Prospective validation of tumor folate receptor expression density with the association of pafolacianine fluorescence during intraoperative molecular imaging-guided lung cancer resections.

PURPOSE: Pafolacianine, a folate receptor alpha-targeted NIR tracer, has demonstrated clear efficacy in intraoperative molecular imaging-guided (IMI) lung cancer surgery. However, the selection of patients who would benefit from IMI remains challenging given the variability of fluorescence with patient-associated and histopathologic factors. Our goal in this study was to prospectively evaluate whether preoperative FRα/FRß staining can predict pafolacianine-based fluorescence during real-time lung cancer resections. METHODS: This was a prospective study conducted between 2018 and 2022 that reviewed core biopsy and intraoperative data from patients with suspected lung cancer. A total of 196 patients were deemed eligible, of whom core biopsies were taken from 38 patients and assessed for FRα and FRß expression by immunohistochemistry (IHC). All patients underwent infusion of pafolacianine 24 h prior to surgery. Intraoperative fluorescence images were captured with the VisionSense bandpass filter-enabled camera. All histopathologic assessments were performed by a board-certified thoracic pathologist. RESULTS: Of the 38 patients, 5 (13.1%) were found to have benign lesions (necrotizing granulomatous inflammation, lymphoid aggregates) and 1 had metastatic non-lung nodule. Thirty (81.5%) had malignant lesions, with the vast majority (23, 77.4%) being lung adenocarcinoma (7 (22.5%) SCC). None of the benign tumors (0/5, 0%) exhibited in vivo fluorescence (mean TBR of 1.72), while 95% of the malignant tumors fluoresced (mean TBR of 3.11 ± 0.31) compared to squamous cell carcinoma (1.89 ± 0.29) of the lung and sarcomatous lung metastasis (2.32 ± 0.09) (p < 0.01). The TBR was significantly higher in the malignant tumors (p = 0.009). The median FRα and FRß staining intensities were both 1.5 for benign tumors, while the FRα and FRß staining intensities were 3 and 2 for malignant tumors, respectively. Increased FRα expression was significantly associated with the presence of fluorescence (p = 0.01), CONCLUSION: This prospective study sought to determine whether preoperative FRα and FRß expression on core biopsy IHC correlates with intraoperative fluorescence during pafolacianine-guided surgery. These results, although of small sample size, including limited non-adenocarcinoma cohort, suggest that performing FRα IHC on preoperative core biopsies of adenocarcinomas as compared to squamous cell carcinomas could provide low-cost, clinically useful information for optimal patient selection which should be further explored in advanced clinical trials.

Preclinical Evaluation of an Activity-Based Probe for Intraoperative Imaging of Esophageal Cancer.

Background: Early detection and complete resection are important prognostic factors for esophageal cancer (EC). Intraoperative molecular imaging (IMI) using tumor-targeted tracers is effective in many cancer types. However, there are no EC-specific IMI tracers. We sought to test a cathepsin activity-based tracer (VGT-309) for EC resection. Methods: Murine (AKR, HNM007) and human (OE19) EC cell lines were screened for cathepsin expression by western blotting. In vitro binding affinity of VGT-309 was evaluated by fluorescence microscopy. Flank tumor models were developed by injecting EC cells into the flanks of BALB/c or athymic nude mice. Mice pretreated with a cathepsin inhibitor (JPM-OEt) were used to confirm on target binding. Animals were injected with 2 mg/kg VGT-309, underwent IMI, and were sacrificed 24 hours after injection. Results: Cathepsins B, L, S, and X were expressed by EC cell lines, and all cell lines were labeled in vitro with VGT-309. Fluorescent signal was eliminated when cells were pretreated with JPM-OEt. On biodistribution analysis, VGT-309 accumulated in the liver, kidneys, and spleen without other organ involvement. VGT-309 selectively accumulated in flank allografts and xenografts, with mean signal-to-background ratio of 5.21 (IQR: 4.18-6.73) for flank allografts and 4.34 (IQR: 3.75-5.02) for flank xenografts. Fluorescence microscopy and histopathological analysis confirmed the selective accumulation of the tracer in tumors compared to background normal tissues. Conclusions: VGT-309 is an effective tracer for IMI of esophageal cancer. There is potential for clinical translation both as an adjunct to endoscopic detection and for complete removal of disease during esophagectomy.

Comparative Experience of Short-wavelength Versus Long-wavelength Fluorophores for Intraoperative Molecular Imaging of Lung Cancer.

BACKGROUND: Intraoperative molecular imaging (IMI) using tumor-targeted optical contrast agents can improve cancer resections. The optimal wavelength of the IMI tracer fluorophore has never been studied in humans and has major implications for the field. To address this question, we investigated 2 spectroscopically distinct fluorophores conjugated to the same targeting ligand. METHODS: Between December 2011 and November 2021, patients with primary lung cancer were preoperatively infused with 1 of 2 folate receptor-targeted contrast tracers: a short-wavelength folate-fluorescein (EC17; λ em =520 nm) or a long-wavelength folate-S0456 (pafolacianine; λ em =793 nm). During resection, IMI was utilized to identify pulmonary nodules and confirm margins. Demographic data, lesion diagnoses, and fluorescence data were collected prospectively. RESULTS: Two hundred eighty-two patients underwent resection of primary lung cancers with either folate-fluorescein (n=71, 25.2%) or pafolacianine (n=211, 74.8%). Most tumors (n=208, 73.8%) were invasive adenocarcinomas. We identified 2 clinical applications of IMI: localization of nonpalpable lesions (n=39 lesions, 13.8%) and detection of positive margins (n=11, 3.9%). In each application, the long-wavelength tracer was superior to the short-wavelength tracer regarding depth of penetration, signal-to-background ratio, and frequency of event. Pafolacianine was more effective for detecting subpleural lesions (mean signal-to-background ratio=2.71 vs 1.73 for folate-fluorescein, P <0.0001). Limit of signal detection was 1.8 cm from the pleural surface for pafolacianine and 0.3 cm for folate-fluorescein. CONCLUSIONS: Long-wavelength near-infrared fluorophores are superior to short-wavelength IMI fluorophores in human tissues. Therefore, future efforts in all human cancers should likely focus on long-wavelength agents.

Presence of non-Newtonian fluid in invasive pulmonary mucinous adenocarcinomas impacts fluorescence during intraoperative molecular imaging of lung cancer.

BACKGROUND: Intraoperative molecular imaging (IMI) with folate-targeted NIR tracers has been shown to improve lesion localization in more than 80% of lung adenocarcinomas. However, mucinous adenocarcinomas (MAs) and invasive mucinous adenocarcinomas (IMAs) of the lung, which are variants of adenocarcinoma, appear to have decreased fluorescence despite appropriate folate receptor expression on the tumor surface. We hypothesized that the etiology may be related to light excitation and emission through non-Newtonian fluid (mucin) produced by goblet and columnar cancer cells. METHODS: Intraoperative data for 311 subjects were retrospectively reviewed from a prospectively collected 6-year database. For standardization, all patients underwent infusion of the same targeted molecular optical contrast agent (pafolacianine, folate receptor-targeted NIR fluorochrome) for lung cancer resections. Then, the ratio of the mean fluorescence intensity of the tumors and background tissues (TBR) was calculated. Tumors were examined for mucin, FRa, FRb, and immunofluorescent tracer uptake by a board-certified pathologist. The optical properties of mucin analyzed by imaging software were used to create in vitro gel models to explore the effects on NIR tracer fluorescence intensity. RESULTS: A large proportion (192, 62%) of the patients were female, with an average of 62.8 years and a 34-year mean pack smoking history. There were no severe (Clavien-Dindo > III) complications related to pafolacianine infusion. A total of 195 lesions in the study were adenocarcinomas, of which 19 (6.1%) were of the mucinous subtype. A total of 14/19 of the patients had a smoking history, and more than 74% of the IMA lesions were in the lower lobes. IMA lesions had a lower in situ TBR than nonmucinous adenocarcinomas (2.64 SD 0.23) vs (3.45 SD 0.11), respectively (p < 0.05). Only 9/19 (47%) were localized in situ. Tumor bisection and removal of mucin from IMAs significantly increased pafolacianine fluorescence, with resultant TBR not being significantly different from the control group (4.67 vs 4.89) (p = 0.19). Of the 16 lesions that underwent FR expression analysis, 15/16 had FR presence on cancer cells or tumor-associated macrophages in the tumor microenvironment. There was no statistically significant difference in fluorescence intensity during immunofluorescence analysis (4.99 vs 5.08) (p = 0.16). Physical removal of mucin from IMAs improved the TBR from 3.11 to 4.67 (p < 0.05). In vitro analysis of the impact of synthetic non-Newtonian fluid (agarose 0.5%) on NIR tracer fluorescence showed a decrease in MFI by a factor of 0.25 regardless of the concentration for each 5 mm thickness of mucin. CONCLUSION: The mucinous subtype of lung adenocarcinomas presents a unique challenge in pafolacianine-targeted IMI-guided resections. The presence of non-Newtonian fluids presents a physical barrier that dampens the excitation of the tracer and fluorescence emission detected by the camera. Knowledge of this phenomenon can allow the surgeon to critically analyze lesion fluorescence parameters during IMI-guided lung cancer resections.

Targeted detection of cancer cells during biopsy allows real-time diagnosis of pulmonary nodules.

BACKGROUND: The diagnostic yield of biopsies of solitary pulmonary nodules (SPNs) is low, particularly in sub-solid lesions. We developed a method (NIR-nCLE) to achieve cellular level cancer detection during biopsy by integrating (i) near-infrared (NIR) imaging using a cancer-targeted tracer (pafolacianine), and (ii) a flexible NIR confocal laser endomicroscopy (CLE) system that can fit within a biopsy needle. Our goal was to assess the diagnostic accuracy of NIR-nCLE ex vivo in SPNs. METHODS: Twenty patients with SPNs were preoperatively infused with pafolacianine. Following resection, specimens were inspected to identify the lesion of interest. NIR-nCLE imaging followed by tissue biopsy was performed within the lesion and in normal lung tissue. All imaging sequences (n = 115) were scored by 5 blinded raters on the presence of fluorescent cancer cells and compared to diagnoses by a thoracic pathologist. RESULTS: Most lesions (n = 15, 71%) were adenocarcinoma-spectrum malignancies, including 7 ground glass opacities (33%). Mean fluorescence intensity (MFI) by NIR-nCLE for tumor biopsy was 20.6 arbitrary units (A.U.) and mean MFI for normal lung was 6.4 A.U. (p < 0.001). Receiver operating characteristic analysis yielded a high area under the curve for MFI (AUC = 0.951). Blinded raters scored the NIR-nCLE sequences on the presence of fluorescent cancer cells with sensitivity and specificity of 98% and 97%, respectively. Overall diagnostic accuracy was 97%. The inter-observer agreement of the five raters was excellent (κ = 0.95). CONCLUSIONS: NIR-nCLE allows sensitive and specific detection of cancer cells in SPNs. This technology has far-reaching implications for diagnostic needle biopsies and intraprocedural decision-making.

Patterns of Metastasis in Merkel Cell Carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy with a propensity for regional and distant spread. Because of the relative infrequency of this disease, the patterns of metastasis in MCC are understudied. METHODS: Patients with American Joint Committee on Cancer (8th edition) stage I-IV MCC treated at our institution were identified (1/1/2008-2/28/2018). The first site of metastasis was classified as regional [regional lymph node (LN) basin, in-transit] or distant. Distant metastasis-free (DMFS) and MCC-specific (MSS) survival were estimated. RESULTS: Of 133 patients, 64 (48%) had stage I, 13 (10%) stage II, 48 (36%) stage III, and 8 (6%) stage IV disease at presentation. The median follow-up time in patients who remained alive was 36 (interquartile range 20-66) months. Regional or distant metastases developed in 78 (59%) patients. The first site was regional in 87%, including 73% with isolated LN involvement, and distant in 13%. Thirty-seven (28%) patients eventually developed distant disease, which most commonly involved the abdominal viscera (51%) and distant LNs (46%) first. The lung (0%) and brain (3%) were rarely the first distant sites. Stage III MCC at presentation was significantly associated with worse DMFS (hazard ratio 4.87, P = 0.001) and stage IV disease with worse MSS (hazard ratio 6.30, P = 0.002). CONCLUSIONS: Regional LN metastasis is the most common first metastatic event in MCC, confirming the importance of nodal evaluation. Distant disease spread appears to have a predilection for certain sites. Understanding these patterns could help to guide surveillance strategies.

Practice Patterns and Prognostic Value of Sentinel Lymph Node Biopsy for Thick Melanoma: A National Cancer Database Study.

BACKGROUND: Sentinel lymph node biopsy (SLNB) has been somewhat controversial for patients with a diagnosis of thick (> 4 mm) melanoma. This study aimed to characterize the national practice pattern in performing SLNB for this patient population and to determine the predictors and prognostic value of nodal positivity using population-level data. METHODS: Patients with a diagnosis of clinically node-negative, thick melanoma (2010-2015) were identified using the National Cancer Database. Factors associated with performing regional nodal evaluation were characterized. Predictors of nodal positivity were determined using multivariable logistic regression. Overall survival (OS) was estimated using standard statistical methods. RESULTS: Of 9847 study patients, 7513 (76.3%) underwent SLNB. The patients who underwent nodal evaluation were younger (median age, 66 vs 81 years; P < 0.001), less likely to have comorbid conditions (19.6% vs 26.0%; P < 0.001), more often privately insured (40.4% vs 16.4%; P < 0.001), and more frequently treated at an academic center (49.5% vs 43.9%; P < 0.001). Among those who underwent nodal evaluation, 25.5% had metastatic nodes. Multivariable regression identified age, Charlson-Deyo score, primary location, ulceration, mitoses, vertical growth phase, and lymphovascular invasion as independent predictors of nodal positivity, but with only moderate predictive accuracy (optimism-adjusted area under the curve, 0.684). Furthermore, compared with node negativity, node positivity was significantly associated with decreased OS (hazard ratio, 2.05; P < 0.001). CONCLUSION: Although nodal status provides important prognostic information, at a national level, nearly one fourth of patients with clinically node-negative, thick melanoma do not undergo SLNB. Appropriate pathologic staging would allow these high-risk patients to be candidates for effective adjuvant therapy.

Molecular Imaging in Precision-Cut Non-Small Cell Lung Cancer Slices.

BACKGROUND: Small animal models remain invaluable for the preclinical study of emerging molecular imaging agents. However, the data obtained in this setting are generated in genetically homogenous animals that do not mimic human pathophysiology. The purpose of this study was to prospectively validate precision-cut lung slices (PCLSs) obtained from patients with lung cancer as a translational tool for the development of targeted fluorophores. METHODS: The lung tissue was gently inflated with 2% Low-Melt Agarose (Fisher, 16520050) to avoid lung damage and minimize inflation pressure. The slices were then loaded into specialized cylindrical cartridges and inserted into a compressotome, and slices 150 to 350 µm thick were cut. Samples were incubated with fluorophore conjugates for ex vivo validation and immunohistochemical staining for receptor expression. RESULTS: A total of 184 unique 3-dimensional, architecturally preserved normal lung and non-small cell lung cancer samples were obtained between 2020 and 2022. The median nodule size was 1.1 ± 0.21 cm for benign lesions and 2.1 ± 0.19 cm for malignant nodules. A total of 101 of 135 (74.8%) malignant lesions were adenocarcinoma spectrum lung cancers. The median viability was 9.78 ± 1.86 days, and 1 µM of FAPL-S0456 (high-affinity fibroblast activation protein [FAP] targeting ligand linked to the near-infrared fluorophore S0456, On Target Laboratories)-targeted near-infrared fluorochrome localization demonstrated correlative labeling of FAP-positive tumor areas with a correlation coefficient of +0.94 (P < .01). There was no FAP fluorochrome uptake in normal lungs (r = -1; P < .001). CONCLUSIONS: PCLSs comprise a novel human tissue-based translational model that can be used to validate the efficacy of molecular imaging fluorochromes. PCLSs preserve the tumor microenvironment and parenchymal architecture that closely resemble the interactions of the immune and stromal components in humans.

A Phase 2 Multicenter Clinical Trial of Intraoperative Molecular Imaging of Lung Cancer with a pH-Activatable Nanoprobe.

PURPOSE: Intraoperative molecular imaging (IMI) uses tumor-targeted optical contrast agents to improve identification and clearance of cancer. Recently, a probe has been developed that only fluoresces when activated in an acidic pH, which is common to many malignancies. We report the first multicenter Phase 2 trial of a pH-activatable nanoprobe (pegsitacianine, ONM-100) for IMI of lung cancer. METHODS: Patients with suspected or biopsy-confirmed lung cancer scheduled for sublobar resection were administered a single intravenous infusion of pegsitacianine (1 mg/kg) one to three days prior to surgery. Intraoperatively, the patients underwent a white light thoracoscopic evaluation, and then were imaged with an NIR thoracoscope to detect tumor fluorescence. The primary study endpoint was the proportion of patients with a clinically significant event (CSE) which was defined as an intraoperative discovery during IMI that led to a change in the surgical procedure. Possible CSEs included (i) localizing the index lung nodule that could not be located by white light, (ii) identifying a synchronous malignant lesion, or (iii) recognizing a close surgical margin (< = 10 mm). Secondary endpoints were sensitivity, specificity, NPV, and PPV of pegsitacianine in detecting tumor-containing tissue. The safety evaluation was based on adverse event reporting, clinical laboratory parameters, and physical examinations. RESULTS: Twenty patients were confirmed as eligible and administered pegsitacianine. Most of the patients were female (n = 12 [60%]), middle-aged (mean age 63.4 years), and former smokers (n = 13 [65%], 28.6 mean pack years). Mean lesion size was 1.9 cm, and most lesions (n = 17 [85%]) were malignant. The most common histologic subtype was adenocarcinoma (n = 9). By utilizing IMI with pegsitacianine, one patient had a CSE in the detection of a close margin and another had localization of a tumor not detectable by traditional surgical means. Six of 19 (31.6%) malignant lesions fluoresced with mean tumor-to-background ratio (TBR) of 3.00, as compared to TBR of 1.20 for benign lesions (n = 3). Sensitivity and specificity of pegsitacianine-based IMI for detecting malignant tissue was 31.6% and 33.3%, respectively. Positive predictive value (PPV) and negative predictive value (NPV) of pegsitacianine-based IMI was 75% and 7.1%, respectively. Pegsitacianine-based imaging was not effective in differentiating benign and malignant lymph nodes. From a safety perspective, no drug-related serious adverse events occurred. Four patients experienced mild pegsitacianine-related infusion reactions which required discontinuing the study drug with complete resolution of symptoms. CONCLUSIONS: Pegsitacianine-based IMI, though well tolerated from a safety perspective, does not consistently label lung tumors during resection and does not provide significant clinical benefit over existing standards of surgical care. The biology of lung tumors may not be as acidic as other solid tumors in the body thereby not activating the probe as predicted.

Phase 2 Clinical Trial of VGT-309 for Intraoperative Molecular Imaging During Pulmonary Resection.

BACKGROUND: Advances in intraoperative molecular imaging (IMI) may improve surgical outcomes when resecting tumors in the lung. A single-center trial was conducted using VGT-309, a cathepsin-targeted near-infrared imaging agent that causes lung nodules to fluoresce during surgical resection. The end point of this phase 2 study was to evaluate the frequency that IMI with VGT-309 resulted in a clinically significant event (CSE): localization of pulmonary nodules, discovery of unsuspected additional cancers, or identification of positive margins. METHODS: Patients undergoing surgical resection for known or suspected cancer in the lung received VGT-309 (0.32 mg/kg) preoperatively. During the surgical procedure, localization and resection of the nodules were performed using standard surgical techniques. Near-infrared imaging was then used to localize nodules, seek occult lesions, and assess resection margins. Efficacy was measured by the frequency of CSEs. RESULTS: Of the 40 patients who underwent pulmonary resection with VGT-309, 17 (42.5%) had at least 1 CSE. Near-infrared imaging identified lesions not found by standard surgical methods in 16 patients, additional cancers not found by preoperative imaging in 1 patient, and margins within 5 mm of the closest staple line in 2 patients. VGT-309 performance was tested across a broad range of tumor types and commercial near-infrared imaging systems. VGT-309 appeared safe, well-tolerated, with no infusion reactions, and no drug-related serious adverse events. CONCLUSIONS: This phase 2 study demonstrated the utility of IMI with VGT-309 in localizing pulmonary nodules, recognizing synchronous lesions, and identifying positive margins. A multi-institutional study will further evaluate the efficacy of VGT-309.

Preoperative predictors of successful tumour localization by intraoperative molecular imaging with pafolacianine in lung cancer to create predictive nomogram.

OBJECTIVES: Intraoperative molecular imaging (IMI) uses cancer-targeted fluorescent probe to locate nodules. Pafolacianine is a Food and Drug Administration-approved fluorescent probe for lung cancer. However, it has a 8-12% false negative rate for localization. Our goal is to define preoperative predictors of tumour localization by IMI. METHODS: We performed a retrospective review of patients who underwent IMI using pafolacianine for lung lesions from June 2015 to August 2019. Candidate predictors including sex, age, body mass index, smoking history, tumour size, distance of tumour from surface, use of neoadjuvant therapy and positron emission tomography avidity were included. The outcome was fluorescence in vivo and comprehensively included those who were true or false positives negatives. Multiple imputation was used to handle the missing data. The final model was evaluated using the area under the receiver operating characteristic curve. RESULTS: Three hundred nine patients were included in our study. The mean age was 64 (standard deviation 13) and 68% had a smoking history. The mean distance of the tumours from the pleural surface was 0.4 cm (standard deviation 0.6). Smoking in pack-years and distance from pleura had an odds ratio of 0.99 [95% confidence interval: 0.98-0.99; P = 0.03] and 0.46 [95% confidence interval: 0.27-0.78; P = 0.004], respectively. The final model had an area under the receiver operating characteristic curve of 0.68 and was used to create a nomogram that gives a probability of fluorescence in vivo. CONCLUSIONS: Primary tumours that are deeper from the pleural surface, especially in patients with a higher pack-years, are associated with a decreased likelihood of intraoperative localization. We identified a nomogram to predict the likelihood of tumour localization with IMI with pafolacianine.

Evaluation of OTL38-Generated Tumor-to-Background Ratio in Intraoperative Molecular Imaging-Guided Lung Cancer Resections.

INTRODUCTION: Cancer surgery has multiple challenges including localizing small lesions, ensuring negative margins, and identifying synchronous cancers. One of the tools proposed to address these issues is intraoperative molecular imaging (IMI). An important consideration in IMI is the quantification of the tumor fluorescence during the procedure and using that data to add clinical value. Currently, the most commonly cited measure of quantification is the tumor-to-background ratio (TBR). Our goal was to evaluate the clinical value of TBR measured with OTL38 NIR tracer during a lung cancer resection. METHODS: Intraoperative data was retrospectively reviewed from a prospectively collected 5-year database. Between 2015 and 2020, 279 patients were included in the study. For standardization, all patients underwent infusion of the same targeted molecular optical contrast agent (OTL38) for lung cancer resections; then, the mean fluorescence intensity of the tumors and background tissues were calculated. To evaluate the clinical efficacy of the TBR calculation, the results were correlated with patient, biologic, tumor, and technological factors. RESULTS: For pulmonary surgery, patient factors such as gender, age, smoking history, and time from infusion of OTL38 to surgery did not have any statistical significance in predicting the TBR during surgery. In addition, TBR measurements did not correlate with location of the tumor in the lung (p = 0.123). There was no statistical correlation of preoperative positron emission tomography measurements (standardized uptake value) with intraoperative TBR. However, there was statistically significant negative correlation of in situ TBR measurement and the distance of the lesion from the surface of the organ (p < 0.001). Adenocarcinoma spectrum lesions overall had statistically significant correlation with in situ fluorescence compared to other NSCLC malignancies (p < 0.01) but TBR measurements could not identify histopathologic subtype on univariate analysis (p = 0.089). There was a tendency for in situ fluorescence for moderately and well-differentiated adenocarcinoma spectrum lesions, but this was not statistically significant. When comparing the in situ TBR of benign to malignant nodules in the lung, there was no statistically significant association (p = 0.145). In subset analysis, adenocarcinoma spectrum lesions tend to fluoresce at brighter with OTL38 compared to other histologic subtypes. CONCLUSION: In our various iterations, the results of our retrospective analysis did not show that TBR measurements during OTL38-guided surgery provide clinically useful information about the nature of the nodule or cancer. The true value of IMI is in the ability for the surgeon to use the fluorescence to guide the surgeon to the tumor and margins, but that sophisticated quantification of the amount of fluorescence may not have clinical utility.

Effects of Light-absorbing Carbons in Intraoperative Molecular Imaging-Guided Lung Cancer Resections.

BACKGROUND: One of the novel advancements to enhance the visual aspects of lung cancer identification is intraoperative molecular imaging (IMI), which can reliably detect tumors that would otherwise be missed by standard techniques such as tactile and visual feedback, particularly for sub-centimeter or ground-glass nodules. However, there remains a subset of patients who do not benefit from IMI due to excessive background fluorescence secondary to parenchymal light-absorbing carbon deposition. Our goal was to identify the effects of these carbonaceous materials on the quality of IMI-guided lung cancer resections. STUDY DESIGN AND METHODS: Between July 2014 and May 2021, a total of 311 patients were included in the study. Patients underwent infusion of the study drug OTL38 or ICG up to 24 h prior to VATS for lung cancer. Several factors such as age, tumor subtype, PET SUV, smoking, demographics, chronic lung conditions, patient domicile, and anthracosis were analyzed with respect to lung fluorescence during IMI. P values < 0.05 were considered statistically significant. RESULTS: Variables such as age, sex, and race had no statistical correlation to IMI success. However, smoking status and pack year had a statistically significant correlation with background parenchymal fluorescence and lung inflammation (p < 0.05). MFI of background (lung parenchyma) correlated with smoking history (p < 0.05) which led to decreased tumor-to-background ratio (TBR) measurements for all patients with proven malignancy (p < 0.05). Patients with chronic lung disease appear to have increased background parenchymal fluorescence regardless of smoking history (287 vs. 154, p < 0.01). City dwellers compared to other groups appear to be exposed to higher pollutant load and have higher rates of anthracosis, but living location's impact on fluorescence quantification appears to be not statistically significant. CONCLUSION: Smokers with greater than 10 PPY and those with chronic lung disease appear to have decreased lesion-to-background discrimination, significant anthracosis, and reduced IMI efficacy secondary to light-absorbing carbon deposition.

Glycoprotein Receptor CEACAM5-Targeted Intraoperative Molecular Imaging Tracer in Non-Small Cell Lung Cancer.

BACKGROUND: Intraoperative molecular imaging has emerged as a potential tool in addressing challenges faced during lung cancer surgery by localizing small lesions, ensuring negative margins, and identifying synchronous cancers. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) glycoprotein has emerged as a potential target in fluorescent labeling of non-small cell lung cancer given the high antigen density in tumor cells and absence of expression in normal parenchyma. The goal of our study was to determine whether anti-CEACAM5 targeted near-infrared fluorochrome could be a suitable target in non-small cell lung cancer. METHODS: The CEACAM5 expression was evaluated in AB-12 (known negative control), HT29 (known positive control), and H460 (non-small cell lung cancer) cell lines by polymerase chain reaction. SGM-101, a CEACAM5 antibody, coupled with a BM-104 near-infrared fluorescent tracer was evaluated with dose escalation, in vitro cellular localization, and immunofluorescence microscopy. Subsequently, in vivo validation was performed in 52 athymic nude xenografts. RESULTS: Polymerase chain reaction analysis demonstrated 3000x relative expression of CEACAM5 in HT-29 cells compared with AB-12. The H460 cells showed 1000x relative expression compared with AB12 (P < .05). Both HT29 and H460 cells showed tracer internalization with signal to background ratio of 4.5 (SD 0.34) whereas there was minimal uptake by AB12 cells with signal to background ratio 1.1 (SD 0.1; P < .05). There was linear fluorescence increase with increasing tracer dosing in receptor expressing cell lines. In preclinical models, HT-29 and H460 cells lines produced near-infrared fluorescence with average tumor to background ratio of 3.89 (SD 0.25) irrespective of tumor size compared with no fluorescence by AB12 tumors (P < .05). The CEACAM5 expressing tumors had excellent dye uptake compared with AB12 tumors. CONCLUSIONS: CEACAM5 serves as a possible receptor for targeted intraoperative molecular imaging resections in lung cancer. This study sets a path for evaluation of CEACAM5 targets in future clinical trials.

Three-Dimensional Near-Infrared Specimen Mapping Can Identify the Distance from the Tumor to the Surgical Margin During Resection of Pulmonary Ground Glass Opacities.

BACKGROUND: Lung cancers can recur locally due to inadequate resection margins. Achieving adequate margin distances is challenging in pulmonary ground glass opacities (GGOs) because they are not easily palpable. To improve margin assessment during resection of GGOs, we propose a novel technique, three-dimensional near-infrared specimen mapping (3D-NSM). METHODS: Twenty patients with a cT1 GGO were enrolled and received a fluorescent tracer preoperatively. After resection, specimens underwent 3D-NSM in the operating room. Margins were graded as positive or negative based upon fluorescence at the staple line. Images were analyzed using ImageJ to quantify the distance from the tumor edge to the nearest staple line. This margin distance calculated by 3D-NSM was compared to the margin distance reported on final pathology several days postoperatively. RESULTS: 3D-NSM identified 20/20 GGOs with no false positive or false negative diagnoses. Mean fluorescence intensity for lesions was 110.92 arbitrary units (A.U.) (IQR: 77.77-122.03 A.U.) compared to 23.68 A.U. (IQR: 19.60-27.06 A.U.) for background lung parenchyma (p < 0.0001). There were 4 tumor-positive or close margins in the study cohort, and all 4 (100%) were identified by 3D-NSM. 3D-NSM margin distances were nearly identical to margin distances reported on final pathology (R2 = 0.9362). 3D-NSM slightly under-predicted margin distance, and the median difference in margins was 1.9 mm (IQR 0.5-4.3 mm). CONCLUSIONS: 3D-NSM rapidly localizes GGOs by fluorescence and detects tumor-positive or close surgical margins. 3D-NSM can accurately quantify the resection margin distance as compared to formal pathology, which allows surgeons to rapidly determine whether sublobar resection margin distances are adequate.

Preclinical Lymph Node Model for Intraoperative Molecular Imaging of Cancer.

Purpose: Lymph node(LN) dissection is part of most oncologic resections. Intraoperatively identifying a positive LN(+ LN), that harbors malignant cells, can be challenging. We hypothesized that intraoperative molecular imaging(IMI) using a cancer-targeted fluorescent prober can identify + LNs. This study aimed to develop a preclinical model of a + LN and test it using an activatable cathepsin-based enzymatic probe, VGT-309. Procedures: In the first model, we used peripheral blood mononuclear cells (PBMC), representing the lymphocytic composition of the LN, mixed with different concentrations of human lung adenocarcinoma cell line A549. Then, they were embedded in a Matrigel® matrix. A black dye was added to mimic LN anthracosis. Model two was created using a murine spleen, the largest lymphoid organ, injected with various concentrations of A549. To test these models, we co-cultured A549 cells with VGT-309. Mean fluorescence intensity(MFI) was. An independent sample t-test was used to compare the average MFI of each A549:negative control ratio. Results: A significant difference in MFI from our PBMC control was noted when A549 cells were 25% of the LN (p = 0.046) in both 3D cell aggregate models-where the LNs native parenchyma is replaced and the one where the tumor grows over the native parenchyma. For the anthracitic equivalents of these models, the first significant MFI compared to the control was when A549 cells were 9% of the LN (p = 0.002) in the former model, and 16.7% of the LN (p = 0.033) in the latter. In our spleen model, we first noted significance in MFI when A549 cells were 16.67% of the cellular composition.(p = 0.02). Conclusions: A + LN model allows for a granular evaluation of different cellular burdens in + LN that can be assessed using IMI. This first exvivo + LN model can be used in preclinical testing of several existing dyes and in creating more sensitive cameras for IMI-guided LN detection.

Epidemiological, therapeutic, and survival trends in malignant pleural mesothelioma: A review of the National Cancer Database.

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive cancer of the cells lining the pleural cavity with a low overall incidence. The National Cancer Database (NCDB) released in August 2022 updated data that reflect the newest trends in MPM. METHODS: The NCDB was queried for patients diagnosed with MPM between 2004 and 2020. Variables collected included demographics, tumor characteristics, and treatment. Student's t-test and independent-samples proportions test were used for means analysis. Survival was assessed by the Kaplan-Meier method using SPSS version 28. RESULTS: A total of 41,074 patients were diagnosed with mesothelioma, with a steady incidence (0.25%) between 2004 and 2017. The mean age of diagnosis was 70 (SD 13). 73.2% of the patients were males, 69% had no comorbidities, and 93.3% were white. More patients were diagnosed at Stage 1 after 2008 (p < 0.001). Since 2010, there has been a significant increase in patients offered treatment with 73.9% receiving some therapy (p < 0.01): 50.5% received chemotherapy, 27.6% surgery, 8.6% radiation, and 5.4% immunotherapy. The median overall survival was 10.3 months from diagnosis [95% CI: 10.2-10.5]. Risk factors associated with 30-day mortality from surgical intervention included age (OR = 1.02, p < 0.001), male gender (OR = 1.3, p = 0.03), poorly differentiated grade (OR = 2.1, p < 0.001), Stage 4 (OR = 1.4, p = 0014), and epithelioid histology (OR = 0.51, p = 0.03). CONCLUSION: The current management of MPM is based on stage and histologic subtype. Due to the small numbers of patients at most academic centers, the NCDB provides a robust dataset to draw upon broad data points in treatment discussions with patients.

Strategies to reduce morbidity following pleurectomy and decortication for malignant pleural mesothelioma.

BACKGROUND: Pleurectomy and decortication (PD) in malignant pleural mesothelioma has a high morbidity mostly associated with aspiration pneumonia (PNA), deep vein thrombosis (DVT), and foreign catheter sepsis. We instituted four strategies to reduce these complications and report our experience. METHODS: This was a retrospective review of patients who underwent PD at the University of Pennsylvania between 2015 and 2022. Our patients underwent standard of care PD in addition to tracheostomy and gastrostomy/jejunostomy tube with therapeutic anticoagulation (AC) leading up to surgery. Measured outcomes were postoperative PNA, DVT, and sepsis. The predicted risk of those same outcomes had patients not undergone the interventions was calculated based on the American College of Surgeons (ACS) surgical risk calculator (SRC). A McNemar's test was used to determine whether the risk of having PNA, DVT and sepsis differed between the two subgroups. RESULTS: Fifty-five patients were included in the study. The mean age was 70 years (SD 6.2) with a mean of 21 (SD 19) pack-years of smoking. PNA, DVT, and catheter-related sepsis occurred in 12, four, and seven patients, respectively. Upon using the ACS SRC prediction model of the nonintervention group, PNA, DVT and catheter related sepsis was predicted to occur in 24 (paired data OR 5, 95% CI: 1.4-17.2; McNemar's test p = 0.008), 14 (paired data OR 3.5, 95% CI: 1.15-10.6; McNemar's test p = 0.03), and 17 (paired OR 3, 95% CI: 1.09-8.3; McNemar's test p = 0.04) patients, respectively. DISCUSSION: Patients undergoing tracheostomy creation, therapeutic AC at the time of diagnosis, and gastrostomy tube placement had a reduced risk of aspiration PNA, DVT, and catheter sepsis.

Cathepsin detection to identify malignant cells during robotic pulmonary resection.

Background: Intraoperative molecular imaging (IMI) uses a fluorescent probe to identify occult cancers. VGT-309 is a quenched activity-based probe that is activated in the presence of cathepsins, enzymes overexpressed in cancer cells, and detected by near-infrared (NIR) light. This study aims to evaluate the sensitivity and the positive predictive value (PPV) of robotic-assisted thoracic surgery (RATS) with intraoperative molecular imaging (RIMI) using VGT-309 to localize tumors using NIR light to detect areas with increased cathepsin activity. Our secondary outcome was to compare RIMI to video-assisted thoracic surgery (VATS) with intraoperative molecular imaging (VIMI). Methods: In a phase 2 clinical trial at the University of Pennsylvania, patients (n=10) with suspicious pulmonary lesions underwent RATS. First, white light was used followed by RIMI to identify tissues with increased cathepsin activity. Then, VIMI was performed to compare the sensitivity and PPV in identifying the cathepsin activity. The resected specimens were then evaluated for fluorescence and underwent histopathological analysis for cathepsin expression. Image analysis was performed using ImageJ software. Statistical analysis was conducted using IBM SPSS Statistics software. A P value of 0.05 or less was considered significant. Results: RATS with white light identified 6 out of the 10 pulmonary nodules, whereas adding RIMI identified an additional 4 more pulmonary nodules. RIMI and VIMI were able to detect the same 8/10 (80%) nodules. The addition of VIMI did not identify any lesions that RIMI may have missed. The mean fluorescence intensity of tumors visualized by RIMI was 115.81 A.U. [standard deviation (SD) =58.57] compared to 95.6 A.U. (SD =14.81) by VIMI (P=0.41). The mean tumor-to-background ratios (TBR) of tumors visualized by RIMI was 9.20 (SD =9.12) compared to 2.29 A.U. (SD =1.11) using VIMI (P=0.1). The sensitivity of RIMI and VIMI was 88.9% which was superior to that of RATS (55.6%). The PPV of RATS was 83.3% compared to 100% in RIMI and VIMI. Conclusions: RIMI is a valuable option for visualization of occult disease using VGT-309-guided IMI through identifying areas of increased cathepsin activity. In this small series, RIMI and VIMI showed clinical equivalence in sensitivity and PPV of detecting cathepsin activity.

Single-institution experience of 500 pulmonary resections guided by intraoperative molecular imaging.

OBJECTIVE: Intraoperative molecular imaging (IMI) using tumor-targeted optical contrast agents can improve thoracic cancer resections. There are no large-scale studies to guide surgeons in patient selection or imaging agent choice. Here, we report our institutional experience with IMI for lung and pleural tumor resection in 500 patients over a decade. METHODS: Between December 2011 and November 2021, patients with lung or pleural nodules undergoing resection were preoperatively infused with 1 of 4 optical contrast tracers: EC17, TumorGlow, pafolacianine, or SGM-101. Then, during resection, IMI was used to identify pulmonary nodules, confirm margins, and identify synchronous lesions. We retrospectively reviewed patient demographic data, lesion diagnoses, and IMI tumor-to-background ratios (TBRs). RESULTS: Five hundred patients underwent resection of 677 lesions. We found that there were 4 types of clinical utility of IMI: detection of positive margins (n = 32, 6.4% of patients), identification of residual disease after resection (n = 37, 7.4%), detection of synchronous cancers not predicted on preoperative imaging (n = 26, 5.2%), and minimally invasive localization of nonpalpable lesions (n = 101 lesions, 14.9%). Pafolacianine was most effective for adenocarcinoma-spectrum malignancies (mean TBR, 2.84), and TumorGlow was most effective for metastatic disease and mesothelioma (TBR, 3.1). False-negative fluorescence was primarily seen in mucinous adenocarcinomas (mean TBR, 1.8), heavy smokers (>30 pack years; TBR, 1.9), and tumors greater than 2.0 cm from the pleural surface (TBR, 1.3). CONCLUSIONS: IMI may be effective in improving resection of lung and pleural tumors. The choice of IMI tracer should vary by the surgical indication and the primary clinical challenge.