Lymph Node Micrometastasis Prognosticates Survival for Patients with Stage 1 Bronchogenic Adenocarcinoma
This study aimed to investigate the significance of lymph node micrometastasis (LNMM) in the lung cancer nodal categories.
Between 1 January 2009 and 31 December 2013, 589 patients with suspected c-stage 1 and p-T1-2aN0-1M0 lung adenocarcinoma were enrolled in this study. The study evaluated LNMM with cytokeratin (AE1/AE3) and transcription factor-1 (TTF1) (8G7G3/1) expression by immunohistochemistry. Recurrence-free survival (RFS) and overall survival (OS) were compared among the T1-2aN0-1M0 patients stratified by the new N categories.
From 589 patients, 7892 removed lymph nodes were examined, and LNMM was observed in 55 (9.3%) of the patients. The patients without LNMM or N1 had the best RFS (5-year rate: 80% vs 25%; P < 0.001) and OS (5-year rate: 87% vs 43%; P < 0.001), followed by the patients with LNMM, compared with those in the N1 category (RFS: 5-year rate, 25% vs 8%; P = 0.010; OS: 5-year rate, 43% vs 20%; P = 0.009). Similarly, this trend was observed when patients were subdivided into the T1 and T2a categories. Multivariate analysis showed that the new N categories with the addition of LNMM were an independent prognostic factor. This result also was noticed in all subgroups.
The findings showed LNMM to be clinically significant as a risk factor for lung cancer. Clinicians should consider LNMM when estimating N categories to determine prognosis and the best treatment strategy.
This study was supported by the projects from the Shanghai Hospital Development Center (SHDC12015116), the Natural Science Foundation of Shanghai Minhang District (2016MHZ52), the Health and Family Planning Commission of Shanghai Municipality (2013ZYJB0003 and 20154Y0097), and the Shanghai Pujiang Program (15PJD034).
There are no conflicts of interest.
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