Micrometastases in Esophagogastric Cancer

Background& Aims: Micrometastases within bone mar- row indicate a poor prognosis. We prospectively exam- ined micrometastases in patients undergoing resec- tion of esophagogastric cancers for (1) prevalence in rib marrow; (2) comparative detection rates in rib and iliac crest marrow; (3) responsiveness to neoadjuvant therapy; and (4) viability and tumorigenicity. Methods: In 50 consecutive patients, marrow was obtained before manipulation of the primary tumor. Micrometa- static cells were detected by staining contaminant cytokeratin-18–positive cells. Viability and tumorigenic- ity were determined by culture and xenograft. Results: Micrometastases were detected in rib marrow from 88% of patients (44 of 50). When bilateral iliac crest marrow was also obtained, micrometastases were found in 15% (4 of 27) compared with 89% (24 of 27) for ribs (PF0.001). Detection rates were independent of histological type or nodal status and were similar in patients with and without neoadjuvant therapy. Meta- static cells were cultured from rib marrow of 5 of 7 patients and were tumorigenic in nude mice. Conclusions: Most patients undergoing resection of esophagogastric malignancies have micrometastases in rib marrow. Detection rates based on iliac crest marrow are underestimates. Hematogenous spread of metastatic cells is independent of histological type or nodal status. The metastatic cells are viable, tumori- genic, and resistant to neoadjuvant therapy.