Genetic mutations such as EGFR, ALK are key mutation in the patients of NSCLC. The ratio of lymph node metastasis of ALK positive patients is said to be higher than other mutations.Genetic mutations such as EGFR, ALK are key mutation in the patients of NSCLC. The ratio of lymph node metastasis of ALK positive patients is said to be higher than other mutations.
All of 648 patients in Aichi Cancer Center Hospital underwent lung resection with lymph node dissection between January 2012 to July 2015 for primary lung adenocarcinoma, among which 19 patients with ALK mutation and 237 patients with EGFR (L858R or Exon19 del.) mutation enrolled in this study. The clinicopathological characteristics (gender, age, smoking history, tumor size, SUV max of tumor, FDG accumulation of lymph nodes, preoperative CEA, pathological lymph node metastasis) were compared between the two groups.
In pN1-2, all (8/8, 100%) patients harboring ALK were diagnosed as cN0 by preoperative PET evaluation, whereas 32.1% (18/56) patients harboring EGFR were diagnosed as cN0. In the patients with pN1-2 showing no FDG accumulation on PET for lymph node, the maximum tumor size (MTS) and mediastinal size on CT tended to be smaller in ALK (mean 29.1 and 29.0 mm) than EGFR (34.0 and 31.2 mm), and the proportion of solid component (consolidation/MTS) was also larger in ALK (8/8, 100%) than EGFR (30/38, 78.9%), but the significant differences were not obtained respectively (p = 0.27, p = 0.50 and p = 0.37). No significant differences were observed for smoking index (p = 0.40) and preoperative CEA (p = 0.66), but patients harboring ALK were younger than those of EGFR (p < 0.01).
Detection of preoperative lymph node metastasis for ALK harboring patients tended to be difficult. Further studies in genetic mutations for NSCLC are needed.
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All authors have declared no conflicts of interest.