Intraoperative Detection and Assessment of Lung Nodules

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.

Comparison of laser guidance and freehand hook-wire for CT-guided preoperative localization of pulmonary nodules

PURPOSE

In VATS surgery, precise preoperative localization is particularly crucial when dealing with small-diameter pulmonary nodules located deep within the lung parenchyma. The purpose of this study was to compare the efficacy and safety of laser guidance and freehand hook-wire for CT-guided preoperative localization of pulmonary nodules.

METHODS

This retrospective study was conducted on 164 patients who received either laser guidance or freehand hook-wire localization prior to Uni-port VATS from September 1st, 2022 to September 30th, 2023 at The First Affiliated Hospital of Soochow University. Patients were divided into laser guidance group and freehand group based on which technology was used. Preoperative localization data from all patients were compiled. The localization success and complication rates associated with the two groups were compared. The risk factors for common complications were analyzed.

RESULTS

The average time of the localization duration in the laser guidance group was shorter than the freehand group (p<0.001), and the average CT scan times in the laser guidance group was less than that in the freehand group (p<0.001). The hook-wire was closer to the nodule in the laser guidance group (p<0.001). After the localization of pulmonary nodules, a CT scan showed 14 cases of minor pneumothorax (22.58%) in the laser guidance group and 21 cases (20.59%) in the freehand group, indicating no statistical difference between the two groups (p=0.763). CT scans in the laser guidance group showed pulmonary minor hemorrhage in 8 cases (12.90%) and 6 cases (5.88%) in the freehand group, indicating no statistically significant difference between the two groups (p=0.119). Three patients (4.84%) in the laser guidance group and six patients (5.88%) in the freehand group had hook-wire dislodgement, showing no statistical difference between the two groups (p=0.776).

CONCLUSION

The laser guidance localization method possessed a greater precision and less localization duration and CT scan times compared to the freehand method. However, laser guidance group and freehand group do not differ in the appearance of complications such as pulmonary hemorrhage, pneumothorax and hook-wire dislodgement.

[Intraoperative near-infrared fluorescence imaging of peripheral lung tumors]

The main objective of surgical intervention in lung cancer is the radical removal of the entire tumor with the maximum possible preservation of healthy tissue. Although the area of the tumor lesion is known by the results of preoperative studies, it can be difficult to use this information to establish the exact boundaries of resection during surgery, especially with small sizes of the lump and when using minimally invasive approaches. There are several techniques to solve this problem. One of the latter is intraoperative fluorescence imaging in the infrared range, which makes it possible to detect a tumor not only with greater contrast than it can be done in white light, but also with its deep location. This review is devoted to the discussion of various aspects of this approach related to molecular imaging methods. The current situation based on the use of green indocyanine green, available for clinical use as a fluorescent agent is considered, the issues of using new targeted drugs are examined, as well as the possibility of increasing the depth of probing and combining with related treatment methods, which should contribute to a more radical operation and reduce the likelihood of local relapses.

A pH-Activatable Nanoprobe Labels Diverse Histologic Subtypes of Human Lung Cancer During Resection

BACKGROUND

Intraoperative molecular imaging (IMI) uses tumor-targeted optical contrast agents to improve identification and clearance of cancer during surgery. Recently, pH-activatable contrast agents have been developed but none has been tested in lung cancer. Here, we report the successful clinical translation of pegsitacianine (ONM-100), a pH-activatable nanoprobe, for fluorescence-guided lung cancer resection.

METHODS

We first characterized the pH setpoint for pegsitacianine fluorescence activation in vitro. We then optimized the specificity, dosing, and timing of pegsitacianine in murine flank xenograft models of lung adenocarcinoma and squamous cell carcinoma. Finally, we tested pegsitacianine in humans undergoing lung cancer surgery as part of an ongoing phase 2 trial.

RESULTS

We found that the fluorescence activation of pegsitacianine occurred below physiologic pH in vitro. Using preclinical models of lung cancer, we found that the probe selectively labeled both adenocarcinoma and squamous cell carcinoma xenografts (mean tumor-to-background ratio [TBR] > 2.0 for all cell lines). In the human pilot study, we report cases in which pegsitacianine localized pulmonary adenocarcinoma and pulmonary squamous cell carcinoma (TBRs= 2.7 and 2.4) in real time to illustrate its successful clinical translation and potential to improve surgical management.

CONCLUSIONS

This translational study demonstrates the feasibility of pegsitacianine as an IMI probe to label the two most common histologic subtypes of human lung cancer.

Sodium Multivitamin Transporter-Targeted Fluorochrome Facilitates Enhanced Metabolic Evaluation of Tumors Through Coenzyme-R Dependent Intracellular Signaling Pathways

BACKGROUND

Intraoperative molecular imaging (IMI)-guided resections have been shown to improve oncologic outcomes for patients undergoing surgery for solid malignancies. The technology utilizes fluorescent tracers targeting cancer cells without the use of any ionizing radiation. However, currently available targeted IMI tracers are effective only for tumors with a highly specific receptor expression profile, and there is an unmet need for IMI tracers to label a broader range of tumor types. Here, we describe the development and testing of a novel tracer (CR)-S0456) targeted to the sodium multivitamin transporter (SMVT).

METHODS

Preclinical models of fibrosarcoma (HT-1080), lung (A549), breast (4T1), and renal cancers (HEK-293 T) in vitro and in vivo were used for assessment of (CR)-S0456 specific tumor labeling via sodium-mediated SMVT uptake in dipotassium phosphate or choline chloride-containing media buffer. Additionally, pharmacologic inhibition of multiple intracellular coenzyme-R obligate signaling pathways, including holocarboxylase synthetase (sulconazole nitrate), PI3K/AKT/mTOR (omipalisib), and calmodulin-dependent phosphatase (calmidazolium), were investigated to assess (CR)-S0456 uptake kinetics. Human fibrosarcoma-bearing xenografts in athymic nude mice were used for tumor and metabolic-specific labeling. Novel NIR needle confocal laser endomicroscopic (nCLE) intratumoral sampling was performed to demonstrate single-cell specific labeling by CR-S0456.

RESULTS

CR-S0456 localization in vitro correlated with highly proliferative cell lines (MTT) and doubling time (p < 0.05) with the highest microscopic fluorescence detected in aggressive human fibrosarcomas (HT-1080). Coenzyme-R-specific localization was demonstrated to be SMVT-specific after competitive inhibition of internal localization with excess administration of pantothenic acid. Inhibiting the activity of SMVT by affecting sodium ion hemostasis prevented the complete uptake of CR-S0456. In vivo validation demonstrated (CR)-S0456 localization to xenograft models with accurate identification of primary tumors as well as margin assessment down to 1 mm3 tumor volume. Systemic treatment of xenograft-bearing mice with a dual PI3K/mTOR inhibitor suppressed intratumoral cell signaling and (CR)-S0456 uptake via a reduction in SMVT expression. Novel analysis of in vivo intratumoral cytologic fluorescence using near-infrared confocal laser endomicroscopy demonstrated the absence of coenzyme-R-mediated NIR fluorescence but not fibroblast activation protein (FAP)-conjugated fluorochrome, indicating specific intracellular inhibition of coenzyme-R obligate pathways.

CONCLUSION

These findings suggest that a SMVT-targeted NIR contrast agent can be a suitable tracer for imaging a wide range of malignancies as well as evaluating metabolic response to systemic therapies, similar to PET imaging with immune checkpoint inhibitors.

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.

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.

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.

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.

Carcinoembryonic Antigen-Related Cell Adhesion Molecule Type 5 Receptor-Targeted Fluorescent Intraoperative Molecular Imaging Tracer for Lung Cancer: A Nonrandomized Controlled Trial

Importance

Localization of subcentimeter ground glass opacities during minimally invasive thoracoscopic lung cancer resections is a significant challenge in thoracic oncology. Intraoperative molecular imaging has emerged as a potential solution, but the availability of suitable fluorescence agents is a limiting factor.

Objective

To evaluate the suitability of SGM-101, a carcinoembryonic antigen-related cell adhesion molecule type 5 (CEACAM5) receptor-targeted near-infrared fluorochrome, for molecular imaging-guided lung cancer resections, because glycoprotein is expressed in more than 80% of adenocarcinomas.

Design, Setting, and Participants

For this nonrandomized, proof-of-principal, phase 1 controlled trial, patients were divided into 2 groups between August 1, 2020, and January 31, 2022. Patients with known CEACAM5-positive gastrointestinal tumors suggestive of lung metastasis were selected as proof-of-principle positive controls. The investigative group included patients with lung nodules suggestive of primary lung malignant neoplasms. Patients 18 years or older without significant comorbidities that precluded surgical exploration with suspicious pulmonary nodules requiring surgical biopsy were included in the study.

Interventions

SGM-101 (10 mg) was infused up to 5 days before index operation, and pulmonary nodules were imaged using a near-infrared camera system with a dedicated thoracoscope.

Main Outcomes and Measures

SGM-101 localization to pulmonary nodules and its correlation with CEACAM5 glycoprotein expression by the tumor as quantified by tumor and normal pulmonary parenchymal fluorescence.

Results

Ten patients (5 per group; 5 male and 5 female; median [IQR] age, 66 [58-69] years) with 14 total lesions (median [range] lesion size, 0.91 [0.90-2.00] cm) were enrolled in the study. In the control group of 4 patients (1 patient did not undergo surgical resection because of abnormal preoperative cardiac clearance findings that were not deemed related to SGM-101 infusion), the mean (SD) lesion size was 1.33 (0.48) cm, 2 patients had elevated serum CEA markers, and 2 patients had normal serum CEA levels. Of the 4 patients who underwent surgical intervention, those with 2+ and 3+ tissue CEACAM5 expression had excellent tumor fluorescence, with a mean (SD) tumor to background ratio of 3.11 (0.45). In the patient cohort, the mean (SD) lesion size was 0.68 (0.22) cm, and no elevations in serum CEA levels were found. Lack of SGM-101 fluorescence was associated with benign lesions and with lack of CEACAM5 staining.

Conclusions and Relevance

This in-human proof-of-principle nonrandomized controlled trial demonstrated SGM-101 localization to CEACAM5-positive tumors with the detection of real-time near-infrared fluorescence in situ, ex vivo, and by immunofluorescence microscopy. These findings suggest that SGM-101 is a safe, receptor-specific, and feasible intraoperative molecular imaging fluorochrome that should be further evaluated in randomized clinical trials.

Trial Registration

ClinicalTrials.gov identifier: NCT04315467.

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.

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.

Comparison of hook-wire and medical glue for CT-guided preoperative localization of pulmonary nodules

Background

Preoperative localization is challenging due to the small diameter of pulmonary nodules or their deep location in the lung parenchyma during VATS surgery. The purpose of this study was to compare the efficacy and safety of both hook-wire and medical glue for pre-operative localization of pulmonary nodules.

Methods

In the current study, 158 patients were retrospectively analyzed (January 2019 and January 2020). The patients underwent hook-wire or medical glue for pre-operative localization of pulmonary nodules. Among them, 74 patients in the hook-wire group and 84 patients in the medical glue group underwent VATS anatomic segmentectomy or wedge resection after localization of pulmonary nodules. Pre-operative localization data from all patients were compiled. Moreover, the efficacy and safety of the two methods were evaluated according to localization success rates and localization-related complications.

Results

The success rate of localization in the medical glue group was 100% while 97.3% in the hook-wire group. After localization of the pulmonary nodules, the incidence of minor pneumothorax in the medical glue group (11.9%) was lower than that in the hook-wire group (37.8%) (p=0.01). The incidence of mild pulmonary parenchymal hemorrhage in the medical glue group (13.1%) was also lower than that in the hook-wire group (24.3%) (p=0.000). The mean time from the completion of localization to the start of surgery was also longer in the medical glue group than in the hook-wire group (p=0.000). The mean visual analog scale (VAS) scores after localization were higher in the hook-wire group than in the medical glue group (p=0.02). In both groups, parenchymal hemorrhage was significantly associated with the needle length in hook-wire localization and the depth of the medical glue in the lung parenchyma (p = 0.009 and 0.001, respectively).

Conclusion

These two localization methods are safe and effective in pre-operative pulmonary nodule localization. The medical glue localization method had a lower risk of complications, a higher localization success rate, less pain after localization and more flexibility in the arrangement of operation time.

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.

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-022-05868-9.

Impact of Intraoperative Molecular Imaging after Fluorescent-Guided Pulmonary Metastasectomy for Sarcoma

BACKGROUND

Intraoperative molecular imaging (IMI) has been shown to improve lesion detection during pulmonary sarcomatous metastasectomy. Our goal in this study was to evaluate whether data garnered from IMI-guided resection of pulmonary sarcoma metastasis translate to improved patient outcomes.

STUDY DESIGN

Fifty-two of 65 consecutive patients with a previous history of sarcomas found to have pulmonary nodules during screening were enrolled in a nonrandomized clinical trial. Patients underwent TumorGlow the day before surgery. Data on patient demographics, tumor biologic characteristics, preoperative assessment, and survival were included in the study analysis and compared with institutional historical data of patients who underwent metastasectomy without IMI. p values < 0.05 were considered significant.

RESULTS

IMI detected 42 additional lesions in 31 patients (59%) compared with the non-IMI cohort where 25% percent of patients had additional lesions detected using tactile and visual feedback only (p < 0.05). Median progression-free survival (PFS) for patients with IMI-guided pulmonary sarcoma metastasectomy was 36 months vs 28.6 months in the historical cohort (p < 0.05). IMI-guided pulmonary sarcoma metastasectomy had recurrence in the lung with a median time of 18 months compared with non-IMI group at 13 months (p < 0.05). Patients with synchronous lesions in the IMI group underwent systemic therapy at a statistically higher rate and tended to undergo routine screening at shorter interval.

CONCLUSIONS

IMI identifies a subset of sarcoma patients during pulmonary metastasectomy who have aggressive disease and informs the medical oncologist to pursue more aggressive systemic therapy. In this setting, IMI can serve both as a diagnostic and prognostic tool without conferring additional risk to the patient.

A Prostate-Specific Membrane Antigen-Targeted Near-Infrared Conjugate for Identifying Pulmonary Squamous Cell Carcinoma during Resection

Pulmonary squamous cell carcinoma is the second most common lung cancer subtype and has a low 5-year survival rate at 17.6%. Complete resection with negative margins can be curative, but a high number of patients suffer early postoperative recurrence due to inadequate disease clearance at the index operation. Intraoperative molecular imaging (IMI) with tumor-targeted optical contrast agents is effective in improving resection completeness for other tumor types, but there are no IMI tracers targeted to pulmonary squamous cell carcinoma. In this report, we describe the use of a novel prostate-specific membrane antigen (PSMA)-targeted near-infrared conjugate (OTL78) to identify pulmonary squamous cell carcinoma. We identified PSMA as a viable target by examining its expression in human lung tumor specimens from a surgical cohort. Ninety-four percent of tumors expressed PSMA in either the pulmonary squamous cells or the tumor neovasculature. Using in vitro and in vivo models, we found that OTL78 reliably localized pulmonary squamous cell carcinoma in a PSMA-dependent manner. Finally, we found that IMI with OTL78 markedly improved surgeons' ability to identify residual disease after surgery in a preclinical model. Ultimately, this novel optical tracer may aid surgical resection of pulmonary squamous cell carcinoma and potentially improve long-term outcomes.

3D Specimen Mapping Expedites Frozen Section Diagnosis of Non-Palpable Ground Glass Opacities

BACKGROUND

Pulmonary ground glass opacities (GGOs) are early-stage adenocarcinoma spectrum lesions that are not easily palpable. Challenges in localizing GGOs during intraoperative pathology can lead to imprecise diagnoses and additional time under anesthesia. To improve localization of GGOs during frozen section diagnosis, we evaluated a novel technique, three-dimensional near-infrared specimen mapping (3D-NSM).

METHODS

Fifty-five patients with a cT1 GGO were enrolled and received a fluorescent tracer preoperatively. After resection, specimens were inspected to identify lesions. Palpable and non-palpable nodules underwent 3D-NSM and the area of highest fluorescence was marked with a suture. Time for 3D-NSM, time for frozen section diagnosis, and number of tissue sections examined were recorded. To compare 3D-NSM to standard-of-care techniques, a control cohort of twenty subjects with identical inclusion criteria were enrolled. Specimens did not undergo 3D-NSM and were sent directly to pathology.

RESULTS

3D-NSM localized 54/55 lesions with one false negative. All 41 palpable lesions were identified by 3D-NSM. Thirteen of 14 non-palpable lesions (92.8%) were located by 3D-NSM. Time to diagnosis for the 3D-NSM cohort was 23.5 minutes, compared to 26.0 minutes in the control cohort (p=0.04). 3D-NSM did not affect time to diagnosis of palpable lesions (23.2 min vs. 21.4 minutes, p=0.10). 3D-NSM significantly reduced time to diagnosis for non-palpable lesions (t=23.3 min vs. 34.4 minutes, p<0.0001). 3D-NSM also reduced the number of tissue sections analyzed in non-palpable lesions (4.50 vs. 11.00, p<0.0001).

CONCLUSIONS

3D-NSM accurately localizes GGOs and expedites intraoperative diagnosis by reducing the number of tissue sections analyzed for non-palpable GGOs.

Intraoperative molecular imaging clinical trials: a review of 2020 conference proceedings

SIGNIFICANCE

Surgery is often paramount in the management of many solid organ malignancies because optimal resection is a major factor in disease-specific survival. Cancer surgery has multiple challenges including localizing small lesions, ensuring negative surgical margins around a tumor, adequately staging patients by discriminating positive lymph nodes, and identifying potential synchronous cancers. Intraoperative molecular imaging (IMI) is an emerging potential tool proposed to address these issues. IMI is the process of injecting patients with fluorescent-targeted contrast agents that highlight cancer cells prior to surgery. Over the last 5 to 7 years, enormous progress has been achieved in tracer development, near-infrared camera approvals, and clinical trials. Therefore, a second biennial conference was organized at the University of Pennsylvania to gather surgical oncologists, scientists, and experts to discuss new investigative findings in the field. Our review summarizes the discussions from the conference and highlights findings in various clinical and scientific trials.

AIM

Recent advances in IMI were presented, and the importance of each clinical trial for surgical oncology was critically assessed. A major focus was to elaborate on the clinical endpoints that were being utilized in IMI trials to advance the respective surgical subspecialties.

APPROACH

Principal investigators presenting at the Perelman School of Medicine Abramson Cancer Center's second clinical trials update on IMI were selected to discuss their clinical trials and endpoints.

RESULTS

Multiple phase III, II, and I trials were discussed during the conference. Since the approval of 5-ALA for commercial use in neurosurgical malignancies, multiple tracers and devices have been developed to address common challenges faced by cancer surgeons across numerous specialties. Discussants also presented tracers that are being developed for delineation of normal anatomic structures that can serve as an adjunct during surgical procedures.

CONCLUSIONS

IMI is increasingly being recognized as an improvement to standard oncologic surgical resections and will likely advance the art of cancer surgery in the coming years. The endpoints in each individual surgical subspecialty are varied depending on how IMI helps each specialty solve their clinical challenges.