Lobe-specific Lymph Node Dissection in Clinical Stage IA Solid-dominant Non-small-cell Lung Cancer: A Propensity Score Matching Study

Convolutional neural network-based program to predict lymph node metastasis of non-small cell lung cancer using 18F-FDG PET

PURPOSE

To develop a convolutional neural network (CNN)-based program to analyze maximum intensity projection (MIP) images of 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron emission tomography (PET) scans, aimed at predicting lymph node metastasis of non-small cell lung cancer (NSCLC), and to evaluate its effectiveness in providing diagnostic assistance to radiologists.

METHODS

We obtained PET images of NSCLC from public datasets, including those of 435 patients with available N-stage information, which were divided into a training set (n = 304) and a test set (n = 131). We generated 36 maximum intensity projection (MIP) images for each patient. A residual network (ResNet-50)-based CNN was trained using the MIP images of the training set to predict lymph node metastasis. Lymph node metastasis in the test set was predicted by the trained CNN as well as by seven radiologists twice: first without and second with CNN assistance. Diagnostic performance metrics, including accuracy and prediction error (the difference between the truth and the predictions), were calculated, and reading times were recorded.

RESULTS

In the test set, 67 (51%) patients exhibited lymph node metastases and the CNN yielded 0.748 predictive accuracy. With the assistance of the CNN, the prediction error was significantly reduced for six of the seven radiologists although the accuracy did not change significantly. The prediction time was significantly reduced for five of the seven radiologists with the median reduction ratio 38.0%.

CONCLUSION

The CNN-based program could potentially assist radiologists in predicting lymph node metastasis by increasing diagnostic confidence and reducing reading time without affecting diagnostic accuracy, at least in the limited situations using MIP images.

A Shift in Paradigm: Selective Lymph Node Dissection for Minimizing Oversurgery in Early Stage Lung Cancer

Systematic lymph node dissection has been widely accepted and turned into a standard procedure for lung cancer surgery. In recent years, the concept of "minimal invasive surgery (MIS)" has greatly changed the surgical paradigm of lung cancer. Previous studies revealed that excessive dissection of lymph nodes without metastases had uncertain clinical benefit. Meanwhile, it leads to the elevated risk of postoperative complications including chylothorax and laryngeal nerve injury. In addition, dissection of nonmetastatic lymph nodes may disturb systematic immunity, resulting in the secondary effect on primary tumor or latent metastases. The past decades have witnessed the innovative strategies such as lobe-specific lymph node dissection and selective lymph node dissection. On the basis of evolution of lymph node dissection strategy, we discuss the negative effects of excessive nonmetastatic lymph node dissection and summarize the recent advances in the optimized dissection strategies, hoping to provide unique perspectives on the future directions.

Lymph node metastasis in cancer progression: molecular mechanisms, clinical significance and therapeutic interventions

Lymph nodes (LNs) are important hubs for metastatic cell arrest and growth, immune modulation, and secondary dissemination to distant sites through a series of mechanisms, and it has been proved that lymph node metastasis (LNM) is an essential prognostic indicator in many different types of cancer. Therefore, it is important for oncologists to understand the mechanisms of tumor cells to metastasize to LNs, as well as how LNM affects the prognosis and therapy of patients with cancer in order to provide patients with accurate disease assessment and effective treatment strategies. In recent years, with the updates in both basic and clinical studies on LNM and the application of advanced medical technologies, much progress has been made in the understanding of the mechanisms of LNM and the strategies for diagnosis and treatment of LNM. In this review, current knowledge of the anatomical and physiological characteristics of LNs, as well as the molecular mechanisms of LNM, are described. The clinical significance of LNM in different anatomical sites is summarized, including the roles of LNM playing in staging, prognostic prediction, and treatment selection for patients with various types of cancers. And the novel exploration and academic disputes of strategies for recognition, diagnosis, and therapeutic interventions of metastatic LNs are also discussed.

Clinical Benefits of Lobe-Specific Lymph Node Dissection in Surgery for NSCLC: A Systematic Review and Meta-Analysis

Introduction

The impact of lobe-specific lymph node dissection (LS-LND) in surgery for NSCLC remains controversial compared with that of systematic lymph node dissection (S-LND). This study aimed to compare clinical outcomes between the two strategies, including postoperative complications, and to explain the advantages of LS-LND.

Methods

We searched for studies comparing LS-LND and S-LND up to April 14, 2022, using PubMed, EMBASE, and Web of Science. The primary outcomes were overall survival and recurrence-free survival. Secondary outcomes included postoperative complications, such as arrhythmia, chylothorax, and pneumonia. We evaluated the risk of bias and assessed the evidence quality using GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach.

Results

A total of 13 studies, including one randomized controlled trial and 12 retrospective studies with 11,522 patients who underwent curative resections for lung cancer, were included. The results indicated that LS-LND had favorable overall survival (hazard ratio [HR] = 0.80, 95% confidence interval [CI]: 0.73-0.87) but no difference in recurrence-free survival (HR = 0.96, 95% CI: 0.84-1.09) on comparison with S-LND. In terms of postoperative complications, patients undergoing LS-LND had a lower rate of chylothorax (risk ratio [RR] = 0.54, 95% CI: 0.35-0.85) and arrhythmia (RR = 0.74, 95% CI: 0.57-0.97) than patients undergoing S-LND, but the risk of postoperative pneumonia was not different. The overall quality of evidence was low to moderate owing to the risk of bias related to heterogeneous study populations.

Conclusions

Patients undergoing LS-LND had a comparable and favorable long-term prognosis and a lower rate of postoperative complications. Nevertheless, further standardized studies are necessary to improve the quality of evidence.

Long-term survival outcomes after lobe-specific nodal dissection in patients with early non-small-cell lung cancer

OBJECTIVES

We investigated the long-term outcomes of lobe-specific nodal dissection (LSD) and systematic nodal dissection (SND) in patients with non-small-cell lung cancer (NSCLC).

METHODS

Patients with c-stage I and II NSCLC who underwent lobectomy with mediastinal nodal dissection were retrospectively analysed. After propensity score matching, we assessed the overall survival (OS), recurrence-free survival (RFS) and cumulative incidence of death (CID) from primary lung cancer and other diseases.

RESULTS

The median follow-up period was 8.4 years. Among 438 propensity score-matched pairs, OS and RFS were similar between the LSD and SND groups [hazard ratio (HR), 0.979; 95% confidence interval (CI), 0.799-1.199; and HR, 0.912; 95% CI, 0.762-1.092, respectively], but the LSD group showed a better prognosis after 5 years postoperatively. CID from primary lung cancer was similar between the 2 groups (HR, 1.239; 95% CI, 0.940-1.633). However, the CID from other diseases was lower in the LSD group than in the SND group (HR, 0.702; 95% CI, 0.525-0.938). According to c-stage, the LSD group tended towards worse OS and RFS, with higher CID from primary lung cancer than the SND group, in patients with c-stage II.

CONCLUSIONS

LSD provides acceptable long-term survival for patients with early-stage NSCLC. However, LSD may not be suitable for patients with c-stage II NSCLC due to the higher mortality risk from primary lung cancer.

Lobe-specific lymph node dissection in early-stage non-small-cell lung cancer: An overview

Lymph node dissection is a vital part of surgical treatment for early-stage non-small cell lung cancer (NSCLC). Lobectomy with systematic lymph node dissection (SLND) still remains the gold standard surgical treatment for early-stage NSCLC patients. However, an increasing number of studies have demonstrated that lobe-specific lymph node dissection (L-SLND) can be used as an alternative therapy for SLND in carefully selected patients with early-stage NSCLC. However, there are no currently available evidences of review summarizing the role of L-SLDN in treating early-stage NSCLC. Therefore, we performed this literature review by summarizing the existing literatures on the lymph node drainage pattern, definition, scope and role of L-SLND in patients with early-stage NSCLC, aiming to provide evidence for the application of L-SLND in patients with early-stage NSCLC.

A novel nomogram to predict lymph node metastasis in cT1 non-small-cell lung cancer based on PET/CT and peripheral blood cell parameters

BACKGROUND

Accurately evaluating the lymph node status preoperatively is critical in determining the appropriate treatment plan for non-small-cell lung cancer (NSCLC) patients. This study aimed to construct a novel nomogram to predict the probability of lymph node metastasis in clinical T1 stage patients based on non-invasive and easily accessible indicators.

METHODS

From October 2019 to June 2022, the data of 84 consecutive cT1 NSCLC patients who had undergone PET/CT examination within 30 days before surgery were retrospectively collected. Univariate and multivariate logistic regression analyses were performed to identify the risk factors of lymph node metastasis. A nomogram based on these predictors was constructed. The area under the receiver operating characteristic (ROC) curve and the calibration curve was used for assessment. Besides, the model was confirmed by bootstrap resampling.

RESULTS

Four predictors (tumor SUVmax value, lymph node SUVmax value, consolidation tumor ratio and platelet to lymphocyte ratio) were identified and entered into the nomogram. The model indicated certain discrimination, with an area under ROC curve of 0.921(95%CI 0.866-0.977). The calibration curve showed good concordance between the predicted and actual possibility of lymph node metastasis.

CONCLUSIONS

This nomogram was practical and effective in predicting lymph node metastasis for patients with cT1 NSCLC. It could provide treatment recommendations to clinicians.

LobE-Specific lymph node diSsectiON for clinical early-stage non-small cell lung cancer: protocol for a randomised controlled trial (the LESSON trial)

INTRODUCTION

Lung cancer was the most common malignancy and the leading cause of cancer-related death in China or worldwide, and surgery is still the preferred treatment for early-stage non-small cell lung cancer (NSCLC). The pattern of lymph node metastasis was found potentially lobe specific, and thus, lobe-specific lymph node dissection (L-SLND) was proposed to be an alternative to systematic lymph node dissection (SLND) for the treatment of early-stage NSCLC.

METHODS AND ANALYSIS

The LobE-Specific lymph node diSsectiON trial is a single-institutional, randomised, double-blind and parallel controlled trial to investigate the feasibility of L-SLND in clinically diagnosed stage IA1-2 NSCLC with ground-glass opacity components (≥50%). The intraoperative frozen section examination of surgical tissues confirms the histological type of NSCLC. We hypothesise that L-SLND (experimental group) is not inferior to SLND (control group) and intend to include 672 participants for the experimental group and 672 participants for the control group with a follow-up duration of 60 months. The primary outcomes are 5-year disease-free survival and 5-year overall survival. The secondary outcomes are metastatic lymph node ratio, postoperative complication incidence and mortality, duration of operation, duration of anaesthesia (min), the volume of bleeding (mL) and drainage volume. The intention-to-treat analysis would be performed in the trial.

ETHICS AND DISSEMINATION

This trial was approved by the ethics committee on biomedical research, West China Hospital of Sichuan University (2021-332). Informed consent would be obtained from all participants, and dissemination activities would include academic conference presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

This trial was registered in the Chinese Clinical Trial Registry, ChiCTR2100048415.

Lobe-specific nodal dissection with intraoperative frozen section analysis for clinical stage-I non-small cell lung cancer: a validation study by propensity score matching

OBJECTIVE

Lobe-specific nodal dissection (LND) is increasingly used for non-small cell lung cancer (NSCLC) in Japan; however, its treatment validity remains unclarified. Since 2013, LND has been used as a standard procedure for clinical stage-I (c-stage-I) NSCLC at our institution. We aimed to evaluate its validity using intraoperative frozen section analysis (FSA) for c-stage-I NSCLC.

METHODS

The participants comprised patients with NSCLC who underwent LND between 2013 and 2016 (n = 307) or systematic nodal dissection (SND) between 2002 and 2013 (n = 367) for c-stage-I disease. FSA was routinely performed in LND to examine at least three stations. Outcomes were compared between the LND and SND groups. Patients in whom LND was converted to SND due to metastasis on FSA of the sampled lymph node were still categorized into the LND group, i.e., intention-to-treat analysis. The prognostic impact was compared using propensity score matching.

RESULTS

The rate of conversion from LND to SND was 10.4%. Of the patients converted to SND, 12.5% had metastases outside the LND area. False-negative N2 results were detected in only 0.7% of the LND group patients after FSA. After matching, each group had 220 patients. There were no significant between-group differences in the lymph-node recurrence rate (7% vs. 6%), 5-year recurrence-free survival (80.1% vs. 79.0%), and overall survival (90.4% vs. 90.3%).

CONCLUSIONS

LND with intraoperative FSA is a valid modality that could serve as a standard surgical procedure for c-stage-I NSCLC. Intraoperative FSA may lower the residual lymph-node metastasis risk in LND.

Permissible Outcomes of Lobe-Specific Lymph Node Dissection for Elevated Carcinoembryonic Antigen in Non-Small Cell Lung Cancer

Background and Objectives: Lobe-specific nodal dissection (L-SND) is currently acceptable for the dissection of early-stage non-small cell lung cancer (NSCLC) but not for cancers of more advanced clinical stages. We aimed to assess the efficacy of L-SND, compared to systemic nodal dissection (SND). Materials and Methods: We retrospectively collected the clinical data of patients with carcinoembryonic antigen (CEA) abnormality who underwent complete resection of NSCLC via lobectomy or more in addition to either SND or L-SND at two cancer-specific institutions from January 2006 to December 2017. Results: A total of 799 patients, including 265 patients who underwent SND and 534 patients who underwent L-SND, were included. On multivariate analysis, thoracotomy, more than lobectomy, cN1-2, advanced pathological stage, adjuvant treatment, and EGFR or ALK were strongly associated with SND. No significant differences were found in overall survival, disease-free survival, and overtime survival after propensity adjustment (p = 0.09, p = 0.11, and p = 0.50, respectively). There were no significant differences in local (p = 0.16), regional (p = 0.72), or distant (p = 0.39) tumor recurrence between the two groups. Conclusions: SND did not improve the prognosis of NSCLC patients with CEA abnormality. Complete pulmonary resection via L-SND seems useful for NSCLC patients with CEA abnormality.

Selective Mediastinal Lymphadenectomy or Complete Mediastinal Lymphadenectomy for Clinical Stage I Non-Small Cell Lung Cancer: A Meta-Analysis

INTRODUCTION

Selective mediastinal lymphadenectomy (SML) and complete mediastinal lymphadenectomy (CML) are two main types of surgery conducted for the treatment of non-small cell lung cancer (NSCLC) plus lobectomy or segmentectomy. It is not known whether stage I NSCLC can benefit from CML. Using the meta-analytical method, our research aimed to find out the worth of SML and CML for the therapy of clinical stage I NSCLC.

METHODS

We searched PubMed, Ovid, MEDLINE, Cochrane Controlled Trial Register (CENTRAL), Embase, and Google Scholar for literature published up to June 2021 to evaluate the comparative research and to assess the post-operative complications, overall survival rate, disease-free survival rate, and local and distant recurrence. This meta-analysis was conducted by combining the results of the reported incidences of post-operative complications, local and distant recurrence, and short- and long-term mortality. The pooled odds ratios (OR) and the 95% confidence intervals were calculated by random or fixed effects models to compare the effectiveness between these two methods.

RESULTS

Five retrospective studies and one randomized controlled trial study were included in our research. The six studies included a total of 5713 patients, of whom 1480 were assigned to the SML group and 4233 were assigned to the CML group. No statistically significant differences were found in the 1- and 5-year overall survival rates or the 1-, 3-, and 5-year disease-free survival rates between the two groups. However, the 3-year overall survival favored the SML group (P < 0.05). There were also no statistically significant differences between the local and distant metastasis. Among the postoperative complications, pneumonia, atelectasis, and prolonged air leak were more common in the CML group (P < 0.05). There were no differences in the prevalence of dysrhythmia, chylothorax, acute respiratory distress syndrome, or recurrent laryngeal nerve injury between the two groups, which may be due to the limited sample size.

CONCLUSION

Considering the comparable survival rates, disease control, and fewer postoperative complications in the evaluated participants, SML is the preferred treatment with less invasiveness for clinical stage I NSCLC.