Incorporation of the lepidic component as an additional pathological T descriptor for non-small cell lung cancer: Data from 3335 cases of lung adenocarcinoma

OBJECTIVES

The Lepidic Component (LP) identifies a subgroup with an excellent prognosis for lung adenocarcinoma (LUAD). Our research aimed to propose an improved pathological T (pT) stage for LUAD based on LP.

MATERIALS AND METHODS

Totally, 3335 surgical patients with pathological stage I LUAD were incorporated. Factors affecting survival were investigated by analyzing recurrence-free survival (RFS) and overall survival (OS) using the Kaplan-Meier method and Cox regression analyses. Subgroup analysis based on Lepidic Ratio (LR) was further evaluated. The net benefit from the modified pT category (pTm) was assessed using the Area Under the time-dependent Receiver Operating Curve (AUC), Harrell's Concordance Index (C-index), Reclassification Improvement (NRI), and Integrated Discrimination Improvement (IDI).

RESULTS

The presence of LP (LP+) was identified in 1425 (42.7 %) patients, indicating a significantly better RFS (P < 0.001) and OS (P < 0.001) than those without LP, and similar results were reproduced in pT1a-pT2a subcategory (P < 0.050 for all). Multivariable Cox analysis revealed LP+ as an independent prognostic factor for both RFS (HR, 0.622; P < 0.001) and OS (HR, 0.710; P = 0.019). However, lepidic ratio (LR) was not independently associated with both RFS and OS for LP+ patients. The 5-year RFS and OS rates between T1a (LP-) and T1b (LP+), T1b (LP-) and T1c (LP+), and T1b (LP-) and T2a (LP+) were comparable (P > 0.050 for all). After modification, compared with current 8th edition pT stage system (pT8), pTm independently predicted RFS and OS, and AUCs, c-index, NRI, and IDI analysis all demonstrated pTm holds better discrimination performances than pT8 for LUAD prognosis.

CONCLUSION

LP can be an additional down-staged T descriptor for pathological stage I LUAD and improve the survival predictive performance of reclassification.

Proposal for Rib invasion as an independent T descriptor for non-small cell lung cancer: A propensity-score matching analysis

INTRODUCTION

To evaluate the prognosis between patients with non-small cell lung cancer (NSCLC) invading difference depth of chest wall and estimate the impact of rib invasion on the pathological T classifications (pT).

METHODS

We retrospectively evaluated 521 patients with resected pT3-4 NSCLC. Propensity-score matching (PSM) balanced the known confounders of the prognosis, resulting in two sets (rib invasion vs the pT3 and pT4 group). Recurrence-free survival (RFS) and Overall survival (OS) was assessed by Cox regression and Kaplan-Meier methods. Time-dependent receiver operating characteristic (ROC) curves were used to assess the additional benefit for survival prediction after reclassifying rib invasion cases.

RESULTS

Chest wall invasion occurred in 171 patients (62 rib invasion, 51 parietal pleural invasion [PL3] and 58 soft tissue invasion). Rib invasion was found to be an independent prognostic factor for both RFS (p = 0.006) and OS (p < 0.001) of pT3-4 NSCLC. The survival of rib invasion group was the worst (RFS: 13.1%; OS: 19.8%), followed by PL3 (RFS: 34.2%, P = 0.001; OS: 48.8%; p < 0.001) and the soft tissue invasion group (RFS: 40.6%, p = 0.001; OS: 57.7%, p < 0.001). Besides, the prognosis of rib invasion group was also found to be worse than those of pT3 (RFS: p < 0.001; OS: p < 0.001) and pT4 group (RFS: p = 0.002; OS: p < 0.001). After PSM, the 5-year RFS rate of rib invasion group were still lower than that of pT3 and pT4 group (p < 0.001); the 5-year OS rate of rib invasion was similar with that of pT4 group (p = 0.066) but lower than that of pT3 group (p = 0.014). The time-dependent ROC curves demonstrated that reclassifying rib invasion as pT4 disease provided an additional benefit for survival prediction (p < 0.001).

CONCLUSION

The rib invasion group had a worse prognosis than the PL3 and pT3 groups. The prognostic impact of rib invasion should be further validated as a pT4 disease in the TNM classification.