Background. The long-term prognosis after surgical therapy for esophageal carcinoma depends on tumor stage and completeness of resection. Similarly to other epithelial tumors, the presence of micro deposits of neoplastic cells in the bone marrow may indicate residual disease and the potential for recurrence. This study assesses the prevalence of bone marrow-disseminated tumor cells in patients undergoing surgical resection for esophageal carcinoma. In addition, we investigated the agreement between immunohistochemical and molecular techniques for the detection of micrometastases in a subgroup of patients. Methods. Between January 1998 and November 1999, forty-eight patients with adenocarcinoma of the esophagogastric junction (n = 29) or squamous cell carcinoma of the thoracic esophagus (n = 19) and no evidence of overt metastatic disease entered the study. An immunohistochemical assay (capable of detecting 1 carcinoma cell in 7 × 105 bone marrow cells) was used to test bone marrow obtained by flushing a resected rib or by needle aspiration either of the iliac crest or of a rib. A polymerase chain reaction (PCR) molecular technique was also used to identify bone marrow and peripheral blood epithelial cells. Results. Cytokeratin-positive cells were found in 79.1% of the bone marrow samples obtained from the rib, and in only 8% of the needle aspirates either from the iliac crest or from a contiguous rib: This difference is probably explained by the improved removal of metastatic cells with the flushing of the rib. Comparable results were obtained at a qualitative level by the PCR technique on bone marrow. In addition, PCR-positive results were found in 3 of 18 peripheral blood samples. There was no association with tumor type, neoadjuvant therapy, or lymph node status. Patients with a pT3 or pT4 tumor showed, at a borderline statistical level, a higher proportion of cytokeratin-positive cells in the flushed rib. Conclusions. Bone marrow-disseminated tumor cells are present in the resected rib of a high proportion of patients undergoing esophagectomy for carcinoma, and immunohistochemistry seems to be the method of choice for their quantitative assessment. However, the prognostic and therapeutic implications of this finding need further investigation.
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