Lymph Node and Bone Marrow Micro-Metastasis in Patients with Esophageal Cancer

Esophageal cancer (EC) is the sixth most common cause of cancer-related mortality globally, due to the high frequency of early metastatic disease. In the past, the presence of metastasis was examined based on histological analysis using hematoxylin and eosin (HE) staining. A high percentage of patients experience recurrence after metastasectomy. Recurrence could be due to the presence of micro-metastasis (MM), which could be detected at sites such as lymph nodes or bone marrow using RT-PCR or immune-histochemical staining. Previous studies have reported inconsistent results with respect to the clinical significance of MM, its impact on survival, and how it is affected by chemotherapy. In this study, we reviewed the (1) clinical significance of MM, (2) methods of detection, (3) sites of occurrence, (4) the mechanism associated with MM, and (5) the role of chemotherapy and radiotherapy in patients with EC.