Can a Thoracic Surgeon Identify Lymph Node Metastases during Surgery Based on Their Size?: Analysis of 844 Metastatic and 10,462 Nonmetastatic Lymph Nodes

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.

Enlarged Mediastinal Lymph Nodes in Computed Tomography are a Valuable Prognostic Factor in Non-Small Cell Lung Cancer Patients with Pathologically Negative Lymph Nodes

Background

Most non-small cell lung cancer patients with enlarged mediastinal lymph nodes (LN) in preoperative computer tomography (CT) images are diagnosed with N0 in the pathological examination after surgery. However, these patients seem to have worse survival than those without enlarged mediastinal LN in our clinical practice. This study aimed to investigate whether the size of mediastinal LN is correlated with the prognosis in pathological N0 patients, which could help us to predict the prognoses further.

Methods

The retrospective cohort study involved 758 N0 patients with a thin layer CT scan. We have measured the size of mediastinal LN, including long diameter, short diameter, and volume on CT image, and classified patients by X-tile. Next, we explored the risk factors of enlarged LN by univariate and multivariate logistic analysis. Then, we have compared the 5-year cancer-specific survival by Kaplan-Meier and log-rank method. Multivariate Cox analysis was utilized to further survival analysis. Finally, we have constructed the prediction model by nomogram.

Results

A total of 150 N0 patients (19.8%) had mediastinal LN enlargement in our study. After multivariate logistic analysis, we found the LN enlargement was significantly correlated with age (p=0.001), pathology (p < 0.001) and tumor recurrence (p < 0.001). The patients with LN enlargement had a worse 5-year cancer-specific survival (75.3% vs 92.8%, p < 0.001) after Kaplan-Meier analysis. Patients with a larger volume had increased risk of tumor-associated death when compared with the normal group (p < 0.001) by multivariate Cox analyses.

Conclusion

N0 patients with larger mediastinal LN had a worse 5-year cancer-specific survival and a higher risk of recurrence. The volume of LN was the most valuable prognostic factor in N0 patients.

Independent risk factors for lymph node metastasis in 2623 patients with Non-Small cell lung cancer

PURPOSE

this study attempts to identify the independent risk factors that can predict lymph node metastasis for the patients with non-small cell lung cancer (NSCLC), and guide doctor adoption of individualized treatment for such patients.

MATERIALS AND METHODS

This study was approved by the Hospital's Ethics Committee and all patients had signed informed consent forms. We retrospectively reviewed NSCLC patients who had undergone surgical resection from December 2008 to December 2013.The statistical significance of evaluation variables and lymph node metastasis was determined with Pearson's Chi-square test. The risk factors of lymph node metastasis were determined through univariate and multivariate logistic regression analysis. And for the age and tumor diameter factors, optimal cutoff points were determined with a receiver operating characteristic analysis.

RESULTS

In the present study, a total of 2623 patients were included in the study, and 779 patients with lymph node metastasis. Three independent risk factors were identified: age, tumor diameter and Ki-67 index. We found that <65 years of age (Adjusted-OR:1.921), ≥2.85 cm of tumor diameter (Adjusted-OR:3.141), and 5%~25% in Ki-67 group (Adjusted-OR:2.137),≥25% (Adjusted-OR:3.341) were significant. Also we found that 307 patients with lymph node metastasis and the lymph node metastasis rate was 51.0%, when the age<65 years, Ki-67 index≥25%, and the tumor diameter≥2.85 cm. On the contrary, there were only 2 patients with lymph node metastasis, and the rate of lymph node metastasis was 5.1%.

CONCLUSION

Identifying three independent risk factors that predict lymph node metastasis in non-small cell patients, Among NSCLC patients in whom all three predictors were identified, and over a half of the patients showed lymph node metastasis.

Nodal size ranking as a predictor of mediastinal involvement in clinical early-stage non-small cell lung cancer

In non-small cell lung cancer (NSCLC) patients, the recommended minimum requirement for an endoscopy-based mediastinal staging procedure is sampling the largest lymph node (LN) in right and left inferior paratracheal, and subcarinal stations. We aimed to analyze the percentage of cases where the largest LN in each mediastinal station was malignant in a cohort of NSCLC patients with mediastinal metastases diagnosed in the lymphadenectomy specimen. Furthermore, we investigated the sensitivity of a preoperative staging procedure in a hypothetical scenario where only the largest LN of each station would have been sampled.Prospective data of patients with mediastinal nodal metastases diagnosed in the lymphadenectomy specimens were retrospectively analyzed. The long-axis diameter of the maximal cut surface of all LNs was measured on hematoxylin and eosin-stained sections.Seven hundred seventy five patients underwent operation and 49 (6%) with mediastinal nodal disease were included. A total of 713 LNs were resected and 119 were involved. Sixty seven nodal stations revealed malignant LNs: in these, the largest LN was malignant in 39 (58%). In a "per patient" analysis, a preoperative staging procedure that sampled only the largest LN would have attained a sensitivity of 0.67; and if the largest and the second largest were sampled, sensitivity would be 0.87.In patients with NSCLC, nodal size ranking is not reliable enough to predict malignancy. In clinical practice, regardless of the preoperative staging method, systematic thorough sampling of all visible LNs is to be recommended over selective random samplings.

[Utility of PET/CT for mediastinal staging of non-small cell lung cancer in stage III (N2)]

PURPOSE

To evaluate the accuracy of integrated positron emission tomography with (18)F-fluoro-2-deoxy-D-glucose (FDG) and computed tomography (PET/CT) in mediastinal lymph node staging in patients with potentially operable (N2) non-small cell lung cancer (NSCLC) and to ascertain the role of invasive staging in verifying positron emission tomography (PET)/computed tomography (CT) results.

MATERIAL AND METHODS

A retrospective study of consecutive patients with pathologically-proven NSCLC and N2 staging by enhanced CT was performed. A PET/CT scan was performed for all the patients. Lymph node staging was pathologically confirmed when it was possible or by consensus in the Thoracic Cancer Committee. Sensitivity, specificity, negative predictive value and positive predictive value of PET/CT in N2 cases were determined.

RESULTS

A total of 34 patients with N2 by CT were evaluated. PET/CT showed N2 in 30 patients. Discrepancies were found in four patients, two patients were classified as N1 in PET/CT and two patients as N0. Lymph node staging was pathologically confirmed in 20 patients. No false positives were found in PET/CT study. Sensitivity was 94.7%, specificity and positive predictive values were 100% and negative predictive value was 50%.

CONCLUSIONS

Our data show that integrated PET/CT provides high sensitivity and positive predictive value in mediastinal nodal staging of NSCLC patients. Therefore, in patients with potentially resectable lung cancer, neoadjuvant chemotherapy candidate, mediastinoscopy could be reserved for restaging after induction therapy.