Micrometastases in esophagogastric cancer: High detection rate in resectedrib segments

Background & Aims: Micrometastases within bone marrow indicate a poor progn osis. We prospectively examined micrometastases in patients undergoing rese ction of esophagogastric cancers for (1) prevalence in rib marrow; (2) comp arative detection rates in rib and iliac crest marrow; (3) responsiveness t o neoadjuvant therapy; and (4) viability and tumorigenicity. Methods: In 50 consecutive patients, marrow was obtained before manipulation of the prima ry tumor. Micrometastatic cells were detected by staining contaminant cytok eratin-18-positive cells. Viability and tumorigenicity were determined by c ulture 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% (2 4 of 27) for ribs (P < 0.001). Detection rates were independent of histolog ical type or nodal status and were similar in patients with and without neo adjuvant therapy. Metastatic cells were cultured from rib marrow of 5 of 7 patients and were tumorigenic in nude mice. Conclusions: Most patients unde rgoing resection of esophagogastric malignancies have micrometastases in ri b marrow, Detection rates based on iliac crest marrow are underestimates. H ematogenous spread of metastatic cells is independent of histological type or nodal status. The metastatic cells are viable, tumorigenic, and resistan t to neoadjuvant therapy.