Abstract
INTRODUCTION: This study determined the prevalence of anaplastic lymphoma kinase (ALK) rearrangement, and identified the associations of ALK rearrangement with clinicopathologic characteristics and treatment outcomes in patients with surgically-resected stage I-III lung adenocarcinoma. METHODS: A total of 534 surgically-resected lung adenocarcinoma patients were studied. The prevalence of ALK protein over-expression was determined by a fully-automated immunochemistry assay (with mouse monoclonal Ventana D5F3 antibody), and the associations of ALK rearrangement with clinicopathologic characteristics and treatment outcomes were analyzed. RESULTS: Forty-two (7.9%) of the 534 lung adenocarcinoma patients were ALK IHC-positive. ALK rearrangement was significantly associated with younger age (P = 0.011), high T-stage (P = 0.025), high pathologic stage (P = 0.002), solid predominant adenocarcinoma with mucin production (P = 0.006), invasive mucinous adenocarcinoma (P = 0.009), and receipt of adjuvant therapy after surgery (P = 0.036), but no significant associations were found between the ALK rearrangement and sex or smoking status. ALK IHC-positivity was significantly associated with a shorter disease-free survival, tumor-specific survival, and overall survival (P = 0.001, 0.026, and 0.007, respectively). Multivariate analysis showed that ALK IHC-positivity was an adverse prognostic factor for disease-free survival (HR, 1.80; 95% CI 1.18-2.77; P = 0.007), tumor-specific survival (HR, 2.59; 95% CI 1.35-4.97; P = 0.004), and overall survival (HR, 1.92; 95% CI 1.07-3.44; P = 0.030). CONCLUSION: The clinical characteristics of patients with ALK-positive lung adenocarcinoma were similar to those of EGFR-mutated patients. ALK rearrangement was an adverse prognostic factor in surgically-resected lung adenocarcinoma patients.