Objective: To detect micrometastasis in regional lymph nodes using RT- PCR assay and evaluate the significance of the new assessment of nodal status in determining pN staging in gastric carcinoma.
Methods: In addition to HE,RT- PCR assay for cytokeratin-20 gene marker was used to detect micrometastasis in 850 lymph nodes from 30 patients with gastric carcinoma who underwent gastrectomy with lymphadenectomy from Dec. 2003 to Apr. 2004.
Results: The detection rate of HE staining was 27.1% (233/850), the detection rate of RT-PCR assay was 36.5% (310/850) (Pa< 0.01). Lymph node micrometastasis was further detected in 77 nodes from 14 patients. The detection rate of RT- PCR assay from the routine negative lymph nodes was 12.5% (77/617). Seven of those patients were up- staged (from IB stage to II stage, from IB stage to III A stage, from I stage to III A stage, from III A stage to III B stage, from III A stage to IV stage in one patient respectively, and from III B stage to IV stage in 2 patients).
Conclusion: RT- PCR assay can increase the detection rate of lymph node metastasis and have a significant impact on the staging system of gastric carcinoma.