Validation of the IASLC Residual Tumor Classification in Patients With Stage III-N2 Non-Small Cell Lung Cancer Undergoing Neoadjuvant Chemoradiotherapy Followed By Surgery

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for Revision of the Classification of Residual Tumor After Resection for the Forthcoming (Ninth) Edition of the TNM Classification of Lung Cancer

INTRODUCTION

The goal of surgical resection is to completely remove a cancer; it is useful to have a system to describe how well this was accomplished. This is captured by the residual tumor (R) classification, which is separate from the TNM classification that describes the anatomic extent of a cancer independent of treatment. The traditional R-classification designates as R0 a complete resection, as R1 a macroscopically complete resection but with microscopic tumor at the surgical margin, and as R2 a resection that leaves gross tumor behind. For lung cancer, an additional category encompasses situations in which the presence of residual tumor is uncertain.

METHODS

This paper represents a comprehensive review of evidence regarding these R categories and the descriptors thereof, focusing on studies published after the year 2000 and with adjustment for potential confounders.

RESULTS

Consistent discrimination between complete, uncertain, and incomplete resection is revealed with respect to overall survival. Evidence regarding specific descriptors is generally somewhat limited and only partially consistent; nevertheless, the data suggest retaining all descriptors but with clarifications to address ambiguities.

CONCLUSION

On the basis of this review, the R-classification for the ninth edition of stage classification of lung cancer is proposed to retain the same overall framework and descriptors, with more precise definitions of descriptors. These refinements should facilitate application and further research.

Validation of the Proposed International Association for the Study of Lung Cancer Residual Tumor Classification to Upgrade Extracapsular Extension of Tumor in Nodes From R0 to Incomplete Resection

INTRODUCTION

The International Association for the Study of Lung Cancer (IASLC) proposed a revised R classification to upstage extracapsular extension (ECE) of tumor in nodes from R0 to R1. Nevertheless, evidence to confirm this proposal is insufficient.

METHODS

The study included 4061 surgical patients with NSCLC. After reclassification by IASLC-R classification, overall survival (OS) was analyzed to compare patients with ECE with those with R0, R(un), and incomplete resection (R1 and R2). The recurrence pattern of ECE was evaluated to determine whether it correlated with incomplete resection.

RESULTS

Among 1136 patients with N disease, those without ECE (n = 754, 67%) had a significantly better OS than those with ECE (n = 382, 33%) (p < 0.001). This negative prognostic significance was consistent across multiple subgroups. Multivariate analysis revealed that ECE was an independent prognostic risk factor (p < 0.001). When patients with ECE were separated from the IASLC-R1 group, their OS was significantly worse than that of IASLC-R(un) patients, but comparable to that of the remaining patients in the IASLC-R1 patients when analyzing all patients and patients with N disease. Moreover, patients with ECE had an increased risk of local recurrence in the mediastinum (p < 0.001), ipsilateral lung (p = 0.031), and malignant pleural effusion or nodes (p = 0.004) but not distant recurrence including contralateral or both lungs (p = 0.268), liver (p = 0.728), brain (p = 0.252), or bone (p = 0.322).

CONCLUSIONS

The prognosis of ECE patients is comparable with that of R1 patients. Moreover, their higher risk of local recurrence strongly suggests the presence of occult residual tumor cells in the surgical hemithoracic cavity. Therefore, upgrading ECE into incomplete resection is reasonable.

Investigation of the non-small cell lung cancer patients with uncertain resection: A population-based study

OBJECTIVES

We aimed to investigate the clinical features, prognosis and predictive factors for the non-small cell lung cancer (NSCLC) patients with uncertain resection [R(un)].

MATERIALS AND METHODS

Kaplan-Meier method with a log-rank test was used to compare overall survival (OS) and disease-free survival (DFS) between groups. The least absolute shrinkage and selection operator (LASSO)-penalized Cox multivariable analysis was used to identify the prognostic factors. Random forest was used to determine the important predictive factors of R(un) resection.

RESULTS

A total of 2,782 eligible cases (R0 group: 1,897 cases; R(un) group: 885 cases) were included in this study. The rate of conventional R0 to R(un) reclassification was 31.8%. Patients with R(un) resection were more likely to have left-sided tumors, receive open surgery, and be diagnosed with advanced tumors. The survivals of the patients with R(un) resection were inferior to those of the patients with R0 resection in the entire cohort and in the nodal category, histology and adjuvant therapy subgroups. The LASSO-penalized multivariable Cox analysis confirmed that R(un) resection was an adverse prognostic factor for both OS and DFS. At last, surgical extent, surgical approach and tumor location were proven as the predictive factors for R(un) resection.

CONCLUSION

NSCLC patients with R(un) resection was not rare. R(un) had an adverse impact on the survivals of resected patients. Patients received non-lobectomy and open surgery, and patients with left-sided tumors were more likely to be suffered from R(un) resection.