning analysis.

BACKGROUND: The addition of radiation therapy to surgery for retroperitoneal sarcoma remains controversial. Improved patient selection may help identify optimal candidates for multimodality treatment. The aim of this analysis was to define prognostic factors among patients who receive radiation therapy and surgery to aid in patient selection for multimodal therapy. METHODS: Patients who received radiation therapy and underwent curative-intent resection for retroperitoneal sarcoma between 2004 and 2016 were identified from a national cohort in the United States (National Cancer Database). A machine-based classification and regression tree model was used to generate similar groups of patients relative to overall survival based on preoperative factors. RESULTS: A total of 1,443 patients received radiation therapy in addition to surgery. Median age was 61 years old and 55.0% were female. Most patients (66%) received care at an academic or integrated network cancer program. With a median follow-up of 84 months, receipt of radiation therapy was not associated with improved overall survival (P = .81). Classification and regression tree analysis revealed a significant association between overall survival and American Joint Committee on Cancer stage group, age, tumor histology, and Charlson comorbidity score. Application of these parameters via machine learning stratified patients into 5 cohorts with distinct survival outcomes. In the most favorable cohort (Cohort 1: American Joint Committee on Cancer stage group ≤II, age ≤61, histology including fibrosarcoma, well differentiated liposarcoma, myxoid liposarcoma, and leiomyosarcoma), the 5-year overall survival was 81.7% and median overall survival was not reached; in the least favorable cohort (Cohort 6: American Joint Committee on Cancer stage group >II, age >68) where the 5-year survival was 41.3% and median overall survival was 45.2 months (P < .001 versus Cohort 1). CONCLUSION: In the absence of a defined survival benefit, patients with advanced American Joint Committee on Cancer stage group, older age, and medical comorbidities have relatively unfavorable overall survival after combined modality therapy and therefore stand the least to gain from the addition of radiation therapy to surgery. In contrast, younger patients with good performance status and retroperitoneal sarcoma histologies with a higher propensity for local recurrence may have the greatest opportunity to benefit from radiation therapy.

Characterizing the patient experience during neoadjuvant therapy for pancreatic ductal adenocarcinoma: A qualitative study.

BACKGROUND: Neoadjuvant therapy (NT) has increasingly been utilized for patients with localized pancreatic ductal adenocarcinoma (PDAC). It is the recommended approach for borderline resectable (BR) and locally advanced (LA) cancers and an increasingly utilized option for potentially resectable (PR) disease. Despite its increased use, little research has focused on patient-centered metrics among patients undergoing NT, including patient experiences, preferences, and recommendations. A better understanding of all aspects of the patient experience during NT may identify opportunities to design interventions aimed at improving quality of life; it may also facilitate the completion of NT and receipt of surgery, ultimately optimizing long-term outcomes. AIM: To understand the experience of patients initiating and receiving NT to identify opportunities to improve neoadjuvant cancer care delivery. METHODS: Semi-structured interviews of patients with localized PDAC during NT were conducted to explore their experience initiating and receiving NT. Interviews took place between August 2020 and October 2021. Due to the descriptive nature of the research, questions were open ended. Interviews were conducted over the phone, audio recorded and then transcribed. All interviews were coded by two independent researchers using NVivo 12, iteratively identifying themes until thematic saturation was achieved. An integrative approach to qualitative analysis was used, utilizing both inductive and deductive methods. RESULTS: A total of 12 patients with localized PDAC were interviewed. Patients with BR (n = 7), PR (n = 2), and LA (n = 3) cancers participated in the study. All patients indicated that choosing NT was the doctor's recommendation, while most reported not being familiar with the concept of NT (n = 11) and that NT was presented as the only option (n = 8). Five themes describing the patient experience emerged: physical symptoms, emotional symptoms, coping mechanisms, access to care, and life factors. The most commonly cited recommendation for improving the experience of NT was improved education before and during NT (n = 7). Patients highlighted the need for more information on the rationale behind choosing NT prior to surgery, the anticipated surgery and its likelihood of surgery occurring after NT, as well as general information prior to starting NT treatment. The need for seeing different members of the healthcare team, including ancillary services was also frequently cited as a recommendation for improving the experience of NT (n = 5). CONCLUSION: This study provides a framework to allow for a better understanding of the PDAC patient experience during NT and highlights opportunities to improve quality and quantity of life outcomes.

Multi-specialty physician perspectives on barriers and facilitators to the use of neoadjuvant therapy for pancreatic ductal adenocarcinoma.

BACKGROUND: Neoadjuvant therapy (NT) is increasingly utilized for patients with localized pancreatic ductal adenocarcinoma (PDAC). Given the importance of completing multimodality therapy, the purpose of this qualitative study was to characterize physician perspectives on barriers and facilitators to delivering NT. METHODS: A purposive sample of surgical, medical, and radiation oncologists participated in semi-structured interviews. Interviews were transcribed and coded by 3 independent researchers, iteratively identifying themes until saturation was achieved. RESULTS: Participants (n = 27) were heterogeneous in specialty, years of experience, practice setting, gender, and geography. The most commonly cited advantage of NT was the ability to downstage patients. The most commonly cited barriers included lack of access and limited evidence. Patient preference for immediate surgery was frequently cited as a barrier, but most participants felt that patients eventually understood the treatment recommendation after informed discussion. Recommendations to enhance the delivery of NT included improved patient education, communication, and better evidence. CONCLUSION: In this qualitative study, indications for, barriers to, and opportunities to improve the delivery of NT for localized PDAC were identified. These results highlight the need for better evidence and protocol standardization for NT as well as methods of improving care coordination, communication, and education to improve patient-centered outcomes.

Pancreatic enzyme autodigestion of an unresectable retroperitoneal liposarcoma.

This is a case of a 71-year-old man who had multiple synchronous retroperitoneal liposarcoma (LPS) foci composed of both well-differentiated and dedifferentiated histologies. In addressing this, the patient underwent a margin negative resection of a 11.8×8.8 cm right-sided dedifferentiated LPS requiring pancreaticoduodenectomy; however, a 13.1×7.2 cm left-sided well-differentiated LPS (WDLPS) was not resected due to its involvement of the proximal mesenteric vessels. The patient's postoperative course was complicated by grade B postoperative pancreatic fistula involving the anatomical territory of the residual WDLPS. Over the next 12 months, serial CT scans demonstrated a stepwise reduction in size of the WDLPS until it completely regressed. The authors hypothesise that enzymes shed from the pancreatic fistula initiated the autodigestion and subsequent necrosis of the WDLPS with associated tumour regression.

Impact of visitor restriction rules on the postoperative experience of COVID-19 negative patients undergoing surgery.

BACKGROUND: Many hospitals have implemented visitor restriction policies in response to the coronavirus disease 2019 pandemic. Because caregivers serve an important role in postoperative recovery, the purpose of this study was to evaluate the impact of visitor restrictions on the postoperative experience of coronavirus disease 2019-negative patients undergoing surgery. METHODS: Patients who underwent surgery immediately before or after the implementation of a visitor restriction policy were enrolled. Patients were surveyed on their inpatient experience and preparedness for discharge using items adapted from validated questionnaires. RESULTS: Among 128 eligible patients, 117 agreed to participate (91.4% response rate): 58 (49.6%) in the Visitor Cohort and 59 (50.4%) in the No-Visitor Cohort. Mean age was 57.5 years (standard deviation 13.9) and 66 (56.4%) were female. Among all patients, 47.8% underwent oncologic surgery, 31.6% transplant, and 20.5% general or other. Patients in the No-Visitor Cohort were less likely to report complete satisfaction with the hospital experience (80.7% vs 66.0%, P = .044), timely receipt of medications (84.5% vs 69.0%, P = .048), and assistance getting out of bed (70.7% vs 51.7%, P = .036). No-Visitor Cohort patients were less likely to feel that their discharge preferences were adequately considered (79.3% vs 54.2%, P = .004). Qualitative analysis of patient responses highlighted the consistent psychosocial support provided by visitors after surgery (84.5%), and patients in the No-Visitor Cohort reported social isolation due to lack of psychosocial support (50.8%). CONCLUSION: The implementation of hospital visitor restriction policies may adversely impact the postoperative experience of coronavirus disease 2019-negative patients undergoing surgery. These findings highlight the urgent need for novel patient-centered strategies to improve the postoperative experience of patients during ongoing or future disruptions to routine hospital practice.

Folate Receptor Near-Infrared Optical Imaging Provides Sensitive and Specific Intraoperative Visualization of Nonfunctional Pituitary Adenomas.

BACKGROUND: Surgical resection is the primary treatment for nonfunctional (NF) pituitary adenomas, but gross-total resection is difficult to achieve in all cases. NF adenomas overexpress folate receptor alpha (FRα). OBJECTIVE: To test the hypothesis that we could target FRα for highly sensitive and specific intraoperative detection of NF adenomas using near-infrared (NIR) imaging. METHODS: Fourteen patients with NF pituitary adenoma were infused with the folate analog NIR dye OTL38 preoperatively. NIR fluorescence signal-to-background ratio (SBR) was recorded for each tumor during resection of the adenomas. Extent of surgery was not modified based on the presence or absence of fluorescence. Immunohistochemistry was performed to assess FRα expression in all specimens. Magnetic resonance imaging (MRI) was performed postoperatively to assess residual neoplasm. RESULTS: Nine adenomas overexpressed FRα and fluoresced with a NIR SBR of 3.2 ± 0.52, whereas the 5 non-FRα-overexpressing adenomas fluoresced with an SBR of 1.5 ± 0.21. Linear regression demonstrated a significant correlation between intraoperative SBR and the FRα expression (P-value < .001). Analysis of 14 margin samples revealed that the surgeon's impression of the tissue had 83% sensitivity, 100% specificity, 100% positive predictive value, and 89% negative predictive value, while NIR fluorescence had 100% for all values. NIR fluorescence accurately predicted postoperative MRI results in 78% of FRα-overexpressing patients. CONCLUSION: Preoperative injection of folate-tagged NIR dye provides strong signal and visualization of NF pituitary adenomas. It is 100% sensitive and specific for detecting margin neoplasm and can predict postoperative MRI findings. Our results suggest that NIR fluorescence may be superior to white-light visualization alone and may improve resection rates in NF pituitary adenomas.

Folate Receptor Overexpression in Human and Canine Meningiomas-Immunohistochemistry and Case Report of Intraoperative Molecular Imaging.

BACKGROUND: Meningiomas are well-encapsulated benign brain tumors and surgical resection is often curative. Nevertheless, this is not always possible due to the difficulty of identifying residual disease intraoperatively. We hypothesized that meningiomas overexpress folate receptor alpha (FRα), allowing intraoperative molecular imaging by targeting FRα with a near-infrared (NIR) dye. OBJECTIVE: To determine FRα expression in both human and canine meningioma cohorts to prepare for future clinical studies. Present a case study of a meningioma resection with intraoperative NIR fluorescence imaging. METHODS: Tissue samples of 27 human meningioma specimens and 7 canine meningioma specimens were immunohistochemically stained for FRα along with normal dura, skeletal muscle, and kidney tissue. We then enrolled a patient with a pituitary adenoma and tuberculum sella meningioma in a clinical trial in which the patient received an infusion of folate-linked, NIR fluorescent dye prior to surgery. RESULTS: In the cohort of human meningiomas, 9 WHO grade I, 12 grade II, and 6 grade III tumors were identified. Eighty-nine percent of WHO grade I, 67% of grade II, and 50% of grade III tumors overexpressed FRα. In the 7 canine meningioma samples, 100% stained positively for FRα. Both human and canine normal dura from autopsy samples demonstrated no evidence of FRα overexpression. In the case study, the meningioma demonstrated a high NIR signal-to-background-ratio of 4.0 and demonstrated strong FRα immunohistochemistry staining. CONCLUSION: This study directly demonstrates FRα overexpression in both human and canine meningiomas. We also demonstrate superb intraoperative imaging of a meningioma using a FRα-targeting dye.

Folate receptor overexpression can be visualized in real time during pituitary adenoma endoscopic transsphenoidal surgery with near-infrared imaging.

OBJECTIVE Pituitary adenomas account for approximately 10% of intracranial tumors and have an estimated prevalence of 15%-20% in the general US population. Resection is the primary treatment for pituitary adenomas, and the transsphenoidal approach remains the most common. The greatest challenge with pituitary adenomas is that 20% of patients develop tumor recurrence. Current approaches to reduce recurrence, such as intraoperative MRI, are costly, associated with high false-positive rates, and not recommended. Pituitary adenomas are known to overexpress folate receptor alpha (FRα), and it was hypothesized that OTL38, a folate analog conjugated to a near-infrared (NIR) fluorescent dye, could provide real-time intraoperative visual contrast of the tumor versus the surrounding nonneoplastic tissues. The preliminary results of this novel clinical trial are presented. METHODS Nineteen adult patients who presented with pituitary adenoma were enrolled. Patients were infused with OTL38 2-4 hours prior to surgery. A 4-mm endoscope with both visible and NIR light capabilities was used to visualize the pituitary adenoma and its margins in real time during surgery. The signal-to-background ratio (SBR) was recorded for each tumor and surrounding tissues at various endoscope-to-sella distances. Immunohistochemical analysis was performed to assess the FRα expression levels in all specimens and classify patients as having either high or low FRα expression. RESULTS Data from 15 patients (4 with null cell adenomas, 1 clinically silent gonadotroph, 1 totally silent somatotroph, 5 with a corticotroph, 3 with somatotrophs, and 1 somatocorticotroph) were analyzed in this preliminary analysis. Four patients were excluded for technical considerations. Intraoperative NIR imaging delineated the main tumors in all 15 patients with an average SBR of 1.9 ± 0.70. The FRα expression level of the adenomas and endoscope-to-sella distance had statistically significant impacts on the fluorescent SBRs. Additional considerations included adenoma functional status and time from OTL38 injection. SBRs were 3.0 ± 0.29 for tumors with high FRα expression (n = 3) and 1.6 ± 0.43 for tumors with low FRα expression (n = 12; p < 0.05). In 3 patients with immunohistochemistry-confirmed FRα overexpression (2 patients with null cell adenoma and 1 patient with clinically silent gonadotroph), intraoperative NIR imaging demonstrated perfect classification of the tumor margins with 100% sensitivity and 100% specificity. In addition, for these 3 patients, intraoperative residual fluorescence predicted postoperative MRI results with perfect concordance. CONCLUSIONS Pituitary adenomas and their margins can be intraoperatively visualized with the preoperative injection of OTL38, a folate analog conjugated to NIR dye. Tumor-to-background contrast is most pronounced in adenomas that overexpress FRα. Intraoperative SBR at the appropriate endoscope-to-sella distance can predict adenoma FRα expression status in real time. This work suggests that for adenomas with high FRα expression, it may be possible to identify margins and to predict postoperative MRI findings.

Near-infrared fluorescent image-guided surgery for intracranial meningioma.

OBJECTIVE Meningiomas are the most common primary tumor of the central nervous system. Complete resection can be curative, but intraoperative identification of dural tails and tumor remnants poses a clinical challenge. Given data from preclinical studies and previous clinical trials, the authors propose a novel method of localizing tumor tissue and identifying residual disease at the margins via preoperative systemic injection of a near-infrared (NIR) fluorescent contrast dye. This technique, what the authors call "second-window indocyanine green" (ICG), relies on the visualization of ICG approximately 24 hours after intravenous injection. METHODS Eighteen patients were prospectively identified and received 5 mg/kg of second-window ICG the day prior to surgery. An NIR camera was used to localize the tumor prior to resection and to inspect the margins following standard resection. The signal to background ratio (SBR) of the tumor to the normal brain parenchyma was measured in triplicate. Gross tumor and margin specimens were qualitatively reported with respect to fluorescence. Neuropathological diagnosis served as the reference gold standard to calculate the sensitivity and specificity of the imaging technique. RESULTS Eighteen patients harbored 15 WHO Grade I and 3 WHO Grade II meningiomas. Near-infrared visualization during surgery ranged from 18 to 28 hours (mean 23 hours) following second-window ICG infusion. Fourteen of the 18 tumors demonstrated a markedly elevated SBR of 5.6 ± 1.7 as compared with adjacent brain parenchyma. Four of the 18 patients showed an inverse pattern of NIR signal, that is, stronger in the adjacent normal brain than in the tumor (SBR 0.31 ± 0.1). The best predictor of inversion was time from injection, as the patients who were imaged earlier were more likely to demonstrate an appropriate SBR. The second-window ICG technique demonstrated a sensitivity of 96.4%, specificity of 38.9%, positive predictive value of 71.1%, and a negative predictive value of 87.5% for tumor. CONCLUSIONS Systemic injection of NIR second-window ICG the day before surgery can be used to visualize meningiomas intraoperatively. Intraoperative NIR imaging provides higher sensitivity in identifying meningiomas than the unassisted eye. In this study, 14 of the 18 patients with meningioma demonstrated a strong SBR compared with adjacent brain. In the future, reducing the time interval from dye injection to intraoperative imaging may improve fluorescence at the margins, though this approach requires further investigation. Clinical trial registration no.: NCT02280954 ( clincialtrials.gov ).

Comparison of Near-Infrared Imaging Camera Systems for Intracranial Tumor Detection.

PURPOSE: Distinguishing neoplasm from normal brain parenchyma intraoperatively is critical for the neurosurgeon. 5-Aminolevulinic acid (5-ALA) has been shown to improve gross total resection and progression-free survival but has limited availability in the USA. Near-infrared (NIR) fluorescence has advantages over visible light fluorescence with greater tissue penetration and reduced background fluorescence. In order to prepare for the increasing number of NIR fluorophores that may be used in molecular imaging trials, we chose to compare a state-of-the-art, neurosurgical microscope (System 1) to one of the commercially available NIR visualization platforms (System 2). PROCEDURES: Serial dilutions of indocyanine green (ICG) were imaged with both systems in the same environment. Each system's sensitivity and dynamic range for NIR fluorescence were documented and analyzed. In addition, brain tumors from six patients were imaged with both systems and analyzed. RESULTS: In vitro, System 2 demonstrated greater ICG sensitivity and detection range (System 1 1.5-251 µg/l versus System 2 0.99-503 µg/l). Similarly, in vivo, System 2 demonstrated signal-to-background ratio (SBR) of 2.6 ± 0.63 before dura opening, 5.0 ± 1.7 after dura opening, and 6.1 ± 1.9 after tumor exposure. In contrast, System 1 could not easily detect ICG fluorescence prior to dura opening with SBR of 1.2 ± 0.15. After the dura was reflected, SBR increased to 1.4 ± 0.19 and upon exposure of the tumor SBR increased to 1.8 ± 0.26. CONCLUSION: Dedicated NIR imaging platforms can outperform conventional microscopes in intraoperative NIR detection. Future microscopes with improved NIR detection capabilities could enhance the use of NIR fluorescence to detect neoplasm and improve patient outcome.

The second window ICG technique demonstrates a broad plateau period for near infrared fluorescence tumor contrast in glioblastoma.

INTRODUCTION: Fluorescence-guided surgery has emerged as a powerful tool to detect, localize and resect tumors in the operative setting. Our laboratory has pioneered a novel way to administer an FDA-approved near-infrared (NIR) contrast agent to help surgeons with this task. This technique, coined Second Window ICG, exploits the natural permeability of tumor vasculature and its poor clearance to deliver high doses of indocyanine green (ICG) to tumors. This technique differs substantially from established ICG video angiography techniques that visualize ICG within minutes of injection. We hypothesized that Second Window ICG can provide NIR optical contrast with good signal characteristics in intracranial brain tumors over a longer period of time than previously appreciated with ICG video angiography alone. We tested this hypothesis in an intracranial mouse glioblastoma model, and corroborated this in a human clinical trial. METHODS: Intracranial tumors were established in 20 mice using the U251-Luc-GFP cell line. Successful grafts were confirmed with bioluminescence. Intravenous tail vein injections of 5.0 mg/kg (high dose) or 2.5 mg/kg (low dose) ICG were performed. The Perkin Elmer IVIS Spectrum (closed field) was used to visualize NIR fluorescence signal at seven delayed time points following ICG injection. NIR signals were quantified using LivingImage software. Based on the success of our results, human subjects were recruited to a clinical trial and intravenously injected with high dose 5.0 mg/kg. Imaging was performed with the VisionSense Iridium (open field) during surgery one day after ICG injection. RESULTS: In the murine model, the NIR signal-to-background ratio (SBR) in gliomas peaks at one hour after infusion, then plateaus and remains strong and stable for at least 48 hours. Higher dose 5.0 mg/kg improves NIR signal as compared to lower dose at 2.5 mg/kg (SBR = 3.5 vs. 2.8; P = 0.0624). Although early (≤ 6 hrs) visualization of the Second Window ICG accumulation in gliomas is stronger than late (≥24 hrs) visualization (SBR = 3.94 vs. 2.32; p<0.05) there appears to be a long plateau period of stable ICG NIR signal accumulation within tumors in the murine model. We call this long plateau period the "Second Window" of ICG. In glioblastoma patients, the delayed visualization of intratumoral NIR signal was strong (SBR 7.50 ± 0.74), without any significant difference within the 19 to 30 hour visualization window (R2 = 0.019). CONCLUSION: The Second Window ICG technique allows neurosurgeons to deliver NIR optical contrast agent to human glioblastoma patients, thus providing real-time tumor identification in the operating room. This nonspecific tumor accumulation of ICG within the tumor provides strong signal to background contrast, and is not significantly time dependent between 6 hours to 48 hours, providing a broad plateau for stable visualization. This finding suggests that optimal imaging of the "Second Window of ICG" may be within this plateau period, thus providing signal uniformity across subjects.

Intraoperative Near-Infrared Optical Contrast Can Localize Brain Metastases.

INTRODUCTION: Approximately 100,000 brain metastases are diagnosed annually in the United States. Our laboratory has pioneered a novel technique, second window indocyanine green (SWIG), which allows for real-time intraoperative visualization of brain metastasis through normal brain parenchyma and intact dura. METHODS: Thirteen patients with intraparenchymal brain metastases were administered indocyanine green (ICG) at 5 mg/kg the day before surgery. A near-infrared (NIR)- capable camera was used intraoperatively to identify the tumor and to inspect surgical margins. Neuropathology was used to assess the accuracy and precision of the fluorescent dye for identifying tumor. RESULTS: ICG was infused at 24.7 ± 3.45 hours before visualization. All 13 metastases fluoresced with an average signal-to-background ratio (SBR) of 6.62. The SBR with the dura intact was 67.2% of the mean SBR once the dura was opened. The NIR signal could be visualized through normal brain parenchyma up to 7 mm. For the 39 total specimens, the mean SBR for tumor specimens (n = 28) was 6.9, whereas the SBR for nontumor specimens (n = 11) was 3.7. The sensitivity, specificity, positive predictive value, and negative predictive value of NIR imaging for tumor was 96.4%, 27.3%, 77.1%, and 75.0%. DISCUSSION: SWIG relies on the passive accumulation of dye in abnormal tumor tissue via the enhanced permeability and retention effect. It provides strong NIR optical contrast, which can be used to localize tumors before dural opening. The use of SWIG for margin assessment remains limited by its lack of specificity (high false-positive rate); however, ongoing improvements in imaging parameters show great potential to reduce false-positive results.

Near-infrared Intraoperative Molecular Imaging Can Identify Metastatic Lymph Nodes in Prostate Cancer.

OBJECTIVE: To propose a novel method to perform indocyanine green (ICG) based near-infrared (NIR) fluorescence imaging during pelvic lymph node dissection (PLND) for prostate cancer patients with lymph node metastasis (LNM). MATERIALS AND METHODS: A prostate cancer cell line PC3 was used to establish xenograft model in NOD/SCID mice. After tumor growth, the mice were injected with ICG through the tail vein. Xenografts and surrounding tissues were imaged with NIR camera 24 hours after intravenous ICG, and tumor-to-background ratios were calculated. We then performed a pilot human study to evaluate the role of NIR imaging in robotic PLND after systemic ICG in 4 patients with prostate cancer and preoperative lymphadenopathy. RESULTS: ICG localized to PC3 xenografts in the mice and all xenografts were highly fluorescent compared with surrounding tissues, with a median tumor-to-background ratio of 2.85 (interquartile range = 2.64-3.90). In the human study, intraoperative in vivo NIR imaging identified 3 of the 4 preoperative lymphadenopathies as fluorescence-positive, and back table ex vivo NIR imaging identified all 4 lymphadenopathies as fluorescence-positive. All the lymphadenopathies were found to be LNMs by pathologic examination. Two of the four cases had additional LNMs, all of which were fluorescence-positive with intraoperative in vivo NIR imaging. CONCLUSION: Intravenously administered ICG accumulates in prostate cancers in both a murine model and human patients. NIR fluorescence based on intravenous ICG may serve as a useful tool to facilitate the identification of positive nodes during PLND in patients with higher risk of LNMs.

Near-Infrared Intraoperative Molecular Imaging Can Locate Metastases to the Lung.

BACKGROUND: Pulmonary metastasectomy is widely accepted for many tumor types because it may prolong survival and potentially cure some patients. However, intraoperative localization of pulmonary metastases can be technically challenging. We propose that intraoperative near-infrared (NIR) molecular imaging can be used as an adjunct during disease localization. METHODS: We inoculated 50 C57BL/6 mice with Lewis lung carcinoma (LLC) flank tumors. After flank tumor growth, mice were injected through the tail vein with indocyanine green (ICG) before operation, and intraoperative imaging was used to detect pulmonary metastases. On the basis of these experiments, we enrolled 8 patients undergoing pulmonary metastasectomy into a pilot and feasibility clinical trial. Each patient received intravenous ICG 1 day before operation, followed by wedge or segmental resection. Samples were imaged on the back table with an NIR camera to confirm disease presence and margins. All murine and human tumors and margins were confirmed by pathologic examination. RESULTS: Mice had an average of 4 ± 2 metastatic tumors on both lungs, with an average size of 5.1 mm (interquartile range [IQR] 2.2 mm to 7.6 mm). Overall, 200 of 211 (95%) metastatic deposits were markedly fluorescent, with a mean tumor-to-background ratio (TBR) of 3.4 (IQR 3.1 to 4.1). The remaining tumors had a TBR below 1.5. In the human study, intraoperative NIR imaging identified six of the eight preoperatively localized lesions. Intraoperative back table NIR imaging identified all metastatic lesions, which were confirmed by pathologic examination. The average tumor size was 1.75 ± 1.4 cm, and the mean ex vivo TBR was 3.3 (IQR 3.1 to 3.7). Pathologic examination demonstrated melanoma (n = 4), osteogenic sarcoma (n = 2), renal cell carcinoma (n = 2), chondrosarcoma (n = 1), leiomyosarcoma (n = 1), and colorectal carcinoma (n = 1). CONCLUSIONS: Systemic ICG identifies subcentimeter tumor metastases to the lung in murine models, and this work provides proof of principle in humans. Future research is focused on improving depth of penetration into the lung parenchyma.

Intraoperative Near-Infrared Optical Imaging Can Localize Gadolinium-Enhancing Gliomas During Surgery.

BACKGROUND: Although real-time localization of gliomas has improved with intraoperative image guidance systems, these tools are limited by brain shift, surgical cavity deformation, and expense. OBJECTIVE: To propose a novel method to perform near-infrared (NIR) imaging during glioma resections based on preclinical and clinical investigations, in order to localize tumors and to potentially identify residual disease. METHODS: Fifteen patients were identified and administered a Food and Drug Administration-approved, NIR contrast agent (Second Window indocyanine green [ICG], 5 mg/kg) before surgical resection. An NIR camera was utilized to localize the tumor before resection and to visualize surgical margins following resection. Neuropathology and magnetic resonance imaging data were used to assess the accuracy and precision of NIR fluorescence in identifying tumor tissue. RESULTS: NIR visualization of 15 gliomas (10 glioblastoma multiforme, 1 anaplastic astrocytoma, 2 low-grade astrocytoma, 1 juvenile pilocytic astrocytoma, and 1 ganglioglioma) was performed 22.7 hours (mean) after intravenous injection of ICG. During surgery, 12 of 15 tumors were visualized with the NIR camera. The mean signal-to-background ratio was 9.5 ± 0.8 and fluorescence was noted through the dura to a maximum parenchymal depth of 13 mm. The best predictor of positive fluorescence was enhancement on T1-weighted imaging; this correlated with signal-to-background ratio (P = .03). Nonenhancing tumors did not demonstrate NIR fluorescence. Using pathology as the gold standard, the technique demonstrated a sensitivity of 98% and specificity of 45% to identify tumor in gadolinium-enhancing specimens (n = 71). CONCLUSION: With the use of Second Window ICG, gadolinium-enhancing tumors can be localized through brain parenchyma intraoperatively. Its utility for margin detection is promising but limited by lower specificity. ABBREVIATIONS: 5-ALA, 5-aminolevulinic acidEPR, enhanced permeability and retentionFDA, Food and Drug AdministrationGBM, glioblastomaICG, indocyanine greenNIR, near-infraredNPV, negative predictive valuePPV, positive predictive valueROC, receiver operating characteristicROI, region of interestSBR, signal-to-background ratioWHO, World Health Organization.