A Proposal for Combination of Total Number and Anatomical Location of Involved Lymph Nodes for Nodal Classification in Non-small Cell Lung Cancer

作者：Saji Hisashi^*; Tsuboi Masahiro; Shimada Yoshihisa; Kato Yasufumi; Yoshida Koichi; Nomura Masaharu; Matsubayashi Jun; Nagao Toshitaka; Kakihana Masatoshi; Usuda Jitsuo; Kajiwara Naohiro; Ohira Tatsuo; Ikeda Norihiko

来源：Chest, 2013, 143(6): 1618-1625.

DOI：10.1378/chest.12-0750

Background: We previously reported the prognostic impact of the number of involved lymph nodes (LNs) on survival in non-small cell lung cancer (NSCLC). However, it remains unknown whether the total number or anatomic location of involved LNs is a superior prognostic factor.
Methods: A total of 689 patients with NSCLC who underwent complete resection involving dissection of the hilar and mediastinal LNs with curative intent of 10 LNs were enrolled. The association between the total number of LNs (nN) involved and survival was assessed by comparison with the anatomic location of LN involvement (pathologic lymph node [pN]), the present nodal category.
Results: We classified the patients into five categories according to the combined pN and nN status as follows: pN0-nN0, pN1-nN1-3, pN1-nN4-, pN2-nN1-3, and pN2-nN4. Although there was no statistically significant difference between the pNl-nN4- and pN2-nN1-3 categories, pN2-nN1-3 had better prognoses than pNl-nN4. On multivariate analysis, the nN category was an independent prognostic factor for overall survival and disease-free survival (vs nN4; the hazard ratios of nNO and nN1-3 for overall survival were 0.223 and 0.369, respectively, P <.0001 for all), similar to the pN category. We propose a new classification based on a combination of the pN and nN categories: namely, NO becomes pN0-nN0, the Ni category becomes pN1-nN1-3, the N2a category becomes pN2-nN1-3 + pNl-nN4, and the N2b category becomes pN2-nN4. Each survival curve was proportional and was well distributed among the curves.
Conclusions: A combined anatomically based pN stage classification and numerically based nN stage classification is a more accurate prognostic determinant in patients with NSCLC, especially in the prognostically heterogeneous pN1 and pN2 cases. Further large-scale international cohort validation analyses are warranted.

• 出版日期2013-6