Tumor-associated macrophages in stage IIIA pN2 non-small cell lung cancer after neoadjuvant chemotherapy and surgery

Purpose: Most of the patients with stage IIIA pN2 non-small cell lung cancer (NSCLC) develop recurrence after surgery. It is not clear whether post neoadjuvant chemotherapy tumor-associated macrophages is associated with recurrence. Patients and Methods: Stage IIIA pN2 NSCLC patients underwent cisplatin/docetaxel neoadjuvant chemotherapy and surgery were retrospectively enrolled. Immunohistochemical staining of CD68 was used to identify macrophages in surgical resected stored tissues. Results: The objective response rate of cisplatin/docetaxel was 68%, overall median disease-free survival (DFS) was 13.1 months and median overall survival (OS) 36.8. months. Multiple Cox regression analysis showed low total macrophage numbers and mediastinal lymph nodes downstaging were independent factors for longer DFS, whereas high islet/stromal macrophages ratio was an independent facto for OS. In patients downstaged to pN0, low total macrophage numbers was also associated with longer DFS. Conclusions: Low total macrophage number is an independent factor for better DFS in pN2 stage IIIA NSCLC patients receiving neoadjuvant chemotherapy and surgical resection, which association was kept in those downstaged to pN0. Further studies are warrant to confirm the predictive role of TAMs and their potential causative role in tumor recurrence.