Sentinel lymph node mapping in lung cancer: a step forward?

Ex-vivo exploration of an endobronchial sentinel lymph node procedure in lung cancer for optimizing workflow and evaluating feasibility of novel imaging tools

Background

Early-stage lung cancer is treated with curative intent by surgery or radiotherapy. However, upstaging is frequently seen after surgery in clinical N0 lung cancer patients, and despite curative intent, 2-year recurrence rates of 9-28% are reported. A sentinel lymph node (SLN) procedure could improve the staging accuracy. We explored the feasibility of performing a navigation bronchoscopy based SLN procedure in human ex-vivo lung cancer specimens to optimize procedural parameters and assess a novel injection tool.

Methods

Ten lung resection specimens were included and allocated to either peri- or intratumoral injection of a tracer combining ^99mTc-nanocolloid and indocyanine green (ICG) while varying the injection volume. A Pioneer Plus catheter with a pre-angulated 24G needle and an ultrasound (US)-element was used to perform real-time US guided transbronchial injections at multiple locations. Thereafter, single photon emission computed tomography/computed tomography (SPECT/CT)-scanning was performed to image injection depots and to assess their location relative to the tumor.

Results

An average volume of 0.7 mL (range, 0.3-1.2 mL) with an average activity of 89.5 MBq ^99mTc (range, 35.4-188.0 MBq) was injected. Intratumoral injections in non-solid and solid tumors were successful in 100% and 64.3% respectively, while 100% of peritumoral injections in solid tumors were successful. The US-element of the catheter allowed real-time imaging and was able to visualize all tumors and 67.4% of all injections. SPECT/CT-scanning visualized 76.7% of the injection depots.

Conclusions

A navigation bronchoscopy mediated SLN procedure seems technically feasible. The Pioneer Plus is a suitable catheter to place tracer depots at multiple intra-/peri-tumoral sites, while receiving real-time feedback on the needle localization in relation to the tumor. The next step of in-vivo injections will determine if tracer drainage to the SLN can also be detected on pre- and per-operative imaging.

Sentinel Lymph Node in Non-Small Cell Lung Cancer: Assessment of Feasibility and Safety by Near-Infrared Fluorescence Imaging and Clinical Consequences

Occult micrometastases can be missed by routine pathological analysis. Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging can identify the first lymph node relay. This sentinel lymph node (SLN) can be analyzed by immunohistochemistry (IHC), which may increase micrometastasis detection and improve staging. This study analyzed the feasibility and safety of identifying SLNs in thoracic surgery by NIR fluorescence imaging in non-small cell lung cancer (NSCLC). This was a prospective, observational, single-center study. Eighty adult patients with suspected localized stage NSCLC (IA1 to IIA) were included between December 2020 and May 2022. All patients received an intraoperative injection of indocyanine green (ICG) directly in the peri tumoural area or by electromagnetic navigational bronchoscopy (ENB). The SLN was then assessed using an infrared fluorescence camera. SLN was identified in 60 patients (75%). Among them, 36 SLNs associated with a primary lung tumor were analyzed by IHC. Four of them were invaded by micrometastases (11.1%). In the case of pN0 SLN, the rest of the lymphadenectomy was cancer free. The identification of SLNs in thoracic surgery by NIR fluorescence imaging seems to be a feasible technique for improving pathological staging.

Immune-Omics Networks of CD27, PD1, and PDL1 in Non-Small Cell Lung Cancer

To date, there are no prognostic/predictive biomarkers to select chemotherapy, immunotherapy, and radiotherapy in individual non-small cell lung cancer (NSCLC) patients. Major immune-checkpoint inhibitors (ICIs) have more DNA copy number variations (CNV) than mutations in The Cancer Genome Atlas (TCGA) NSCLC tumors. Nevertheless, CNV-mediated dysregulated gene expression in NSCLC is not well understood. Integrated CNV and transcriptional profiles in NSCLC tumors (n = 371) were analyzed using Boolean implication networks for the identification of a multi-omics CD27, PD1, and PDL1 network, containing novel prognostic genes and proliferation genes. A 5-gene (EIF2AK3, F2RL3, FOSL1, SLC25A26, and SPP1) prognostic model was developed and validated for patient stratification (p < 0.02, Kaplan-Meier analyses) in NSCLC tumors (n = 1163). A total of 13 genes (COPA, CSE1L, EIF2B3, LSM3, MCM5, PMPCB, POLR1B, POLR2F, PSMC3, PSMD11, RPL32, RPS18, and SNRPE) had a significant impact on proliferation in 100% of the NSCLC cell lines in both CRISPR-Cas9 (n = 78) and RNA interference (RNAi) assays (n = 92). Multiple identified genes were associated with chemoresponse and radiotherapy response in NSCLC cell lines (n = 117) and patient tumors (n = 966). Repurposing drugs were discovered based on this immune-omics network to improve NSCLC treatment.

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.