Introduction: The 9th edition of the TNM classification for lung cancer implemented significant revisions, notably the subdivision of the N2 and M1c categories, to enhance anatomical precision and prognostic accuracy. Nonetheless, the actual effects of these modifications on stage distribution, histology-specific patterns, and clinical interpretation remain to be fully evaluated. Objectives: To compare lung cancer staging distributions between the 8th and 9th TNM editions, analyze patterns of stage migration, and evaluate histology-specific reclassification trends. Although TNM 9 applies the same descriptors across all histological subtypes, the magnitude of stage migration varies. In our cohort and in international datasets, adenocarcinoma demonstrated a higher likelihood of reclassification into advanced stages compared to other subtypes. Methods: A retrospective analysis was performed on a cohort of lung cancer patients staged according to the 8th and 9th editions of the TNM classification. Stage distribution alterations were analyzed by chi-squared tests, whereas McNemar’s test examined the directional shifts in upstaging and downstaging. Further investigations evaluated the correlation between histological subtype and stage reclassification. Results: A statistically significant redistribution of stages was noted (χ2= 1013.03, df = 64,p< 0.0001), with a notable prevalence of upstaging (p= 0.0019). The most significant proportional increase was observed in stage IIIA, mostly attributable to the N2 subdivision (N2a vs. N2b). Adenocarcinoma was the predominant histological subtype at all stages and showed a greater tendency for reclassification into advanced stages, specifically IIIA and IIIB. Squamous cell carcinoma was predominantly observed in stages IIB and IIIA, whereas small cell and large cell carcinomas were concentrated in advanced stages. These histology-specific patterns correspond with international findings, including research confirming the prognostic relevance of N2 subdivision. Conclusions: The 9th edition of the TNM classification results in significant stage migration, particularly in adenocarcinoma cases, indicating the improved sensitivity of the updated criteria in identifying advanced nodal disease. These modifications significantly impact prognostic evaluation and global comparability of clinical cohorts, supporting the implementation of TNM 9 as a more anatomically and biologically relevant staging system.
引言：第九版肺癌TNM分期系统进行了重大修订，尤其对N2和M1c亚类进行了细化，以提升解剖学精确度与预后评估准确性。然而，这些修订对分期分布、组织学特异性模式及临床解读的实际影响仍有待全面评估。目的：比较第八版与第九版TNM分期在肺癌分期分布上的差异，分析分期迁移模式，并评估组织学特异性再分类趋势。尽管TNM 9对所有组织学亚型采用相同的分类标准，但分期迁移程度存在差异。在本研究队列及国际数据集中，腺癌相较于其他亚型更易被重新分类至晚期阶段。方法：对按第八版和第九版TNM分期系统分期的肺癌患者队列进行回顾性分析。采用卡方检验分析分期分布变化，McNemar检验评估分期升级与降级的方向性变化，并进一步探究组织学亚型与分期再分类的相关性。结果：观察到具有统计学意义的分期重新分布（χ²=1013.03，df=64，p<0.0001），其中分期升级现象尤为显著（p=0.0019）。IIIA期比例增幅最大，主要归因于N2亚类细分（N2a与N2b）。腺癌在所有分期中均为主要组织学亚型，且更倾向于被重新分类至晚期（特别是IIIA和IIIB期）。鳞状细胞癌主要集中在IIB和IIIA期，而小细胞癌与大细胞癌则集中于晚期阶段。这些组织学特异性模式与国际研究结果一致，包括证实N2细分具有预后价值的研究。结论：第九版TNM分期系统导致显著的分期迁移，尤其在腺癌病例中，表明更新后的标准对晚期淋巴结疾病的识别具有更高敏感性。这些修订显著影响预后评估及临床队列的国际可比性，支持TNM 9作为更具解剖学和生物学相关性的分期系统推广应用。
From TNM 8 to TNM 9: Stage Migration and Histology-Specific Patterns in Lung Cancer
肿瘤(癌症)患者之家