Prognostic value of uncertain resection for overall survival in non-small cell lung cancer

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.

Spread Through Air Spaces in Residual Tumor Classification for Clinical IA Lung Adenocarcinoma

BACKGROUND

We aimed to validate the prognostic implication of uncertain resection, R(un), proposed by International Association for the Study of Lung Cancer (IASLC) and evaluate the prognostic value of spread through air spaces (STAS) in reclassifying the R classification among patients with lung adenocarcinoma after segmentectomy.

METHODS

We enrolled 1007 patients who underwent segmentectomy for c-stage IA lung adenocarcinoma between 2014 and 2017. Recurrence-free survival (RFS) and overall survival (OS) were compared to evaluate the prognostic value of IASLC-R(un) and STAS. Whether STAS would skip into complementary lobectomy was evaluated in a prospective cohort.

RESULTS

The current IASLC-R(un) failed to significantly stratify the RFS (P = .078) in segmentectomy, and STAS was a stronger risk factor of poor prognosis for both RFS and OS (P < .001). Moreover, the presence of STAS was associated with increased locoregional recurrence in patients undergoing segmentectomy (P < .001) but not in those treated with lobectomy (P = .187), indicating that only STAS-positive segmentectomy was consistent with the concept of R(un) in relapse pattern. After reclassifying STAS-positive segmentectomy into the R(un) category, the proposed R(un) showed an improvement in prognosis stratification. In addition, 2 of 30 patients (6.2%) in the prospective cohort who underwent initial segmentectomy and complementary lobectomy had STAS clusters in the complementary lobectomy specimens.

CONCLUSIONS

Unfavorable prognosis, relapse patterns consistent with R(un), and pathologic verification that saltatory spread of STAS observed in complementary lobectomy specimens supported reclassifying STAS-positive segmentectomy as R(un). STAS is a critical concern for the surgical completeness evaluation after segmentectomy.

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.