Intraoperative Sentinel Node Mapping with Technitium-99 in Lung Cancer: Results of CALGB 140203 Multicenter Phase II Trial

Clinicopathological factors associated with sentinel lymph node detection in non-small-cell lung cancer

BACKGROUND

Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging might not always identify the first lymph node relay. The aim of this study was to determine the clinicopathologic factors allowing the identification of sentinel lymph nodes (SLNs) by NIR fluorescence imaging in thoracic surgery for non-small-cell lung cancer (NSCLC).

METHODS

We conducted a retrospective review of 92 patients treated for suspected or confirmed cN0 lung cancer with curative intent who underwent an intraoperative injection of indocyanine green (ICG) either by direct peritumoral injection or by endobronchial injection using electromagnetic navigational bronchoscopy (ENB). After exclusion of patients for technical failure, benign disease and metastasis, we analyzed the clinicopathologic findings of 65 patients treated for localized-stage NSCLC, comparing the group with identification of SLNs (SLN-positive group) with the group without identification of SLNs (SLN-negative group).

RESULTS

Forty-eight patients (73.8%) were SLN-positive. Patients with SLN positivity were more frequently female (50%) than the SLN-negative patients were (11.8%) (p = 0.006). The mean value of diffusing capacity for carbon monoxide (DLCO) was lower among the patients in the SLN-negative group (64.7% ± 16.7%) than the SLN-positive group (77.6% ± 17.2%, p < 0.01). The ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FCV) was higher in the SLN-positive group (69.0% vs. 60.8%, p = 0.02). Patients who were SLN-negative were characterized by a severe degree of emphysema (p = 0.003). There was no significant difference in pathologic characteristics. On univariate analyses, age, female sex, DLCO, FEV1/FVC, degree of emphysema, and tumor size were significantly associated with SLN detection. On multivariate analysis, DLCO > 75% (HR = 4.92, 95% CI: 1.27-24.7; p = 0.03) and female sex (HR = 5.55, 95% CI: 1.25-39.33; p = 0.04) were independently associated with SLN detection.

CONCLUSIONS

At a time of resurgence in the use of the sentinel lymph node mapping technique in the field of thoracic surgery, this study enabled us to identify, using multivariate analysis, two predictive factors for success: DLCO > 75% and female sex. Larger datasets are needed to confirm our results.

Intraoperative ultrasound: "Alternative eye" in lymph nodal dissection in non-small cell lung cancer

INTRODUCTION

Staging of the mediastinum lymph nodes involvement in patients with non-small cell lung cancer (NSCLC) is an important prognostic factor determining the most appropriate multimodality treatment plan. The objective of this study is to assess ultrasound characteristics of mediastinal lymph nodes metastasis and effectiveness of intraoperative ultrasound-guided mediastinal nodal dissection in patients with resected NSCLC.

MATERIALS AND METHODS

All patients undergoing video-assisted thoracoscopic surgery lobectomy and pulmonary lymphadenectomy from November 2020 to March 2022 at the thoracic surgery department of the Vanvitelli University of Naples underwent intraoperative ultrasound-guided mediastinal lymph nodal dissection.

RESULTS

This study evaluates whether individual B-mode features and a compounding thereof can be used to accurately and reproducibly predict lymph node malignancy.

DISCUSSION

Intraoperative ultrasound, during systematic mediastinal lymph node dissection, is helpful in preventing lesion to mediastinal structures. Pathological nodal sonographic characteristics are round shape, short-axis diameter, echogenicity, margin, the absence or presence of coagulation necrosis sign, and the absence or presence of central hilar structure, increased color Doppler flow, the absence or presence of calcification, and nodal conglomeration. Operating time was not substantially prolonged. The procedure is simple, safe and highly accurate.

CONCLUSIONS

Ultrasonic techniques allow surgeons to detect the relationship between lymph nodes and surrounding large blood vessels during biopsy, improving the safety and simplicity of the operation, increasing the number of harvested lymph nodes, and reducing the risk of intraoperative injury; it is a fast, easily reproducible, and inexpensive method.

The lymphatic system and sentinel lymph nodes: conduit for cancer metastasis

The lymphatic system is a complicated system consisting of the lymphatic vessels and lymph nodes draining the extracellular fluid containing cellular debris, excess water and toxins to the circulatory system. The lymph nodes serve as a filter, thus, when the lymph fluid returns to the heart, it is completely sterile. In addition, the lymphatic system includes the mucosa-associated lymphoid tissue, such as tonsils, adenoids, Peyers patches in the small bowel and even the appendix. Taking advantage of the drainage system of the lymphatics, cancer cells enter the lymphatic vessels and then the lymph nodes. In general, the lymph nodes may serve as a gateway in the majority of cases in early cancer. Occasionally, the cancer cells may enter the blood vessels. This review article emphasizes the structural integrity of the lymphatic system through which cancer cells may spread. Using melanoma and breast cancer sentinel lymph node model systems, the spread of early cancer through the lymphatic system is progressive in a majority of cases. The lymphatic systems of the internal organs are much more complicated and difficult to study. Knowledge from melanoma and breast cancer spread to the sentinel lymph node may establish the basic principles of cancer metastasis. The goal of this review article is to emphasize the complexity of the lymphatic system. To date, the molecular mechanisms of cancer spread from the cancer microenvironment to the sentinel lymph node and distant sites are still poorly understood and their elucidation should take major priority in cancer metastasis research.

Long-term outcomes of sentinel node identification using indocyanine green in patients with lung cancer

BACKGROUND

Sentinel node (SN) biopsy is used in the management of numerous cancers to avoid unnecessary lymphadenectomy. This was a clinical exploration/feasibility study of a novel identification technique for SN biopsy using indocyanine green (ICG) fluorescence imaging during lung cancer surgery.

METHODS

SN biopsy using ICG was performed on 22 patients who had cT1 or T2N0M0 lung cancer. ICG was injected just around the primary tumor. The fluorescence imaging system enabled visualization of the lymphatic vessels draining from the primary tumor toward the lymph nodes. Fluorescently labeled nodes were dissected, and patients were followed-up for prognosis and recurrence to confirm the pattern of lymph node metastasis after surgery.

RESULTS

SNs were successfully identified in 16 (72.7%) of 22 patients. A total of 13 of 16 patients had pathological N0 and three had SN metastasis. The median follow-up time was 92.7 months. Only one patient had no SN metastasis at the postoperative pathological examination and lymph node metastasis during the follow-up period. The accuracy rate was 93.8% (15/16) and the false-negative rate was 7.7% (1/13).

CONCLUSIONS

SNs were identified by ICG fluorescence imaging, and this technique during lung cancer surgery had good identification and accuracy rates throughout the follow-up period.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: We attempted to identify sentinel lymph nodes by indocyanine green in lung cancer surgery. The identification rate was 72.7%. The accuracy rate was 100% immediately after surgery, and 93.8% after follow-up.

WHAT THIS STUDY ADDS

Sentinel node biopsy by indocyanine green may be useful for lymph node dissection during lung cancer surgery to avoid unnecessary lymphadenectomy.

Finding the "True" N0 Cohort: Technical Aspects of Near-infrared Sentinel Lymph Node Mapping in Non-small Cell Lung Cancer

OBJECTIVE

To examine technical-, patient-, tumor-, and treatment-related factors associated with NIR guided SLN identification.

BACKGROUND

Missed nodal disease correlates with recurrence in early stage NSCLC. NIR-guided SLN mapping may improve staging and outcomes through identification of occult nodal disease.

METHODS

Retrospective analysis of 2 phase I clinical trials investigating NIR-guided SLN mapping utilizing ICG in patients with surgically resectable NSCLC.

RESULTS

In total, 66 patients underwent NIR-guided SLN mapping and lymphadenectomy after peritumoral ICG injection. There was significantly increased likelihood of SLN identification with injection dose ≥1 mg compared to <1 mg (65.2% vs 35.0%, P = 0.05), lung ventilation after injection (65.2% vs 35.0%, P = 0.05), and albumin dissolvent (68.1%) compared to fresh frozen plasma (28.6%) and sterile water (20.0%) (P = 0.01). In patients receiving the optimized ICG injection, there was significantly increased likelihood of SLN identification with radiologically solid nodules compared to sub-solid nodules (77.4% vs 33.3%, P = 0.04) and anatomic resection compared to wedge resection (88.2% vs 52.2%, P = 0.04). Disease-free and overall survival are 100% in those with a histologically negative SLN identified (n = 25) compared to 73.6% (P = 0.02) and 63.6% (P = 0.01) in patients with node negative NSCLC established via routine lymphadenectomy alone (n = 22).

CONCLUSIONS

SLN(s) are more reliably identified with ICG dose ≥1 mg, albumin dissolvent, post-injection lung ventilation, radiologically solid nodules, and anatomic resections. To date, N0 status when established via NIR SLN mapping seems to be associated with decreased recurrence and improved survival after surgery for NSCLC.

Sentinel lymph node biopsy for lung cancer

Sentinel lymph node biopsy is a technique to identify the first lymph node (or nodes) draining a tumor. The underlying principle is that as the first site of cancer spread, evaluation of the sentinel node will be most predictive for wider nodal involvement. The introduction of sentinel node biopsy revolutionized the surgical management of cutaneous melanoma and breast cancer, becoming a key component in the management of such patients. For over 20 years, thoracic surgeons have similarly worked to apply this technique to lung cancer but have thus far not had the same impact on lung surgery. In this review, we will summarize the ongoing discussions on the role of sentinel node biopsy in lung cancer, the methods for identifying the sentinel node, and the techniques for evaluating the sentinel node specimen. We will also highlight some of the pressing questions investigators should consider when designing a trial for sentinel node mapping. This will clarify the current status of sentinel node biopsy in lung cancer and thus highlight important future directions for research.

Diagnostic accuracy of sentinel lymph node biopsy using indocyanine green in lung cancer: a systematic review and meta-analysis

OBJECTIVE

The use of sentinel lymph node biopsy (SLNB) has been gaining popularity with the emergence of indocyanine green (ICG) fluorescence imaging. We aimed to systematically review the literature and perform a meta-analysis on the diagnostic accuracy of SLNB using ICG for lung cancer.

METHODS

A comprehensive search of MEDLINE, EMBASE, SCOPUS, Web of Science, and the Cochrane Library using search terms "lung/pulmonary" AND "tumor/carcinoma/cancer/neoplasm/adenocarcinoma/malignancy/squamous/carcinoid" AND "indocyanine green" was completed in June 2018. Articles were selected based on the following inclusion criteria: (1) diagnostic accuracy study design; (2) ICG injected at the tumor site with near-infrared fluorescence imaging identification of sentinel lymph nodes; (3) lymphadenectomy or sampling was performed as the gold standard.

RESULTS

Eight primary studies were included with a total of 366 patients. 43.0% of patients were females and the mean tumor size was 2.3 cm. Sentinel lymph nodes were identified with ICG in 251 patients, yielding a pooled identification rate of 0.83 (0.67-0.94). A meta-analysis of seven studies computed a diagnostic odds ratio, sensitivity, and specificity of 177.6 (45.6-691.1), 0.85 (0.71-0.94), and 1.00 (0.98-1.00), respectively. The summary receiver operator characteristic demonstrated an area under the curve of 0.963 (SE = 0.038) and a Q* of 0.91 (SE = 0.057).

CONCLUSION

Our review found suboptimal results for the diagnostic accuracy of SLNB using ICG and must be improved before routine clinical use. Further research is required to develop a robust protocol for the use SLNB with ICG for lung cancer.

[Rationale of thoracic lymph node dissection in pulmonary metastasectomy]

The goal of metastasectomy is a R0 resection. Depending of the tumor entity the prevalence of lymph node metastases in pulmonary metastasectomy can be up to 45%; however, systematic lymph node dissection is not yet established as a fixed component of metastasectomy. Although there is a high prevalence of lymph node metastases and the increase in the prevalence with a higher number of lung metastases, it remains unclear if a systematic lymph node dissection should be part of pulmonary metastasectomy. For this reason, the goal of this review was to evaluate the rationale of systematic lymph node dissection in pulmonary metastasectomy based on the currently available literature. Furthermore, it was investigated whether patients with additional thoracic lymph node metastases should be excluded per se from pulmonary metastasectomy, even though positive lymph node metastases might be associated with a lower but nevertheless good long-term survival after resection.

Clinical Significance of Molecular Micrometastasis in the Sentinel Lymph Node of Early-stage Non-Small Cell Lung Cancer Patients

OBJECTIVES

Metastatic affectation of lymph node is the main prognostic factor in localized lung cancer. A pathologic study of the obtained samples, even after adequate lymphadenectomy, showed tumor relapses for 20% of stage I patients after oncological curative surgery. We evaluated the prognostic value of molecular micrometastasis in the sentinel lymph node of patients with early-stage lung cancer.

PATIENTS AND METHODS

The sentinel node was marked immediately after performing thoracotomy by peritumorally injecting 0.25 mCi of nanocoloid of albumin (Nanocol1) labeled with Tc-99m in 0.3 mL. Guided by a Navigator1 gammagraphic sensor, we proceeded to its resection. The RNA of the tissue was extracted, and the presence of genes CEACAM5, BPIFA1, and CK7 in mRNA was studied. The significant association between the presence of micrometastasis, clinicopathologic characteristics, and patients' outcome was assessed.

RESULTS

Eighty-nine stage I-II non-small cell lung cancer patients were included in the study. Of the 89 analyzed sentinel lymph nodes, 44 (49.4%) were positive for CK7, 24 (26.9%) for CEACAM5, and 17 (19.1%) for BPIFA1, whereas 10 (11.2%) were positive for the 3 analyzed genes. A survival analysis showed no significant relation between the presence of molecular micrometastasis in the sentinel node and patients' progression.

CONCLUSIONS

The molecular analysis of the sentinel node in patients with early-stage lung cancer shows node affectation in cases staged as stage I/II by hematoxylin-eosin or an immunohistochemical analysis. However, this nodal affectation was not apparently related to patients' outcome.

Long-term outcomes after near-infrared sentinel lymph node mapping in non-small cell lung cancer

OBJECTIVE

To report the first analysis of long-term outcomes using near-infrared (NIR) image-guided sentinel lymph node (SLN) mapping in non-small cell lung cancer (NSCLC).

METHODS

Retrospective analysis of patients with NSCLC enrolled in 2 prospective phase 1 NIR-guided SLN mapping trials, including an indocyanine green (ICG) dose-escalation trial, was performed. All patients underwent NIR imaging for SLN identification followed by multistation mediastinal lymph node sampling (MLNS) and pathologic assessment. Disease-free (DFS) and overall survival (OS) were compared between patients with NIR⁺ SLN (SLN group) and those without (non-SLN group).

RESULTS

SLN detection, recurrence, DFS, and OS were assessed in 42 patients with NSCLC who underwent intraoperative peritumoral ICG injection, NIR imaging, and MLNS. NIR⁺ SLNs were identified in 23 patients (SLN group), whereas SLNs were not identified in 19 patients enrolled before ICG dose and camera optimization (non-SLN group). Median follow-up was 44.5 months. Pathology from NIR⁺ SLNs was concordant with overall nodal status in all 23 patients. Sixteen patients with SLN were deemed pN0 and no recurrences were, whereas 4 of 15 pN0 non-SLN patients developed nodal or distant recurrent disease. Comparing SLN versus non-SLN pN0 patients, the probability of 5-year OS is 100% versus 70.0% (P = .062) and 5-year DFS is statistically significantly improved at 100% versus 66.1% (P = .036), respectively. Among the 11 pN+ patients, 7 were in the SLN group, with >40% showing metastases in the SLN alone.

CONCLUSIONS

Patients with pN0 SLNs showed favorable disease-free and overall survival. This preliminary review of NIR SLN mapping in NSCLC suggests that pN0 SLNs may better represent true N0 status. A larger clinical trial is planned to validate these findings.

Sentinel lymph node mapping in gynecological oncology

The intraoperative mapping of sentinel lymph nodes (SLNs) is part of the treatment strategy for a number of types of tumor. To retrospectively compare results from the mapping of pelvic SLNs for gynecological oncology, using distinct dyes, the present review was conducted to determine the clinical significance of SLN mapping for gynecological oncology. In addition, the present study aimed at identifying an improved choice for SLN mapping tracers in clinical application. Each dye exhibits demerits when applied in the clinical environment. The combination of radioisotopes and blue dyes was identified to exhibit the most accurate detection rate of SLN drainage of gynecological oncology. However, contrast agents were unable to identify whether a SLN is positive or negative for metastasis prior to pathologic examination; additional studies are required.

Biopsy of the sentinel node in lung cancer

INTRODUCTION AND OBJECTIVE

Mediastinal lymph node involvement can be understaged in cases of lung cancer (up to 20% in stage i). Sentinel node detection is a standard technique recommended in breast cancer and melanoma action guidelines, and could also be useful in cases of lung cancer.

MATERIAL AND METHODS

Considering the detection of the sentinel node in non-small cell lung cancer (NSCLC) as feasible, a prospective cohort study was carried out on 48 patients with resectable NSCLC, using the intraoperative injection of colloid sulphate technetium-99.

RESULTS

The radioisotope migrated in all cases. The procedure's sensitivity was 88.24%, its accuracy was 95.83%, its negative predictive value was 93.94% and the false negative rate was 11.76%. No complications were associated with this technique.

CONCLUSIONS

The detection of a sentinel node in NSCLC with the intraoperative injection of the isotope is feasible and safe, and allows for detection and sensitivity rates comparable to those of other tumour types.

A novel technique for tumor localization and targeted lymphatic mapping in early-stage lung cancer

OBJECTIVE

To investigate safety and feasibility of navigational bronchoscopy (NB)-guided near-infrared (NIR) localization of small, ill-defined lung lesions and sentinel lymph nodes (SLN) for accurate staging in patients with non-small cell lung cancer (NSCLC).

METHODS

Patients with known or suspected stage I NSCLC were enrolled in a prospective pilot trial for lesion localization and SLN mapping via NB-guided NIR marking. Successful localization, SLN detection rates, histopathologic status of SLN versus overall nodes, and concordance to initial clinical stage were measured. Ex vivo confirmation of NIR⁺ SLNs and adverse events were recorded.

RESULTS

Twelve patients underwent NB-guided marking with indocyanine green of lung lesions ranging in size from 0.4 to 2.2 cm and located 0.1 to 3 cm from the pleural surface. An NIR⁺ "tattoo" was identified in all cases. Ten patients were diagnosed with NSCLC and 9 SLNs were identified in 8 of the 10 patients, resulting in an 80% SLN detection rate. SLN pathologic status was 100% sensitive and specific for overall nodal status with no false-negative results. Despite previous nodal sampling, one patient was found to have metastatic disease in the SLN alone, a 12.5% rate of disease upstaging with NIR SLN mapping. SLN were detectable for up to 3 hours, allowing time for obtaining a tissue diagnosis and surgical resection. There were no adverse events associated with NB-labeling or indocyanine green dye itself.

CONCLUSIONS

NB-guided NIR lesion localization and SLN identification was safe and feasible. This minimally invasive image-guided technique may permit the accurate localization and nodal staging of early stage lung cancers.

Immunohistochemical Study of Sentinel Lymph Node in Colon Cancer

Identification of sentinel lymph node (SLN) in colon cancer is very important in order to increase the accuracy of lymph node staging. The number of examined lymph nodes represents a significant predictor of survival. This study aims to show the importance of SLN histological and immunohistochemical examination in adjuvant oncological treatment. The study includes 23 patients with colon cancer (44% women and 56% men) who came in our clinic for surgical intervention. In all cases, the SLN was identified and prepared for histological examination. In 13 of the cases, micrometastases were found onhaematoxylin-eosin (HE) staining, there were 5 cases with positive immunohistochemistry using antibodies anti-p53, anti-VEGF-C, anti-CD34, and 5 cases with SLN negative both for HE and immunohistochemistry. Altogether we had a detection rate of 92%, an accuracy of 78,2%, a sensitivity of 90%, a false negative rate of 10% and a negative predictive value of 71,4%, good values according to the literature. Four (17,3%) patients had micrometastases exclusively in the sentinel lymph node, after performing additional histological examination, using multilevel section and immunohistochemistry. After assessing the SNL on our patients, we concluded that it is a reproducible practice for lymph node analysis.

From Diagnosis to Treatment: Clinical Applications of Nanotechnology in Thoracic Surgery

Nanotechnology is an emerging field with potential as an adjunct to cancer therapy, particularly thoracic surgery. Therapy can be delivered to tumors in a more targeted fashion, with less systemic toxicity. Nanoparticles may aid in diagnosis, preoperative characterization, and intraoperative localization of thoracic tumors and their lymphatics. Focused research into nanotechnology's ability to deliver both diagnostics and therapeutics has led to the development of nanotheranostics, which promises to improve the treatment of thoracic malignancies through enhanced tumor targeting, controlled drug delivery, and therapeutic monitoring. This article reviews nanoplatforms, their unique properties, and the potential for clinical application in thoracic surgery.

The inextricable axis of targeted diagnostic imaging and therapy: An immunological natural history approach

In considering the challenges of approaches to clinical imaging, we are faced with choices that sometimes are impacted by rather dogmatic notions about what is a better or worse technology to achieve the most useful diagnostic image for the patient. For example, is PET or SPECT most useful in imaging any particular disease dissemination? The dictatorial approach would be to choose PET, all other matters being equal. But is such a totalitarian attitude toward imaging selection still valid? In the face of new receptor targeted SPECT agents one must consider the remarkable specificity and sensitivity of these agents. (99m)Tc-Tilmanocept is one of the newest of these agents, now approved for guiding sentinel node biopsy (SLNB) in several solid tumors. Tilmanocept has a Kd of 3×10(-11)M, and it specificity for the CD206 receptor is unlike any other agent to date. This coupled with a number of facts, that specific disease-associated macrophages express this receptor (100 to 150 thousand receptors), that the receptor has multiple binding sites for tilmanocept (>2 sites per receptor) and that these receptors are recycled every 15 min to bind more tilmanocept (acting as intracellular "drug compilers" of tilmanocept into non-degraded vesicles), gives serious pause as to how we select our approaches to diagnostic imaging. Clinically, the size of SLNs varies greatly, some, anatomically, below the machine resolution of SPECT. Yet, with tilmanocept targeting, the SLNs are highly visible with macrophages stably accruing adequate (99m)Tc-tilmanocept counting statistics, as high target-to-background ratios can compensate for spatial resolution blurring. Importantly, it may be targeted imaging agents per se, again such as tilmanocept, which may significantly shrink any perceived chasm between the imaging technologies and anchor the diagnostic considerations in the targeting and specificity of the agent rather than any lingering dogma about the hardware as the basis for imaging approaches. Beyond the elements of imaging applications of these agents is their evolution to therapeutic agents as well, and even in the neo-logical realm of theranostics. Characteristics of agents such as tilmanocept that exploit the natural history of diseases with remarkably high specificity are the expectations for the future of patient- and disease-centered diagnosis and therapy.

Nanotechnology applications in thoracic surgery

Nanotechnology is an emerging, rapidly evolving field with the potential to significantly impact care across the full spectrum of cancer therapy. Of note, several recent nanotechnological advances show particular promise to improve outcomes for thoracic surgical patients. A variety of nanotechnologies are described that offer possible solutions to existing challenges encountered in the detection, diagnosis and treatment of lung cancer. Nanotechnology-based imaging platforms have the ability to improve the surgical care of patients with thoracic malignancies through technological advances in intraoperative tumour localization, lymph node mapping and accuracy of tumour resection. Moreover, nanotechnology is poised to revolutionize adjuvant lung cancer therapy. Common chemotherapeutic drugs, such as paclitaxel, docetaxel and doxorubicin, are being formulated using various nanotechnologies to improve drug delivery, whereas nanoparticle (NP)-based imaging technologies can monitor the tumour microenvironment and facilitate molecularly targeted lung cancer therapy. Although early nanotechnology-based delivery systems show promise, the next frontier in lung cancer therapy is the development of 'theranostic' multifunctional NPs capable of integrating diagnosis, drug monitoring, tumour targeting and controlled drug release into various unifying platforms. This article provides an overview of key existing and emerging nanotechnology platforms that may find clinical application in thoracic surgery in the near future.

Validation of survival prognostic models for non-small-cell lung cancer in stage- and age-specific groups

PURPOSE

Prognostic models have been proposed to predict survival for non-small-cell lung cancer (NSCLC). It is important to evaluate whether these models perform better than performance status (PS) alone in stage- and age-specific subgroups.

PATIENTS AND METHODS

The validation cohort included 2060 stage I and 1611 stage IV NSCLC patients from 23CALGB studies. For stage I, Blanchon (B), Chansky (C) and Gail (G) models were evaluated along with the PS only model. For stage IV, Blanchon (B) and Mandrekar (M) models were compared with the PS only model. The c-index was used to assess the concordance between survival and risk scores. The c-index difference (c-difference) and the integrated discrimination improvement (IDI) were used to determine the improvement of these models over the PS only model.

RESULTS

For stage I, B and PS have better survival separation. The c-index for B, PS, C and G are 0.61, 0.58, 0.57 and 0.52, respectively, and B performs significantly better than PS with c-difference=0.034. For stage IV, B, M and PS have c-index 0.61, 0.64 and 0.60, respectively; B and M perform significantly better than PS with c-difference=0.015 and 0.033, respectively.

CONCLUSION

Although some prognostic models have better concordance with survival than the PS only model, the absolute improvement is small. More accurate prognostic models should be developed; the inclusion of tumor genetic variants may improve prognostic models.

Minimally invasive electro-magnetic navigational bronchoscopy-integrated near-infrared-guided sentinel lymph node mapping in the porcine lung

Background

The use of near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) for sentinel lymph node (SN) mapping has been investigated in lung cancer; however, this has not been fully adapted for minimally invasive surgery (MIS). The aim of our study was to develop a minimally invasive SN mapping integrating pre-operative electro-magnetic navigational bronchoscopy (ENB)-guided transbronchial ICG injection and intraoperative NIR thoracoscopic imaging.

Methods

A NIR thoracoscope was used to visualize ICG fluorescence. ICG solutions in a 96-well plate and ex vivo porcine lungs were examined to optimize ICG concentrations and injection volumes. Transbronchial ICG injection (n=4) was assessed in comparison to a traditional transpleural approach (n=3), where after thoracotomy an ICG solution (100μL at 100μg/mL) was injected into the porcine right upper lobe for SN identification. For further translation into clinical use, transbronchial ICG injection prior to thoracotomy followed by NIR thoracoscopic imaging was validated (n=3). ENB was used for accurate targeting in two pigs with a pseudo-tumor.

Results

The ICG fluorescence at 10 μg/mL was the brightest among various concentrations, unchanged by the distance between the thoracoscope and ICG solutions. Injected ICG of no more than 500μL showed a localized fluorescence area. All 7 pigs showed a bright paratracheal lymph node within 15 minutes post-injection, with persistent fluorescence for 60 minutes. The antecedent transbronchial ICG injection succeeded in SN identification in all 3 cases at the first thoracoscopic inspection within 20 minutes post-injection. The ENB system allowed accurate ICG injection surrounding the pseudo-tumors.

Conclusions

ENB-guided ICG injection followed by NIR thoracoscopy was technically feasible for SN mapping in the porcine lung. This promising platform may be translated into human clinical trials and is suited for MIS.

Current innovations in sentinel lymph node mapping for the staging and treatment of resectable lung cancer

Despite surgical resectability, early-stage lung cancer remains a challenge to cure. Survival outcomes are hindered by variable performance of adequate lymphadenectomy and the limitations of current pathologic nodal staging. Sentinel lymph node (SLN) mapping, a mainstay in the management of breast cancer and melanoma, permits targeted nodal sampling for efficient and accurate staging that can influence both intraoperative and adjuvant treatment decisions. Unfortunately, standard SLN identification techniques with blue dye and radiocolloid tracers have not been shown to be reproducible in lung cancer. In more recent years, intraoperative near-infrared image-guided lung SLN mapping has emerged as promising technology for the identification of the tumor-associated lymph nodes most likely to contain metastatic disease. Additionally, the clinical relevance of SLN mapping for lung cancer remains pressing, as the ability to identify micrometastatic disease in SLNs could facilitate trials to assess chemotherapeutic response and the clinical effect of occult nodal disease. This review outlines the status of lung cancer lymphatic mapping and techniques in development that may help close the gap between translational research in this field and routine clinical practice.

Micrometastatic cancer cells in lymph nodes, bone marrow, and blood: Clinical significance and biologic implications

Cancer metastasis may be regarded as a progressive process from its inception in the primary tumor microenvironment to distant sites by way of the lymphovascular system. Although this type of tumor dissemination often occurs in an orderly fashion via the sentinel lymph node (SLN), acting as a possible gateway to the regional lymph nodes, bone marrow, and peripheral blood and ultimately to distant metastatic sites, this is not a general rule as tumor cells may enter the blood and spread to distant sites, bypassing the SLN. Methods of detecting micrometastatic cancer cells in the SLN, bone marrow, and peripheral blood of patients have been established. Patients with cancer cells in their SLN, bone marrow, or peripheral blood have worse clinical outcomes than patients with no evidence of spread to these compartments. The presence of these cells also has important biologic implications for disease progression and the clinician's understanding of the process of cancer metastasis. Further characterization of these micrometastatic cancer cells at each stage and site of metastasis is needed to design novel selective therapies for a more "personalized" treatment.

Lymphoscintigraphy in early-stage non-small cell lung cancer with technetium-99m nanocolloids and hybrid SPECT/CT: a pilot project

OBJECTIVE

The goal of our study was to determine if lymph node activity could be visualized using a hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) scanner with two commonly used colloidal lymphatic radiotracers--99mTc-antimony sulfide colloid (ASC) and 99mTc-filtered sulfur colloid (FSC) in the setting of low-stage non-small cell lung cancer (NSCLC).

METHODS

Patients undergoing CT-guided percutaneous lung biopsies for clinically suspected early-stage lung cancer were randomized to peri-lesional injection of 37 MBq (0.5 mL) of either ASC or FSC. SPECT/CT of the thorax was performed at either 1, 2, or 3 h post-injection. The images were reviewed to determine if lymph node activity separate from the injection site could be identified.

RESULTS

24 patients were included. Lymph node activity was identified in 50% of patients. A total of 15 lymph nodes with activity were visualized including 5 ipsilateral hilar, 6 ipsilateral mediastinal, and 4 distant locations. No contralateral mediastinal or hilar activity was visualized. There was a tendency to improved visualization with ASC and the longer 3 h wait time. Most patients also demonstrated significant pleural, tracheobronchial, and/or systemic activity.

CONCLUSIONS

SPECT/CT imaging can demonstrate lymph node activity separate from the injection site in at least some low-stage NSCLC patients with a perilesional injection of 99mTc nanocolloid tracers. Further investigation into the role of pre-operative lymphoscintigraphy with SPECT/CT in patients with lung cancer is warranted.

Improved staging using intraoperative ultrasound for mediastinal lymphadenectomy in non-small lung cancer surgery

BACKGROUND

Extent of lymph node involvement in patients with non-small cell lung cancer (NSCLC) is the cornerstone of staging and influences both multimodality treatment and final outcome. The aim of this study was to investigate accuracy and characteristics of intraoperative ultrasound guided systematic mediastinal nodal dissection in patients with resected NSCLC.

METHODS

From January 2008 to June 2013, 244 patients undergoing intraoperative surgical staging after radical surgery for NSCLC were included in prospective study. The patients were divided in two groups according to systematic mediastinal nodal dissection: 124 patients in intraoperative ultrasound nodal dissection guided group and 120 in standard nodal dissection group. The lymph nodes were mapped by their number and station and histopathologic evaluation was performed.

RESULTS

Operating time was prolonged for 10 min in patients with ultrasound guided mediastinal nodal dissection, but number and stations of evaluated lymph nodes were significantly higher (p < 0.001) in the same group. Skip nodal metastases were found in 24% of patients without N1 nodal involvement. Twelve (10%) patients were upstaged using US guided mediastinal lymphadenectomy. In US guided group 5-year survival rate was 59% and in the group of standard systematic mediastinal lymphadenectomy 43% (p = 0.001) Standard staging system seemed to be improved in ultrasound guided mediastinal lymphadenectomy patients. Complication rate showed no difference between analyzed groups.

CONCLUSION

Higher number and location of analyzed mediastinal nodal stations in patients with resected NSCLC using ultrasound is suggested to be of great oncological significance. Our results indicate that intraoperative ultrasound may have important staging implications.

Thoracoscopic color and fluorescence imaging system for sentinel lymph node mapping in porcine lung using indocyanine green-neomannosyl human serum albumin: intraoperative image-guided sentinel nodes navigation

PURPOSE

This study was performed to validate a newly developed sentinel lymph node (SLN) targeting tracer, indocyanine green-neomannosyl human serum albumin (ICG:MSA), and a thoracoscopic version of the intraoperative color and fluorescence imaging system (ICFIS) for lung cancer SLN mapping.

METHODS

ICG alone or ICG:MSA (5 μg/kg) was injected into the rat thigh, and the results were compared. The fluorescence signal-to-background ratios of SLNs were recorded and evaluated over a 2-h period by using ICFIS. Additionally, a SLN biopsy was performed via video-assisted thoracoscopic surgery with the use of ICG:MSA in porcine lung by using thoracoscopic ICFIS.

RESULTS

The newly developed ICG:MSA showed a significantly improved signal-to-background ratio compared with ICG alone throughout the trials. All SLNs were identified in both rats (ten SLNs in ten rat thighs) and pigs (ten SLNs in ten porcine lungs) under in vivo conditions. All SLNs were dissected successfully by using video-assisted thoracoscopic surgery with the help of thoracoscopic ICFIS.

DISCUSSION

ICG:MSA accumulates in the SLN by uptake and retention through the mannose-specific receptors on macrophages. Thoracoscopic ICFIS successfully assisted SLN mapping despite low near-infrared light transmission in the commercial thoracoscope. On the basis of the results of the thoracoscopic SLN mapping, we anticipate that ICG:MSA and thoracoscopic ICFIS can be translated to clinical trials in the near future.

The stage classification of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

The current Lung Cancer Stage Classification system is the seventh edition, which took effect in January 2010. This article reviews the definitions for the TNM descriptors and the stage grouping in this system.

Identification of metastatic nodal disease in a phase 1 dose-escalation trial of intraoperative sentinel lymph node mapping in non-small cell lung cancer using near-infrared imaging

OBJECTIVES

Early-stage non-small cell lung cancer (NSCLC) has a high recurrence rate and poor 5-year survival, particularly if lymph nodes are involved. Our objective was to perform a dose-escalation study to assess safety and feasibility of intraoperative near-infrared (NIR) fluorescence imaging to identify the first tumor-draining lymph nodes (ie, sentinel lymph nodes [SLNs] in patients with NSCLC).

METHODS

A-dose escalation phase 1 clinical trial assessing real-time NIR imaging after peritumoral injection of 3.8 to 2500 μg indocyanine green (ICG) was initiated in patients with suspected stage I/II NSCLC. Visualization of lymphatic migration, SLN identification, and adverse events were recorded.

RESULTS

Thirty-eight patients underwent ICG injection and NIR imaging via thoracotomy (n = 18) or thoracoscopic imaging (n = 20). SLN identification increased with ICG dose, with fewer than 25% SLNs detected in dose cohorts of 600 μg or less versus 89% success at 1000 μg or greater. Twenty-six NIR(+) SLNs were identified in 15 patients, with 7 NIR(+) SLNs (6 patients) harboring metastatic disease on histologic analysis. Metastatic nodal disease was never identified in patients with a histologically negative NIR(+) SLN. No adverse reactions were noted.

CONCLUSIONS

NIR-guided SLN identification with ICG was safe and feasible in this initial dose-escalation trial. ICG doses greater than 1000 μg yielded nearly 90% intrathoracic SLN visualization, with the presence or absence of metastatic disease in the SLN directly correlating with final nodal status of the lymphadenectomy specimen. Further studies are needed to optimize imaging parameters and confirm sensitivity and specificity of SLN mapping in NSCLC using this promising imaging technique.

Intraoperative nodal staging: role of sentinel node technology

In cases of superficial malignancies such as melanoma or breast cancer, intraoperative lymph node mapping with a sentinel lymph node (SLN) biopsy is an effective and minimally invasive alternative to inguinal or axillary lymph node dissection for early-stage tumors. For primary lung cancer, although much effort has been made to investigate a variety of tracers, such as dyes, radioisotopes, magnetite, and iopamidol, for discerning SLNs, an appropriate agent that produces high identification and accuracy rates has yet to be developed. Further studies are needed to find an ideal tracer for practical use in patients with non-small cell lung cancer.

Intraoperative combined color and fluorescent images-based sentinel node mapping in the porcine lung: comparison of indocyanine green with or without albumin premixing

OBJECTIVES

We developed a multimodal optical imaging system for intraoperative visualization of sentinel lymph nodes (SLNs). This study is to validate our system by showing SLNs in the lung through combined optical color and fluorescent image with indocyanine green (ICG) and ICG with human serum albumin (HSA).

METHODS

Identical ICG concentrations of ICG only or ICG:HSA was injected into the rat footpad and porcine lung. Absolute amounts of the fluorescents were scaled on the basis of animal weights. The entire procedures were recorded using color and near-infrared (NIR) charge-coupled device (CCD) cameras simultaneously, and the 2 images were merged by real-time image processing software. All fluorescence intensity signals to background ratio (SBR) and retention rates at SLN for both fluorescents were estimated and compared.

RESULTS

This newly developed intraoperative color and fluorescence optical imaging system successfully visualized the SLNs in animal experiments. The SLNs were identified 100% for both rat and pig under in vivo conditions. Real-time image processing software overcame the low signal of NIR fluorescence images. ICG and ICG:HSA provided no significantly different SBR in the SLN images for both rat thigh and pig lung.

CONCLUSIONS

The intraoperative optical imaging system enabled real-time image-guided surgery during SLN mapping in lung in an animal model. The ICG retention rate was similar to ICG:HSA. ICG alone can be useful for SLN imaging during lung cancer surgery.

Accuracy of sentinel node biopsy in the staging of non-small cell lung carcinomas: systematic review and meta-analysis of the literature

BACKGROUND

Not all patients with non-small cell lung carcinoma (NSCLC) have mediastinal lymph node involvement and development of less invasive methods for evaluating mediastinal lymph nodes is important. Sentinel node biopsy has been used for NSCLC since 1999 to decrease the need for mediastinal lymph node dissection. In this review, we searched the literature in this regard and reported the results in a meta-analysis format.

METHODS

Medline, SCOPUS, and ISI web of knowledge were searched using: "(lung AND sentinel)" with no date or language limit. Any study with more than 5 patients and enough information to calculate detection rate and sensitivity was included.

RESULTS

Overall 47 and 43 studies (including subgroups) had the criteria for detection rate and sensitivity pooling respectively. Pooled detection rate was 80.6% [76.8-84%] and pooled sensitivity was 87% [83-90%]. Using radiotracers or both radiotracers and dyes had higher detection rate and sensitivity compared to dye alone. Among studies using radiotracers, highest detection rate was in intra-operative peri-tumoral injection group and highest sensitivity was in peri-tumoral pre-operative injection group. Emerging methods of sentinel node surgery including magnetic materials, fluorescent dyes, CT contrast agents, and carbon nano-particles had promising results.

CONCLUSIONS

Sentinel node mapping using radiotracers is a feasible technique for mediastinal lymph node staging of N0 NSCLC patients. Alternative methods of sentinel node mapping are promising and warrant further studies.

Preclinical study of near-infrared-guided sentinel lymph node mapping of the porcine lung

BACKGROUND

The presence of lymph node metastasis is the most important prognostic factor in early non-small cell lung cancer. Our objective was to develop a rapid, simple, and reliable method for thoracic sentinel lymph node (SLN) identification using near-infrared fluorescence imaging and clinically available contrast agents.

METHODS

Indocyanine green (ICG) reconstituted in saline, human serum albumin, human fresh frozen plasma, and autologous porcine plasma was evaluated for optimal formulation and dosing for SLN within porcine lungs. Animals were imaged using the fluorescence-assisted resection and exploration for surgery imaging system. The SLN identification rate, time to identification and fluorescence intensity of the SLN, bronchus, and background were measured.

RESULTS

The SLN identification rates varied widely, ranging from 33% to 100% as a function of the carrier used for ICG reconstitution. No significant difference was noted in SLN fluorescence intensity; however, bronchial intensity was significantly higher with ICG: albumin, which resulted in the lowest rate of SLN identification. Subsequent evaluation with 125 μM and 250 μM ICG:porcine plasma resulted in identification of strongly fluorescent SLNs, with identification rates of 93% and 100% and median signal-to-background ratios of 8.5 and 12.15, respectively, in less than 2 minutes in situ.

CONCLUSIONS

Near-infrared fluorescence imaging with ICG is a reliable method for SLN mapping in the lung with high sensitivity. Mixing of ICG with plasma resulted in strong SLN fluorescence signal with reliable identification rates.

Developing intrathoracic sentinel lymph node mapping with near-infrared fluorescent imaging in non-small cell lung cancer

With poor survival and high recurrence rates, early-stage lung cancer currently appears to be understaged or undertreated, or both. Although sentinel lymph node biopsy is standard for patients with breast cancer and melanoma, its success has been unreliable in non-small cell lung cancer. Sentinel lymph node biopsy might aid in the identification of lymph nodes at the greatest risk of metastasis and allow for more detailed analysis to select for patients who might benefit from adjuvant therapy. The early results in our recent clinical trial of patients with early-stage lung cancer have suggested that near-infrared imaging might offer a platform for reliable sentinel lymph node identification in these patients.

Sentinel node navigation surgery by thoracoscopic fluorescence imaging system and molecular examination in non-small cell lung cancer

PURPOSE

The application of sentinel node navigation surgery in non-small cell lung cancer (NSCLC) is not popular because of the difficulty of sentinel node identification and the low incidence of complications after systemic lymph node dissection. We report the intraoperative assessment of sentinel node metastasis by thoracoscopic ICG fluorescence imaging system and real-time reverse transcription-polymerase chain reaction (RT-PCR).

METHODS

Sixty-one patients who underwent surgery between January 2009 and December 2010 were investigated for sentinel node biopsy. ICG fluorescence imaging was applied by an infrared light CCD system, and sentinel nodes were identified and dissected. Intraoperative real-time quantitative RT-PCR to determine the expression of cytokeratin 19 (CK-19) was performed for evaluation of metastasis and finally histologic examination of hematoxylin and eosin-stained, paraffin-embedded sections.

RESULTS

Sixteen (80%) of 20 patients with segmentectomy and 33 (80.5%) of 41 with lobectomy were identified for sentinel lymph nodes. The total identification rate was 80.3% (49 of 61). The false-negative rate was 2.1% (1 of 49). The overall accuracy rate was 78.7% (48 of 61 patients). Disease of four of these patients was upstaged to stage IIA by RT-PCR for CK-19 expression, which was positive for sentinel nodes and micrometastases.

CONCLUSIONS

These results demonstrated that thoracoscopic ICG fluorescence imaging-guided surgery and real-time quantitative RT-PCR were useful for sentinel node biopsy and might be a powerful tool for more focused pathologic or molecular evaluation for staging.

Pathologic lymph node staging practice and stage-predicted survival after resection of lung cancer

BACKGROUND

Lymph node status is the most important prognostic factor in resectable nonsmall-cell lung cancer (NSCLC). We examined the relationship between the pattern of lymph node examination (including the number and anatomic location of resected lymph nodes), pathologic nodal stage, and survival after NSCLC resection.

METHODS

Retrospective review of all NSCLC resections in the Memphis Metropolitan Area from January 1, 2004, to December 31, 2007.

RESULTS

In 656 resections, the number of lymph nodes examined differed significantly between patients grouped by pathologic nodal stage (p<0.0001) and extent of resection (p<0.001). Thirty-seven percent of "mediastinal node-negative" patients had no mediastinal lymph nodes examined. Patients with pN1 and no mediastinal lymph node examination had better [corrected] survival than patients with mediastinal lymph node examination (p < 0.02) . Approximately 10% of patients with pN0 and pN2 disease had no hilar/intrapulmonary lymph nodes examined.

CONCLUSIONS

Suboptimal lymph node staging was prevalent in this cohort. Large proportions of pN1 and pN0 patients were probably understaged. In patients with pathologic positive pulmonary/hilar lymph nodes, mediastinal lymph node examination was associated with poorer survival [corrected]. Interventions are needed to improve lymph node staging of NSCLC.

Impact of nodal status and tumor burden in sentinel lymph nodes on the clinical outcomes of cancer patients

The validation of sentinel lymph node (SLN) concept in melanoma and breast cancer has established a new paradigm in cancer metastasis that, in general, cancer cells spread in a orderly fashion from the primary site to the SLNs in the regional nodal basin and then to the distant sites. In this review article, we examine the development of SLN concept in penile carcinoma, melanoma and breast carcinoma and its application to other solid cancers with emphasis of the relationship between micrometastasis in SLNs and clinical outcomes.

Current trends and emerging future of indocyanine green usage in surgery and oncology: a literature review

Ever since Kitai first performed fluorescent navigation of sentinel lymph nodes (SLNs) using indocyanine green (ICG) dye with a charge-couple device and light emitting diodes, the intraoperative use of near infrared fluorescence has served a critical role in increasing our understanding in various fields of surgical oncology. Here the authors review the emerging role of the ICG fluorophore in the development of our comprehension of the lymphatic system and its use in SLN mapping and biopsy in various cancers. In addition, they introduce the novel role of ICG-guided video angiography as a new intraoperative method of assessing microvascular circulation. The authors attempt to discuss the promising potential in addition to assessing several challenges and limitations in the context of specific surgical procedures and ICG as a whole. PubMed and Medline literature databases were searched for ICG use in clinical surgical settings. Despite ICG's significant impact in various fields of surgical oncology, ICG is still in its nascent stages, and more in-depth studies need to be carried out to fully evaluate its potential and limitations.

Therapeutic sentinel lymph node imaging

Improving existing means of sentinel lymph node identification in non-small cell lung cancer will allow for molecular detection of occult micrometastases that may cause recurrence in early stage non-small cell lung cancer. Furthermore, targeted application of chemical and biological cytotoxic agents can potentially improve outcomes in patients with lymph node (LN) metastases. "Therapeutic Sentinel Lymph Node Imaging" incorporates these modalities into a single agent thereby identifying which LNs harbor tumor cells and simultaneously eradicating metastatic disease. In this review, we summarize the novel preclinical agents for identification and treatment of tumor bearing LNs and discuss their potential for clinical translation.

Sentinel node mapping in lung cancer: the Japanese experience

The reduction in lymph node dissection using sentinel node (SN) identification in patients with lung cancer is associated with several difficulties, compared with similar procedures in patients with breast cancer or melanoma. To overcome the difficulties of SN identification in lung cancer, several topics have been reported in Japan. In this study, the following topics regarding SN identification in lung cancer patients will be introduced: (1) devices for SN identification using a radioisotope tracer; (2) movement of Tc-99 tin colloid after injection; (3) characteristics of patients in whom SNs could not be identified; (4) results of ex vivo SN identification; (5) reliability of in vivo SN identification; (6) algorithm for reducing mediastinal lymph node dissection; (7) SN identification using SPECT/CT; (8) differences in SN identification between large and small radioisotope particles; (9) size of metastatic and nonmetastatic mediastinal lymph nodes in non-small cell lung cancer; (10) SN navigation segmentectomy for clinical stage IA non-small cell lung cancer; and (11) lymphatic flow at segmental lymph nodes.

Image-guided sentinel lymph node mapping and nanotechnology-based nodal treatment in lung cancer using invisible near-infrared fluorescent light

Current methods for sentinel lymph node (SLN) mapping and nodal treatment in lung cancer remain inadequate for routine clinical use. In this study, we discuss the potential for using the combination of invisible near-infrared (NIR) fluorescent light and nanotechnology for these applications. NIR fluorescence imaging has recently received significant attention for in vivo imaging applications because of its low tissue autofluorescence, high photon penetration into living tissue, and high signal-to-background ratio. Our large animal in vivo studies have been able to successfully identify SLNs in lung tissue, and several clinical studies have examined the use of NIR fluorescence imaging systems for SLN mapping in breast and gastric cancer. Promising new nanoparticle technologies, when combined with NIR fluorescence imaging, offer the potential for image-guided treatment of lymph nodes at high risk for tumor recurrence. This review provides a theoretic and empiric framework for developing the next generation of diagnostic and therapeutic agents for lung cancer.

Sentinel node and positron emission tomography mapping in lung cancer

Radioguided lymph node mapping can potentially improve staging in locoregional non-small cell lung cancer. This is accomplished by using advanced pathologic techniques to detect micrometastases in selected thoracic lymph nodes. The use of isosulfan blue, technetium-99m and (18)F-fluorodeoxyglucose (FDG) as mapping agents have been reported. Despite several limitations in this technique, it may facilitate the selection of patients for novel therapies, resulting in improved outcomes for lung cancer patients.