Abstract
Cancerous micrometastasis of the lymph nodes generally indicates the lymph nodes with potentially positive metastasis which are diagnosed as those without metastasis by the ordinary pathological investigation. However, there are several problems with regard to the definition, methods for detection, and clinical significance. The first problem is difference of methods for detection, such as serial section methods, immunohistochemical methods, and PCR (polymerase chain reaction) methods, which show the different results. False-positive and false negative reaction may be possible and reproduction of the results are difficult in any of these methods. The second problem is that the reported and investigated cases are few, because of the complicated methods. The third problem is that the definitions of micrometastasis of lymph nodes are not unified. The forth problem is that the significance of lymph node metastasis as the prognostic factor is different among various organs. We confirmed the new method of a serial section method combined with an immunohistochemical method and showed the possibilities of more accurate detection of cancerous micrometastasis of the lymph nodes. Using this method, we investigated the micrometastasis of lymph nodes in cases with hepatic hilar carcinoma. The five year survival after resection in the cases with positive micrometastasis of lymph nodes,31.2%, showed no difference from that of cases with positive lymph nodes metastasis by the ordinal histological detection methods,19.7%, but showed the tendency of worse prognosis than that of cases with negative lymph nodes metastasis by the ordinary methods,57.5%.
