Abstract
BACKGROUND: Anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC) exhibited a higher propensity for lymph node metastasis (LNM). This study aimed to investigate risk factors of occult lymph node metastasis (OLNM) and recurrence in resectable ALK-rearranged NSCLC patients. METHODS: This retrospective analysis included patients with ALK-rearranged NSCLC receiving lung resections at Shanghai Pulmonary Hospital from June 2016 to August 2021. Logistic regression analysis was used to ascertain predictors of OLNM, and Cox regression analysis to identify risk factors of recurrence. RESULTS: A total of 603 resectable ALK-rearranged NSCLC patients were included. The mean age was 55 years old. There were 171 patients (28.4%) pathologically confirmed to have LNM, 51.5% of which were occult. Logistic regression analysis identified clinical tumor size and computed tomography (CT) density as independent factors for OLNM. Cox regression analysis showed that pleural invasion and pathological tumor size were independent prognosticators for recurrence in pathologically nodal negative patients. Among pathologically nodal positive patients, adjuvant ALK-tyrosine kinase inhibitors (TKI) showed a similar recurrence-free survival (RFS) to chemotherapy (hazard ratio, 0.454; 95% confidence interval, 0.111-1.864). CONCLUSIONS: Assessing the potential risk of OLNM is required for ALK-rearranged NSCLC patients with large tumors characterized by high CT densities. Patients with large pathological tumor size or pleural infiltration should be closely monitored despite being pathologically nodal negative. Additionally, adjuvant ALK-TKI may present a comparable RFS to chemotherapy in pathologically nodal positive patients.