Is invasive mediastinal staging necessary in intermediate risk patients with negative PET/CT?

Presurgical invasive mediastinal staging in lung cancer, unexpected N2 and long-term survival: a registry-based study with data from the Spanish group for video-assisted thoracic surgery

Background

Mediastinal lymph node staging is a key element in the diagnosis of lung cancer. The combination of computed tomography (CT) and positron emission tomography (PET) has improved staging but some circumstances are known to influence their negative predictive value. The objective of this study was to assess the impact on survival of avoiding invasive mediastinal staging in surgical lung cancer patients with negative mediastinum in CT and PET and intermediate risk of unexpected pN2.

Methods

Data were collected from the prospective cohort of the Spanish Group for Video-Assisted Thoracic Surgery (GEVATS), from December 2016 to March 2018. For this study, patients were selected if they had negative mediastinum in CT and PET findings but tumours >3 cm or located centrally, or with cN1 disease. Patients who did and did not undergo invasive staging [invasive group (IG) and non-invasive group (NIG)] were compared, analysing unexpected pN2 and survival with Kaplan-Meier curves and Cox regression.

Results

A total of 2,826 patients underwent surgery for primary lung cancer. We selected 1,247 patients who had tumours >3 cm, central tumours or cN1. Invasive staging was performed in 275 (22.1%) cases. The unexpected pN2 rate was 9.6% in the NIG and 13.8% in the IG, but half of them were discovered prior to surgery in the IG. Five-year overall survival (OS) was poorer in the IG (52.4% vs. 64%; P<0.001). In the Cox regression model, male sex, older age, diabetes, synchronous tumour, lower diffusing capacity for carbon monoxide, larger tumour size, higher pathological N-stage, and IG status were significant independent risk factors.

Conclusions

Invasive staging recommended by guidelines could be reduced with an appropriate selection in mediastinal CT- and PET-negative patients with risk factors for unexpected pN2, because rates of pN2 and survival did not worsen without invasive staging.

Clinical Effect of Endosonography on Overall Survival in Patients with Radiological N1 Non-Small Cell Lung Cancer

PURPOSE

It is unclear whether performing endosonography first in non-small cell lung cancer (NSCLC) patients with radiological N1 (rN1) has any advantages over surgery without nodal staging. We aimed to compare surgery without endosonography to performing endosonography first in rN1 on the overall survival (OS) of patients with NSCLC.

MATERIALS AND METHODS

This is a retrospective analysis of patients with rN1 NSCLC between 2013 and 2019. Patients were divided into 'no endosonography' and 'endosonography first' groups. We investigated the effect of nodal staging through endosonography on OS using propensity score matching (PSM) and multivariable Cox proportional hazard regression analysis.

RESULTS

In the no endosonography group, pathologic N2 occurred in 23.0% of patients. In the endosonography first group, endosonographic N2 and N3 occurred in 8.6% and 1.6% of patients, respectively. Additionally, 51 patients were pathologic N2 among 249 patients who underwent surgery and mediastinal lymph node dissection (MLND) in endosonography first group. After PSM, the 5-year OSs were 68.1% and 70.6% in the no endosonography and endosonography first groups, respectively. However, the 5-year OS was 80.2% in the subgroup who underwent surgery and MLND of the endosonography first group. Moreover, in patients receiving surgical resection with MLND, the endosonography first group tended to have a better OS than the no endosonography group in adjusted analysis using various models.

CONCLUSION

In rN1 NSCLC, preoperative endosonography shows better OS than surgery without endosonography. For patients with rN1 NSCLC who are candidates for surgery, preoperative endosonography may help improve survival through patient selection.

Rate and Predictors of Unforeseen PN1/PN2-Disease in Surgically Treated cN0 NSCLC-Patients with Primary Tumor > 3 cm: Nationwide Results from Italian VATS-Group Database

Background. Since no robust data are available on the real rate of unforeseen N1-N2 disease (uN) and the relative predictive factors in clinical-N0 NSCLC with peripheral tumours > 3 cm, the usefulness of performing a (mini)invasive mediastinal staging in this setting is debated. Herein, we investigated these issues in a nationwide database. Methods. From 01/2014 to 06/2020, 15,784 thoracoscopic major lung resections were prospectively recorded in the “Italian VATS-Group” database. Among them, 1982 clinical-N0 peripheral solid-type NSCLC > 3 cm were identified, and information was retrospectively reviewed. A mean comparison of more than two groups was made by ANOVA (Bonferroni correction for multiple comparisons), while associations between the categorical variables were estimated with a Chi-square test. The multivariate logistic regression model and Kaplan–Meyer method were used to identify the independent predictors of nodal upstaging and survival results, respectively. Results. At pathological staging, 229 patients had N1-involvement (11.6%), and 169 had uN2 disease (8.5%). Independent predictors of uN1 were SUVmax (OR: 1.98; CI 95: 1.44–2.73, p = 0.0001) and tumour-size (OR: 1.52; CI: 1.11–2.10, p = 0.01), while independent predictors of uN2 were age (OR: 0.98; CI 95: 0.96–0.99, p = 0.039), histology (OR: 0.48; CI 95: 0.30–0.78, p = 0.003), SUVmax (OR: 2.07; CI 95: 1.15–3.72, p = 0.015), and the number of resected lymph nodes (OR: 1.03; CI 95: 1.01–1.05, p = 0.002). Conclusions. The unforeseen N1-N2 disease in cN0/NSCLCs > 3 cm undergoing VATS resection is observable in between 12 and 8% of all cases. We have identified predictors that could guide physicians in selecting the best candidate for (mini)invasive mediastinal staging.