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

Radioisotope-Guided Excision of Mediastinal Lymph Nodes in Patients with Non-Small Cell Lung Carcinoma: Feasibility and Clinical Impact

BACKGROUND

Intraoperative localisation of nodal disease in non-small cell lung cancer (NSCLC) can be challenging. Lymph node localisation via radiopharmaceuticals is used in many conditions; we tested the feasibility of this approach in NSCLC.

METHODS

NSCLC patients were prospectively recruited. Intraoperative peri-tumoral injections of [99mTc]Tc-albumin nanocolloids were performed, followed by removing the tumour and locoregional lymph nodes. These were examined ex vivo with a gamma probe and labelled sentinel lymph nodes (SLNs) if they showed any activity or non-sentinel lymph nodes (nSLNs) if they did not. Thereafter, the surgical field was scanned with the probe; any further radioactive lymph node was removed and labelled as "extra" SLNs (eSLNs). All specimens were sent to histology, and metastatic status was recorded.

RESULTS

48 patients were enrolled, and 290 nodal stations were identified: 179 SLNs, 87 nSLNs, and 24 eSLNs. A total of 44 nodal metastases were identified in 22 patients, with 36 of them (82%) located within SLNs. Patients with nSLNs metastases had at least a co-existing positive SLN. No metastases were found in eSLNs.

CONCLUSIONS

The technique shows high sensitivity for intraoperative nodal metastases identification. This information could allow selective lymphadenectomies in low-risk patients or more aggressive approaches in high-risk patients.

Repeat injection following sentinel node nonvisualization on lymphoscintigraphy images can decrease axillary dissection rate in breast cancer patients

AIM

Sentinel node biopsy is considered the standard of care in early-stage breast cancer patients. In the current study, we evaluated the effect of radiotracer reinjection in the case of sentinel node nonvisualization on preoperative lymphoscintigraphy.

MATERIALS AND METHODS

Between March 2017 and March 2020, 1850 early-stage breast cancer patients were referred for sentinel node mapping. All patients received a single injected activity of Tc-99m Phytate intradermally in the periareolar area of the index lesion using an insulin syringe. Lymphoscintigraphy images of the patients were done 1-2 h postinjection. Between March 2017 and September 2017, sentinel node nonvisualization was reported to the surgeon, and for the rest of the study period, the patients received another injected activity of the radiotracer, and immediately, other lymphoscintigraphy images were taken (with the same parameters).

RESULTS

A total of 255 patients entered our study. Fifty-five patients were in group I without any reinjection. The remainder of the patients were in group II. In 155 out of 200 patients of group II, a sentinel node could be visualized following reinjection of the radiotracer. The detection rate was 15 out of 45 and 15 out of 55 in group I and patients without sentinel node visualization even after reinjection, respectively. Axilla was involved in 5 out of 40 (12.5%) patients in group I with intraoperative sentinel node mapping failure. On the other hand, axilla was involved in 27 out of 30 (90%) group II patients with sentinel node nonvisualization.

CONCLUSION

Reinjection of the tracer in cases of no sentinel node visualization in lymphoscintigraphy for breast cancer increases the detection rate of sentinel nodes, and therefore a high number of unnecessary axillary lymph node dissections can be avoided.

Sentinel lymph node mapping in breast cancer patients following neoadjuvant chemotherapy: systematic review and meta-analysis about head to head comparison of cN0 and cN + patients

PURPOSE

The effectiveness of sentinel lymph node (SLN) mapping and biopsy following neoadjuvant chemotherapy (NAC) in axillary lymph node staging of breast cancer (BCa) patients with initial clinical node positive status (cN +) compared to clinical node negative status (cN0) is not yet known. The aim of this meta-analysis was to compare the accuracy of SLN mapping following NAC in cN + and cN0 BCa patients.

METHODS

PubMed and Scopus were comprehensively reviewed to retrieve all the studies that performed SLN mapping/biopsy and standard axillary lymph node dissection on cN0 and cN + BCa patients following NAC. Pooled detection and false negative rates for N0 and N + patients including 95% confidence interval values (95% CI) were evaluated. Odds ratio (OR) and risk difference (RD) of SLN detection failure and false negative results were compared between two groups.

RESULTS

A total of 27 articles were included for SLN detection rate evaluation and 17 for false negative assessment. The OR and RD of detection failure in N + group compared with N0 group following NAC were 2.22 (p = 0.00, 95% CI 1.4-3.4) and 4% (p = 0.00, 95% CI 2-6%), respectively. The OR and RD of false negative rate were 1.6 (p = 0.01, 95% CI 1-2.6) and 8% (p = 0.02, 95% CI 1-14%), respectively.

CONCLUSION

SLN mapping in BCa patients following NAC shows high risk of detection failure and high false negative rate of SLN biopsy in cN + patients. In comparison with cN0 BCa patients, SLN mapping and biopsy after NAC was associated with almost two times higher odds of detection failure and false negative results in cN + patients; therefore, this method should not be recommended in this group of patients.

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.

[Analysis of lymphatic drainage pathways using infrared fluorescence in patients with lung cancer]

OBJECTIVE

To develop a method for analysis of lymphatic drainage pathways from the lobe of the lung affected by non-small cell lung cancer (NSCLC) using infrared fluorescence.

MATERIAL AND METHODS

A study enrolled patients with NSCLC who underwent anatomic resection of the lung with systematic lymph node dissection and preliminary intraoperative peritumoral injection of indocyanine green conjugate with human albumin. Registration of fluorescence in regional lymph nodes (LN) was carried out immediately after excision of specimen using the FLUM-808 instrumental system.

RESULTS

Infrared fluorescence was observed in 117 hilar and mediastinal lymph nodes from 43 patients (2.7 nodes per a patient). Comparison of localization of fluorescent LN with localization of tumor in various lobes established significant variability of lymphatic drainage pathways.

CONCLUSION

The developed method of infrared fluorescent evaluation of lymphatic drainage in patients with NSCLC confirms the necessity of systematic lymph node dissection for adequate staging.

Assessment of non-lobe-specific lymph node metastasis in clinical stage IA non-small cell lung cancer

BACKGROUND

The rationality of selective mediastinal lymph node dissection based on lobe-specific metastasis is still controversial. The correlation of lymph node metastasis in lobe-specific lymphatic drainage regions (LSDRs) and non-LSDRs has not been widely reported. The purpose of this study was to investigate the variables affecting nodal metastasis in non-LSDRs and to further evaluate the rationality of selective lymphadenectomy in clinical stage IA non-small cell lung cancer (NSCLC) patients.

METHODS

The clinicopathological information of 316 patients with clinical stage IA NSCLC who underwent lobectomy with systematic lymph node dissection between June 2014 and June 2018 was retrospectively collected for analysis.

RESULTS

The overall lymph node metastasis rate was 19.3%. For 35 patients with positive LSDR lymph nodes, the non-LSDR lymph node metastasis rate was 31.4%. Only one patient (0.4%) among 281 patients with negative LSDR lymph nodes had nodal spread in non-LSDRs. Univariate analysis identified that solid consistency, worse differentiation, and positive status in LSDRs were unfavorable predictive variables of lymph node metastasis in non-LSDRs. Multivariate analysis showed that nodal metastasis in LSDRs was the only independent predictor of nodal involvement in non-LSDRs (P < 0.001).

CONCLUSION

For patients with clinical stage IA NSCLC, non-LSDR lymph node metastasis mainly depends on the involvement of the LSDR lymph node. Our observations may indicate the potential implications for the reasonable management of lymphadenectomy in stage IA NSCLC patients.

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.

Clinical use of near-infrared fluorescence imaging with indocyanine green in thoracic surgery: a literature review

Invisible near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) has advantage in detecting for certain anatomy. The method is currently used in some types of surgery, such as sentinel lymph node (SLN) mapping, intraoperative solid tumor identification, and organ perfusion assessment. However, the literature of clinical application in thoracic surgery is lacking. This paper presents the advantages, current applications and potential developments of NIR fluorescence imaging with ICG in thoracic surgery.

Lymphatic mapping and sentinel node biopsy in ovarian tumors: a study using intra-operative Tc-99m-Phytate and lymphoscintigraphy imaging

Background

Experience on sentinel node mapping in ovarian tumors is very limited. We evaluated the sentinel node concept in ovarian tumors using intra-operativeTc-99m-Phytate injection and lymphoscintigraphy imaging.

Methods

Thirty-five patients with a pelvic mass due to an ovarian pathology were included in the study. The radiotracer was injected just after laparotomy and before removal of the tumor either beneath the normal cortex (10 patients) or in the utero-ovarian and suspensory ligaments of the ovary just beneath the peritoneum two injections of the radiotracer (25 patients). For malignant masses, the sentinel nodes were identified using a hand held gamma probe. Then standard pelvic and para-aortic lymphadenectomy was performed. In case of benign pathologies or borderline ovarian tumors on frozen section, lymphadenectomy was not performed. The morning after surgery, all patients were sent for lymphoscintigraphy imaging of the abdomen and pelvis.

Results

Sentinel node was identified only in 4 patients of the cortical injection group. At least one sentinel node could be identified in 21 patients of the sub-peritoneal group. Sentinel nodes were identified only in the para-aortic area in 21, pelvic/para-aortic areas in 2, and pelvic only area in 2 patients. Three patients had lymph node involvement and all had involved sentinel nodes (no false negative case).

Conclusion

Sentinel node mapping using intra-operative injection of the radiotracer (in the utero-ovarian and suspensory ligaments of the ovary just beneath the peritoneum) is feasible in ovarian tumors. Technical aspects of this method should be explored in larger multicenter studies in the future.

F-18-FDG-avid lymph node metastasis along preferential lymphatic drainage pathways from the tumor-bearing lung lobe on F-18-FDG PET/CT in patients with non-small-cell lung cancer

OBJECTIVE

F-18-FDG-avid lymph node (LN) metastasis may preferentially occur along the lymphatic drainage pathway (LDP) from the tumor-bearing lobe in patients with non-small cell lung cancer (NSCLC) on FDG PET/CT. This study evaluated whether the identification of metastatic LNs according to LDP-based visual image interpretation can improve LN staging on FDG PET/CT in these patients.

METHODS

FDG PET/CT study was performed in 265 patients with NSCLC. The presence and LN station of metastatic LNs were determined by surgery or the clinical course. In the LDP-based interpretation, FDG-avid LNs, which were located along the preferential LDP from each tumor-bearing lobe and visually more intense in FDG uptake compared with the remaining LNs straying away from the preferential LDP, were diagnosed as metastatic. The result was compared with the quantitative method using a cutoff value of 2.5 for the maximum standardized uptake value.

RESULTS

Of the total 1031 mediastinal and hilar LN stations with FDG-avid LNs in 265 patients, 179 stations in 66 patients were metastatic and the remaining 852 were benign. All the metastatic LN stations except for 2 stations showing skip metastasis were located along the main preferential LDP or another preferential LDP via a direct anatomic pathway from each tumor-bearing lung lobe. The specificity, accuracy, and PPV for identifying metastatic LN stations by LDP-based interpretation were 97.9, 95.7 and 89.5 %, respectively, which were significantly greater compared with those of 92.7, 90.8 and 70.3 % by the SUV-based method (P < 0.001).

CONCLUSIONS

The present study shows that FDG-avid LN metastasis preferentially occurs along the LDP from the tumor-bearing lobe in NSCLC patients. LDP-based visual image interpretation on FDG PET/CT can improve LN staging in these patients.

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.

Intraoperative imaging-guided cancer surgery: from current fluorescence molecular imaging methods to future multi-modality imaging technology

Cancer is a major threat to human health. Diagnosis and treatment using precision medicine is expected to be an effective method for preventing the initiation and progression of cancer. Although anatomical and functional imaging techniques such as radiography, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) have played an important role for accurate preoperative diagnostics, for the most part these techniques cannot be applied intraoperatively. Optical molecular imaging is a promising technique that provides a high degree of sensitivity and specificity in tumor margin detection. Furthermore, existing clinical applications have proven that optical molecular imaging is a powerful intraoperative tool for guiding surgeons performing precision procedures, thus enabling radical resection and improved survival rates. However, detection depth limitation exists in optical molecular imaging methods and further breakthroughs from optical to multi-modality intraoperative imaging methods are needed to develop more extensive and comprehensive intraoperative applications. Here, we review the current intraoperative optical molecular imaging technologies, focusing on contrast agents and surgical navigation systems, and then discuss the future prospects of multi-modality imaging technology for intraoperative imaging-guided cancer surgery.

Staging lymph node metastases from lung cancer in the mediastinum

BACKGROUND

The presence of tumor metastases in the mediastinum is one of the most important elements in determining the optimal treatment strategy in patients with non-small cell lung cancer. This review is aimed at examining the current strategies for investigating lymph node metastases corresponding to an "N2" classification delineated by The International Staging Committee of the International Association for the Study of Lung Cancer (IASLC).

METHODS

Extensive review of the existing scientific literature related to the investigation of mediastinal lymph node metastases was undertaken in order to summarize and report current best practices.

CONCLUSIONS

N2 disease is very heterogeneous requiring multiple modalities for thorough investigation. New research is now focusing on better identifying, defining, and classifying lymph node metastases in the mediastinum. Molecular staging and sub-classifying mediastinal lymph node metastases are being actively researched in order to provide better prognostic value and to optimize treatment strategies. Non-invasive imaging, such as PET/CT and minimally invasive techniques such as endobronchial and endoscopic ultrasound guided biopsy, are now the lead investigative methods in evaluating the mediastinum for metastatic presence.

Lack of supportive evidence for the use of immunohistochemical staining to identify occult regional lymph node metastases in primary lung cancer

Immunohistochemical (IHC) staining for the identification of nodal occult metastases (OM), not detected by routine histological examination, has been proposed for improved staging, prognostication and decision of adjuvant treatment in surgically treated primary lung cancer. In a prospective study, we analysed 178 cases of primary lung cancer stage I-III (N0-N1) for OM by immunostaining lymph node tissue using a broad-spectrum anti-cytokeratin antibody. OM were found in 7 (4 %) of the 178 cases. Using Kaplan-Meier analysis, overall survival was not significantly different between cases with stage I and cases upstaged to stage II because of OM (n = 3), or between cases with stage II and cases upstaged to stage III (n = 4). Likewise, the presence of OM was not significantly correlated with overall survival in univariable or multivariable Cox proportional hazards regression models, also when disregarding OM <0.2 mm in size. Given the low frequency of OM and lack of significant impact on survival in our study, the justification for including IHC staining of lymph nodes in lung cancer in clinical practise does not appear convincing. Moreover, we report several potential pitfalls in the use of broad-spectrum cytokeratin IHC staining for OM detection, for example staining of intra-nodal mesothelial cells.

Added value of blue dye injection in sentinel node biopsy of breast cancer patients: do all patients need blue dye?

BACKGROUND

In the current study, we evaluated the incremental value of blue dye injection in sentinel node mapping of early breast cancer patients. We specially considered the experience of the surgeons and lymphoscintigraphy results in this regard.

METHODS

605 patients with early stage breast cancer were retrospectively evaluated in the study. Patients underwent sentinel node mapping using combined radiotracer and blue dye techniques. Lymphoscintiraphy was also performed for 590 patients. Blue dye, radioisotope, and overall success rates in identifying the sentinel lymph node were evaluated in different patient groups. The benefit of blue dye and radioisotope in identifying the sentinel lymph nodes was also evaluated.

RESULTS

Marginal benefits of both blue dye and isotope for overall sentinel node detection as well as pathologically involved sentinel nodes were statistically higher in inexperienced surgeons and in patients with sentinel node visualization failure. In the patients with sentinel node visualization on lymphoscintigraphy, 6 sentinel nodes were detected by blue dye only. All these six nodes were harvested by inexperienced surgeons. On the other hand 8 sentinel nodes were detected by dye only in the patients with sentinel node non-visualization. All these nodes were harvested by experienced surgeons.

CONCLUSIONS

The use of blue dye should be reserved for inexperienced surgeons during their learning phase and for those patients in whom lymphoscintigraphy failed to show any uptake in the axilla.

Pelvic kidney visualization on the lymphoscintigraphy images of a patient with uterine cervix cancer: importance of the delayed imaging

We reported an unusual visualization of a pelvic kidney on the lymphoscintigraphy images of a patient with uterine cervix cancer, which was mistaken with para-aortic sentinel nodes. Delayed imaging clearly showed the nature of this activity. Our case underscores the importance of delayed pelvic lymphoscintigraphy imaging in the sentinel node mapping of gynecological cancers.