Frequency and clinical impact of lymph node micrometastasis and tumor cell microinvolvement in patients with adenocarcinoma of the esophagogastric junction

BACKGROUND: Tumor involvement of regional lymph nodes has a crucial impact on the prognosis of patients with adenocarcinoma of the esophagogastric junction (AEG). Although additional tumor cell deposits can be detected by sensitive methods (e.g., immunohistochemistry and polymerase chain reaction), their prognostic significance is uncertain. METHODS: Using immunohistochemistry for cytokeratins (AE1/AE3 antibody), the authors studied 3987 regional lymph nodes from 145 patients with completely resected adenocarcinoma of the esophagus (AEG I; n = 46 patients), cardia (AEG II; n = 79 patients), and subcardial region (AEG III; n = 20 patients). The newly detected cells were categorized with tumor cell microinvolvement (TCM) or with micrometastases (MM) based on tumor size and histology. RESULTS: Of the 75 pathologic lymph node negative (pN0) patients, 3 of 30 patients in the AEG I group (10%) and 8 of 45 patients in the AEG II and III groups (18%) had TCM (no significant difference). MM was found in 2 of 30 tumors in the AEG I group (7%) and in 11 of 45 tumors in the AEG II and III groups (24%), a significantly lower rate that that in the AEG I group (P < 0.05). Neither TCM nor MM showed a significant prognostic impact in AEG I tumors (P > 0.05). For the AEG II and III tumors, MM (new lymph node positive [pN+] cases) had a prognostic impact similar to metastases found by routine methods, with reclassification based on MM resulting in improvement in the pN0 group from 72.8 months to 82.6 months, but almost no change was seen in the pN+ group (49.9-49.2 months). TCM had no adverse impact on survival in any tumor type. CONCLUSIONS: These results highlight important differences between AEG I tumors and AEG II and III tumors and argue for different lymphadenectomy strategies for patients with these tumor types.