[Clinical significance of molecular biological detection of micrometastases in gastric carcinoma].

Micrometastases are considered to be a cause of recurrence after curative surgery for gastric cancer. It is important to clarify the clinicopathologic characteristics of micrometastases in the lymph nodes and peritoneal cavity to determine the treatment options in gastric cancer. Two consecutive sections of lymph nodes from patients with various cancers were examined by simultaneous staining with ordinary hematoxylin and eosin (H & E) and immunostaining with anti-cytokeratin antibody, respectively. Micrometastases in the lymph nodes were found in 18% of mucosal cancer, 25% of submucosal cancer, and 65% of T3 (serosal) cancers pecimens, with cancer-free nodes examined by H & E staining. A reduced 5-year survival rate was demonstrated in patients with nodal micrometastases among those with submucosal cancer and those with T3 cancer and cancer-free nodes examined by H & E staining. Molecular biological detection (MBD) of micrometastasis in lavage cytology specimens was performed by RT-PCR of carcinoembryonic antigen mRNA or telomerase activity assay. MBD protocols revealed micrometastases in cases with negative cytology results. Survival analysis demonstrated peritoneal recurrences in MBD-positive cases, whereas there was no recurrence in MBD-negative cases. Peritoneal micrometastases detected by MBD protocols appear to be a significant risk factor for recurrence. Therefore indications for lymph node dissection and postoperative chemotherapy should be determined based on the findings of micrometastases in gastric cancer.