Red blood cells function as reservoirs of tumor DNA.

Novel screening techniques for early detection of lung cancer are urgently needed. Profiling circulating tumor cell-free DNA (ctDNA) has emerged as a promising tool for biopsy-free tumor genotyping. However, both the scarcity and short half-life of ctDNA substantially limit the sensitivity and clinical utility of ctDNA detection methodologies. Our discovery that red blood cells (RBCs) sequester mitochondrial DNA opens a new avenue for detecting circulating nucleic acids, as RBCs represent an unrecognized reservoir of circulating nucleic acid. Here, we show that RBCs acquire tumor DNA following coculture with lung cancer cell lines harboring Kirsten rat sarcoma viral oncogene homolog (KRAS) and epidermal growth factor receptor (EGFR) mutations. RBC-bound tumor DNA is detectable in patients with early-stage non-small cell lung cancer (NSCLC) but not in healthy controls by qPCR. Our results collectively uncover a previously unrecognized yet easily accessible reservoir of tumor DNA, offering a promising foundation for future RBC-based tumor diagnostics.NEW & NOTEWORTHY We present a novel method for lung cancer detection by revealing RBCs as a reservoir for tumor DNA, overcoming the limitations of current circulating tumor ctDNA methodologies. By demonstrating that RBCs can capture tumor DNA, including critical mutations found in lung cancer, we provide a promising, biopsy-free avenue for early cancer diagnostics. This discovery opens up exciting possibilities for developing RBC-based diagnostic tools, significantly enhancing the sensitivity and clinical utility of noninvasive cancer detection.

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.

Neoadjuvant Gene-Mediated Cytotoxic Immunotherapy for Non-Small-Cell Lung Cancer: Safety and Immunologic Activity.

Gene-mediated cytotoxic immunotherapy (GMCI) is an immuno-oncology approach involving local delivery of a replication-deficient adenovirus expressing herpes simplex thymidine kinase (AdV-tk) followed by anti-herpetic prodrug activation that promotes immunogenic tumor cell death, antigen-presenting cell activation, and T cell stimulation. This phase I dose-escalation pilot trial assessed bronchoscopic delivery of AdV-tk in patients with suspected lung cancer who were candidates for surgery. A single intra-tumoral AdV-tk injection in three dose cohorts (maximum 1012 viral particles) was performed during diagnostic staging, followed by a 14-day course of the prodrug valacyclovir, and subsequent surgery 1 week later. Twelve patients participated after appropriate informed consent. Vector-related adverse events were minimal. Immune biomarkers were evaluated in tumor and blood before and after GMCI. Significantly increased infiltration of CD8+ T cells was found in resected tumors. Expression of activation, inhibitory, and proliferation markers, such as human leukocyte antigen (HLA)-DR, CD38, Ki67, PD-1, CD39, and CTLA-4, were significantly increased in both the tumor and peripheral CD8+ T cells. Thus, intratumoral AdV-tk injection into non-small-cell lung cancer (NSCLC) proved safe and feasible, and it effectively induced CD8+ T cell activation. These data provide a foundation for additional clinical trials of GMCI for lung cancer patients with potential benefit if combined with other immune therapies.

A clinical trial of intraoperative near-infrared imaging to assess tumor extent and identify residual disease during anterior mediastinal tumor resection.

BACKGROUND: The management of most solid tumors of the anterior mediastinum involves complete resection. Because of their location near mediastinal structures, wide resection is not possible; therefore, surgeons must use subjective visual and tactile cues to determine disease extent. This clinical trial explored intraoperative near-infrared (NIR) imaging as an approach to improving tumor delineation during mediastinal tumor resection. METHODS: Twenty-five subjects with anterior mediastinal lesions suspicious for malignancy were enrolled in an open-label feasibility trial. Subjects were administered indocyanine green (ICG) at a dose of 5 mg/kg, 24 hours before resection (via a technique called TumorGlow). The NIR imaging systems included Artemis (Quest, Middenmeer, the Netherlands) and Iridium (VisionSense Corp, Philadelphia, Pennsylvania). Intratumoral ICG uptake was evaluated. The clinical value was determined via an assessment of the ability of NIR imaging to detect phrenic nerve involvement or incomplete resection. Clinical and histopathologic variables were analyzed to determine predictors of tumor fluorescence. RESULTS: No drug-related toxicity was observed. Optical imaging added a mean of 10 minutes to case duration. Among the subjects with solid tumors, 19 of 20 accumulated ICG. Fluorescent tumors included thymomas (n = 13), thymic carcinomas (n = 4), and liposarcomas (n = 2). NIR feedback improved phrenic nerve dissection (n = 4) and identified residual disease (n = 2). There were no false-positives or false-negatives. ICG preferentially accumulated in solid tumors; this was independent of clinical and pathologic variables. CONCLUSIONS: NIR imaging for anterior mediastinal neoplasms is safe and feasible. This technology may provide a real-time tool capable of determining tumor extent and specifically identify phrenic nerve involvement and residual disease.

Intraoperative Near-infrared Imaging Can Identify Neoplasms and Aid in Real-time Margin Assessment During Pancreatic Resection.

OBJECTIVE: To determine if intraoperative near-infrared (NIR) imaging carries benefit in resection of pancreatic neoplasms. BACKGROUND: Resection of pancreatic malignancies is hindered by high rates of local and distant recurrence from positive margins and unrecognized metastases. Improved tumor visualization could improve outcomes. We hypothesized that intraoperative NIR imaging with a clinically approved optical contrast agent could serve as a useful adjunct in assessing margins and extent of disease during pancreatic resections. METHODS: Twenty patients were enrolled in an open-label clinical trial from July 2016 to May 2018. Subjects received second window indocyanine green (ICG) (2.5-5 mg/kg) 24 hours prior to pancreatic resection. NIR imaging was performed during staging laparoscopy and after pancreas mobilization in situ and following resection ex vivo. Tumor fluorescence was quantified using tumor-to-background ratio (TBR). Fluorescence at the specimen margin was compared to pathology evaluation. RESULTS: Procedures included 9 pancreaticoduodenectomies, 10 distal pancreatectomies, and 1 total pancreatectomy; 21 total specimens were obtained. Three out of 8 noninvasive tumors were fluorescent (mean TBR 2.59 ±â€Š2.57). Twelve out of 13 invasive malignancies (n = 12 pancreatic adenocarcinoma, n = 1 cholangiocarcinoma) were fluorescent (mean TBR 4.42 ±â€Š2.91). Fluorescence at the transection margin correlated with final pathologic assessment in 12 of 13 patients. Following neoadjuvant therapy, 4 of 5 tumors were fluorescent; these 4 tumors showed no treatment response on pathology assessment. One tumor had a significant treatment response and showed no fluorescence. CONCLUSIONS: Second window ICG reliably accumulates in invasive pancreatic malignancies and provides real-time feedback during pancreatectomy. NIR imaging may help to assess the response to neoadjuvant therapy.

Identification of a Folate Receptor-Targeted Near-Infrared Molecular Contrast Agent to Localize Pulmonary Adenocarcinomas.

Non-small cell lung cancer (NSCLC) is the number one cancer killer in the United States. Despite attempted curative surgical resection, nearly 40% of patients succumb to recurrent disease. High recurrence rates may be partially explained by data suggesting that 20% of NSCLC patients harbor synchronous disease that is missed during resection. In this report, we describe the use of a novel folate receptor-targeted near-infrared contrast agent (OTL38) to improve the intraoperative localization of NSCLC during pulmonary resection. Using optical phantoms, fluorescent imaging with OTL38 was associated with less autofluorescence and greater depth of detection compared to traditional optical contrast agents. Next, in in vitro and in vivo NSCLC models, OTL38 reliably localized NSCLC models in a folate receptor-dependent manner. Before testing intraoperative molecular imaging with OTL38 in humans, folate receptor-alpha expression was confirmed to be present in 86% of pulmonary adenocarcinomas upon histopathologic review of 100 human pulmonary resection specimens. Lastly, in a human feasibility study, intraoperative molecular imaging with OTL38 accurately identified 100% of pulmonary adenocarcinomas and allowed for identification of additional subcentimeter neoplastic processes in 30% of subjects. This technology may enhance the surgeon's ability to identify NSCLC during oncologic resection and potentially improve long-term outcomes.

Surgical Management of Early-Stage Esophageal Adenocarcinoma Based on Lymph Node Metastasis Risk.

BACKGROUND: In early-stage esophageal adenocarcinoma (EAC), esophagectomy improves staging but also increases mortality compared with endoscopic resection. Our objective was to quantify esophagectomy mortality and lymph node metastasis (LNM) risk in early-stage EAC to improve surgical treatment allocation. METHODS: We identified National Cancer Database (2004-2014) patients with nonmetastatic, Tis, T1a, or T1b EAC who had primary surgical resection and microscopic examination of at least 15 lymph nodes. Univariate and multivariable logistic regression identified predictors of LNM. Cox regression identified predictors of death. The Kaplan-Meier method predicted overall survival (OS). RESULTS: In 782 patients, LNM rates were: all patients 13.8%, Tis 0%, T1a 3.6%, T1b 23.4%. Independent predictors of LNM were submucosal invasion, lymphovascular invasion (LVI), decreasing differentiation, and tumor size ≥ 2 cm (P < 0.05). For T1a tumors with poor differentiation or size ≥ 2 cm, LNM rates were 10.2 and 6.7%, respectively; 90-day mortality was 3.1%. The LNM rate in well differentiated T1b tumors < 2 cm was 4.2%; 90-day mortality was 6.0%. Estimated 5-year OS was 80.2% versus 64.4% (T1a vs. T1b). LNM increased risk of death for T1a (hazard ratio [HR] 8.52, 95% confidence interval [CI] 3.13-23.22, P < 0.001) and T1b tumors (HR 2.52, 95% CI 1.59-4.00, P < 0.001). CONCLUSIONS: In T1a EAC with poor differentiation or size ≥ 2 cm, esophagectomy should be considered, whereas in T1b EAC with low-risk features (well-differentiated T1b EAC < 2 cm without LVI), endoscopic resection may be sufficient. Treatment guidelines for early-stage EAC should include all high-risk tumor features for LNM and stage-specific esophagectomy mortality.

Intraoperative fluorescence imaging in thoracic surgery.

Intraoperative fluorescence imaging (IFI) can improve real-time identification of cancer cells during an operation. Phase I clinical trials in thoracic surgery have demonstrated that IFI with second window indocyanine green (TumorGlow® ) can identify subcentimeter pulmonary nodules, anterior mediastinal masses, and mesothelioma, while the use of a folate receptor-targeted near-infrared agent, OTL38, can improve the specificity for diagnosing tumors with folate receptor expression. Here, we review the existing preclinical and clinical data on IFI in thoracic surgery.

Near-Infrared Intraoperative Imaging Can Successfully Identify Malignant Pleural Mesothelioma After Neoadjuvant Chemotherapy.

Malignant pleural mesothelioma is a deadly disease. Complete surgical resection provides patients with the best opportunity for long-term survival. Unfortunately, identification of disease during resection can be challenging. In this report, we describe successful intraoperative utilization of the near-infrared imaging agent, indocyanine green, to help the surgeon identify malignant disease in a patient with malignant pleural mesothelioma who had previously received neoadjuvant chemotherapy. This technology may ultimately enhance the thoracic surgeon's ability to identify small disease deposits at the time of resection.

Intraoperative Molecular Imaging Combined With Positron Emission Tomography Improves Surgical Management of Peripheral Malignant Pulmonary Nodules.

OBJECTIVE: To determine if intraoperative molecular imaging (IMI) can improve detection of malignant pulmonary nodules. BACKGROUND: 18-Fluorodeoxyglucose positron emission tomography (PET) is commonly utilized in preoperative assessment of patients with solid malignancies; however, false negatives and false positives remain major limitations. Using patients with pulmonary nodules as a study model, we hypothesized that IMI with a folate receptor targeted near-infrared contrast agent (OTL38) can improve malignant pulmonary nodule identification when combined with PET. METHODS: Fifty patients with pulmonary nodules with imaging features suspicious for malignancy underwent preoperative PET. Patients then received OTL38 before pulmonary resection. During resection, IMI was utilized to evaluate known pulmonary nodules and identify synchronous lesions. Tumor size, PET standardized uptake value, and IMI tumor-to-background ratios were compared for known and synchronous nodules via paired and unpaired t tests, when appropriate. Test characteristics of PET and IMI with OTL38 were compared. RESULTS: IMI identified 56 of 59 (94.9%) malignant pulmonary nodules identified by preoperative imaging. IMI located an additional 9 malignant lesions not identified preoperatively. Nodules only detected by IMI were smaller than nodules detected preoperatively (0.5 vs 2.4 cm; P < 0.01), but displayed similar fluorescence (tumor-to-background ratio 3.3 and 3.1; P = 0.50). Sensitivity of IMI and PET were 95.6% and 73.5% (P = 0.001), respectively; and positive predictive values were 94.2% and 89.3%, respectively (P > 0.05). Additionally, utilization of IMI clinically upstaged 6 (12%) subjects and improved management of 15 (30%) subjects. CONCLUSIONS: These data suggest that combining IMI with PET may provide superior oncologic outcomes for patients with resectable lung cancer.

Clinical implications of positive margins following non-small cell lung cancer surgery.

Positive margins following pulmonary resection of non-small cell lung cancer (NSCLC) occur in approximately 5-15% of patients undergoing a curative procedure. The presence of positive margins negatively impacts long-term outcomes by setting the stage for local and potentially distant disease recurrence. Despite major clinical ramifications, there are very few dedicated reports that examine the implications of positive margins following surgery for NSCLC. Furthermore, published series are typically retrospective studies from single institutions. In this review we analyze published data with special consideration of four pertinent questions: (i) what are the long term outcomes of a positive margin following pulmonary resection?, (ii) is intraoperative margin assessment by frozen section reliable?, (iii) what is the optimal distance of the tumor margin to the surgical margin?, and (iv) should adjuvant chemotherapy and/or radiation therapy be used in the setting of a positive surgical margin?

Changes in the local tumor microenvironment in recurrent cancers may explain the failure of vaccines after surgery.

Each year, more than 700,000 people undergo cancer surgery in the United States. However, more than 40% of those patients develop recurrences and have a poor outcome. Traditionally, the medical community has assumed that recurrent tumors arise from selected tumor clones that are refractory to therapy. However, we found that tumor cells have few phenotypical differences after surgery. Thus, we propose an alternative explanation for the resistance of recurrent tumors. Surgery promotes inhibitory factors that allow lingering immunosuppressive cells to repopulate small pockets of residual disease quickly. Recurrent tumors and draining lymph nodes are infiltrated with M2 (CD11b(+)F4/80(hi)CD206(hi) and CD11b(+)F4/80(hi)CD124(hi)) macrophages and CD4(+)Foxp3(+) regulatory T cells. This complex network of immunosuppression in the surrounding tumor microenvironment explains the resistance of tumor recurrences to conventional cancer vaccines despite small tumor size, an intact antitumor immune response, and unaltered cancer cells. Therapeutic strategies coupling antitumor agents with inhibition of immunosuppressive cells potentially could impact the outcomes of more than 250,000 people each year.

Heart Transplantation for Uhl Anomaly in an Adult.

Uhl anomaly is characterized by the morphologic absence of right ventricular myocardium and is an exceedingly rare cause of nonischemic cardiomyopathy. We report the first case of a successful heart transplantation in a 41-year-old patient who presented in cardiogenic shock from Uhl anomaly causing decompensated right ventricular failure.

The timing of TGF-ß inhibition affects the generation of antigen-specific CD8+ T cells.

BACKGROUND: Transforming growth factor (TGF)-ß is a potent immunosuppressive cytokine necessary for cancer growth. Animal and human studies have shown that pharmacologic inhibition of TGF-ß slows the growth rate of established tumors and occasionally eradicates them altogether. We observed, paradoxically, that inhibiting TGF-ß before exposing animals to tumor cells increases tumor growth kinetics. We hypothesized that TGF-ß is necessary for the anti-tumor effects of cytotoxic CD8+ T lymphocytes (CTLs) during the early stages of tumor initiation. METHODS: BALB/c mice were pretreated with a blocking soluble TGF-ß receptor (sTGF-ßR, TGF-ß-blockade group, n=20) or IgG2a (Control group, n=20) before tumor inoculation. Tumor size was followed for 6 weeks. In vivo lymphocyte assays and depletion experiments were then performed to investigate the immunological basis of our results. Lastly, animals were pretreated with either sTGF-ßR (n=6) or IgG2a (n=6) prior to immunization with an adenoviral vector encoding the human papillomavirus E7 gene (Ad.E7). One week later, flow cytometry was utilized to measure the number of splenic E7-specific CD8+ T cells. RESULTS: Inhibition of TGF-ß before the injection of tumor cells resulted in significantly larger average tumor volumes on days 11, 17, 22, 26 and 32 post tumor-inoculation (p < 0.05). This effect was due to the inhibition of CTLs, as it was not present in mice with severe combined immunodeficiency (SCID) or those depleted of CD8+ T cells. Furthermore, pretreatment with sTGF-ßR inhibited tumor-specific CTL activity in a Winn Assay. Tumors grew to a much larger size when mixed with CD8+ T cells from mice pretreated with sTGF-ßR than when mixed with CD8+ T cells from mice in the control group: 96 mm3 vs. 22.5 mm3, respectively (p < 0.05). In addition, fewer CD8+ T cells were generated in Ad.E7-immunized mice pretreated with sTGF-ßR than in mice from the control group: 0.6% total CD8+ T cells vs. 1.9%, respectively (p < 0.05). CONCLUSIONS: These studies provide the first in vivo evidence that TGF-ß may be necessary for anti-tumor immune responses in certain cancers. This finding has important implications for our understanding of anti-tumor immune responses, the role of TGF-ß in the immune system, and the future development of TGF-ß inhibiting drugs.

Postoperative radiotherapy with modern techniques does not improve survival for operable stage IIIA-N2 non-small cell lung cancer.

OBJECTIVES: This study aims to evaluate whether postoperative radiotherapy using newer techniques (intensity-modulated radiotherapy [IMRT]) is associated with improved survival for patients with stage IIIA-N2 non-small cell lung cancer (NSCLC) who underwent complete resection. METHODS: The overall survival of patients with stage IIIA-N2 NSCLC who received postoperative IMRT versus no postoperative IMRT following induction chemotherapy and lobectomy in the National Cancer Database from 2010-2018 was assessed via Kaplan-Meier analysis, Cox proportional hazards analysis and propensity score-matched analysis. Additional survival analyses were also conducted in patients with completely resected stage IIIA-pN2 NSCLC who had upfront lobectomy (without induction therapy) followed by adjuvant chemotherapy alone or adjuvant chemotherapy with postoperative IMRT. Only patients receiving IMRT, which is a newer, more conformal radiotherapy technique, were included. Patients with positive surgical margins were excluded. RESULTS: A total of 3203 patients with stage IIA-N2 NSCLC who underwent lobectomy were included. Five hundred eighty-eight (18.4%) patients underwent induction chemotherapy followed by lobectomy, and 2615 (82%) underwent lobectomy followed by chemotherapy. In unadjusted, multivariable-adjusted, and propensity score--matched analyses, there were no significant differences in overall survival between the patients who also received postoperative IMRT versus those who did not. CONCLUSIONS: In this national analysis, the use of postoperative IMRT was not associated with improved survival in patients with completely resected stage IIIA-N2 NSCLC with or without induction chemotherapy.

Lobectomy for Suspected Lung Cancer Without Prior Diagnosis.

BACKGROUND: We describe use, patients, and outcome of diagnostic lobectomy for suspected lung cancer without pathologic confirmation. METHODS: A retrospective review of consecutive lobectomy or bilobectomy for suspected or confirmed primary pulmonary malignancy was conducted using our participant's sample of The Society of Thoracic Surgeons database. Surgeons performed lobectomy based on clinical diagnosis or confirmation on a biopsy specimen. Lung cancer confirmed by biopsy specimen was compared with cases clinically suspected. Univariate and multivariate analyses identified variables associated with lobectomy without biopsy specimen confirmation. RESULTS: Among 2651 lobectomies performed between 2006 and 2019 in 2617 patients, lung cancer was confirmed by preoperative biopsy specimen in 51.6% (1368 of 2651) or was clinically suspected before the operation in 48.4% (1283 of 2651). The intraoperative biopsy specimen in 585 of 1283 cases (45.6%) proved lung cancer before lobectomy, whereas lobectomy proceeded in 698 cases (54.4%) without a diagnosis. Final pathology proved lung cancer in 90% (628 of 698) without a diagnosis before lobectomy and nonmalignant disease in 10% (70 of 698). Nonneoplastic pathology included granulomas (30 of 70 [43%]), pneumonia (12 of 70 [17%]), bronchiectasis (7 of 70 [10%]), and other lesions (21 of 70 [30%]). Operative mortality was 0.94% (25 of 2651) for the cohort and 1.0% (7 of 698) for diagnostic lobectomy only. Multivariate analysis identified patient age, type of lobectomy (right middle lobe), and the intermediate study tercile as associated with diagnostic lobectomy. CONCLUSIONS: Lobectomy for suspected lung cancer without diagnosis is common, represents practice variation, and infrequently (10% diagnostic, 2.6% all lobectomies) removes nonmalignant disease. Tissue confirmation before lobectomy is preferred, particularly when operative risk is increased. Diagnostic lobectomy is acceptable in carefully selected patients and lesions.

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.

Multiinstitutional Phase 2 Clinical Trial of Intraoperative Molecular Imaging of Lung Cancer.

BACKGROUND: Intraoperative molecular imaging (IMI) may improve surgical outcomes during pulmonary resection for lung cancer. A multiinstitutional phase 2 IMI clinical trial was conducted using a near-infrared, folate receptor-targeted contrast agent for lung adenocarcinomas, OTL38. The primary goal was to determine whether OTL38 improved surgeons' ability to identify difficult to find nodules, occult cancers, and positive margins. METHODS: Patients with lung nodules received OTL38 (0.025 mg/kg) preoperatively. Patients had IMI sequentially during lung inspection, tumor resection, and margin check. Efficacy was evaluated by occurrence of clinically significant events, occurrences that caused the surgeon to modify the operation or upstage the patient's cancer. Safety was assessed for a single intravenous dose of OTL38. RESULTS: Of 110 patients recruited, 92 were eligible for analysis. During lung inspection, IMI found 24 additional nodules, 9 (10%) of which were cancers that had not been known preoperatively. During tumor resection, IMI located 11 (12%) lesions that the surgeon could not find. During the margin check, IMI revealed 8 positive margins (9%) that the surgeon thought were negative. Benefits of IMI were pronounced in patients undergoing sublobar pulmonary resections and in patients with ground-glass opacities. There were no serious adverse events. All surgeons felt comfortable with the procedures by 10 cases. CONCLUSIONS: In this phase 2 clinical trial, IMI improved outcomes for 26% of patients. A randomized, multiinstitutional phase 3 clinical trial is underway.

Intraoperative Molecular Imaging Utilizing a Folate Receptor-Targeted Near-Infrared Probe Can Identify Macroscopic Gastric Adenocarcinomas.

PURPOSE: Current methods of assessing disease burden in gastric adenocarcinoma are imperfect. Improved visualization during surgery with intraoperative molecular imaging (IMI) could improve gastric adenocarcinoma staging and guide surgical decision-making. The goal of this study was to evaluate if IMI with a folate receptor-targeted near-infrared fluorescent agent, OTL38, could identify gastric adenocarcinomas during surgery. PROCEDURES: Five patients were enrolled in an IMI clinical trial. Patients received a folate receptor-targeted near-infrared dye (OTL38) 1.5-6 h prior to surgery. During staging laparoscopy and gastric resection, IMI was utilized to identify the primary tumor and any fluorescent lymph nodes. Resected tumors were analyzed for folate receptor alpha (FRα) and CD68 expression using immunohistochemistry. Microscopic OTL38 accumulation was examined with immunofluorescence. RESULTS: Four out of five patients underwent total or subtotal gastrectomy; one had a staging laparoscopy only. All four patients who underwent gastric resection had invasive gastric adenocarcinoma; three had fluorescent tumors, mean tumor to background ratio (TBR) 4.1 ± 2.9. The one patient with a non-fluorescent tumor had a T1a tumor with two 0.4 cm tumor foci within a larger polyp. In each case with a fluorescent tumor, the fluorescence was evident from the exterior of the stomach. Two of the fluorescent tumors had modest FRα expression and no CD68 expression. One fluorescent tumor had high CD68 expression and no FRα expression. CONCLUSIONS: Intraoperative molecular imaging of gastric adenocarcinoma with OTL38 is feasible. Further studies should evaluate the clinical utility of this technique.